LIBRARY OF THE University of California. GIFT OF .^.A.....O.....Q^... Class I 4 U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF CHEMISTRY— BULLETIN NO. 88. H. W. WILEY, Chief of Bureau. The Chemical Composition of Apples and Cider. I. The Composition of Apples in Relation to Cider and Vinegar Production. II. The Composition of Cider as Determined by Dominant Fermentation with Pure Yeasts. ^\^M. B. ALWOOD, Special Agent, U. S. Department of Agriculture, and Mycologist of the Virginia Agricultural Experiment Station. R. J. DAVIDSON, Special Agent, U. S. Department of Agriculture, and Chemist of the Virginia Agricultural Experiment Station. ^^. A. F. MOlSrCURE, Assistant Mycologist, Virginia Agricultural Experiment Station. WASHINGTON: government printing office. 1904. U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF CHEMISTRY— BULLETIN NO. 88. H. W. WILEY, Chief of Bureau. The Chemical Composition of apples and Cider. I. The Composition of Apples in Relation to Cider and Vinegar Production. n. The Composition of Cider as Determined by Dominant Fermentation with Pure Yeasts. BY Special Agent, U. S. Department of Agriculture, and Mycologist of the Virginia Agricultural Experiment Station. 11. J. T>AVIT>SOTsr, Special Agent, U. S. Department of Agriculture, and Chemist of the Virginia Agricultural Experiment Station. ^W, A. r. MONOURE, Assistant Mycologist, Virginia Agricultural Experiment Station. WASHINGTON: government printing office. 1904, LETTER OF TRANSMIHAL U. S. Department of Agriculture, Bureau of Chemistry, Washington.! D. 6^., August W^ 190 Jf,. Sir: The manuscript offered for publication herewith contains the results of elaborate studies made on the composition of apples, apple juices, and the fermented products thereof, conducted by this Bureau in collaboration with the agricultural experiment station at Blacksburg, Va., during the past two years. The chemical work was done partly in the Bureau of Chemistry, but chiefl}^ in the laboratories of the Vir- ginia station, while the fermentation experiments were made solely at the experiment station. In regard to ^ the authorship, William B. Alwood is solely responsible for the plan and direction of the work herein presented, and the report has been prepared by him. To R. J. Davidson should be accredited the chemical work done at the Virginia station, while W. A. P. Moncure had charge of the fermentation room and kept the records of that part of the work. The data obtained throw a great deal of light upon the processes of fermentation and the methods which should be used to secure the highest grade of products from the juices of apples and other fruits. The researches reported here form a sequel to Bulletin No. 71 of this Bureau, entitled "A Study of Cider Making in France, Germany, and England," and I recommend the publication of this manuscript as Bulletin No. 88 of the Bureau of Chemistry. Respectfully, H. W. Wiley, Chief. Hon. James Wilson, Secretary of Agriculture, 3 Digitized by the Internet Archive in 2007 with funding from Microsoft Corporation http://www.archive.org/details/chemicalcompositOOalworich CONTENTS. Page. I. The Composition of Apples ix Relation to Cider and Vinegar Pro- duction 7 Introduction , 7 Preparation of the samples 8 Juice and pomace 10 Dry matter and mineral constituents 18 II. The Composition of Cider as Determined by Dominant Fermentation WITH Pure Yeasts 20 Work of 1901-2 20 Introduction 20 Cask experiments Nos. 2 and ^ 21 Work of 1903-4 25 First series of experiments, casks Nos. G to 11 *. 25 Cask experiment No. 6 25 Cask experiment No. 7 28 Cask experiment No. 8 29 Cask experiment No. 9 30 Cask experiment No. 10 32 Cask experiment No. 11 33 Second series of experiments, casks Nos. 12 to 15 34 Cask experiment No. 12 35 Cask experiment No. 13 36 Ca«k experiment No. 14 37 Cask experiment No. 15 37 Specific gravity and control of fermentation 38 Comparison of analytical data 41 Notes on samples of ciders from Tables VIII and IX 43 5 THE CHEMICAL COMPOSITION OF APPLES AND CIDER. I.-THE COMPOSITION OF APPLES IN RELATION TO CIDER AND VINEGAR PRODUCTION. By Wm. B. Alwcod and R. J. Davidson. INTRODUCTION. As special work on the study of orchard problems and orchard prod- ucts has progressed, the fact has become more and more patent that for all but the most temporary results we must turn our attention more to a thorough study of elemental principles. Thus in regard to the subject in hand, the study more particularly of the fruit of the apple, it appears that without a careful and comprehensive examina- tion of the composition of the varieties of this fruit safe conclusions on many important points which govern the future of varietal selection and breeding for special purposes can not be reached. A complete study of the composition of the apple fruit would include the determination of other data than those derived solely from a chemical analysis, but a study of the physical characteristics of varie- ties has not yet been undertaken with an}^ accuracy. This is, how- ever, planned for the future, when the condition of the work and the equipment will permit. That these studies will contribute data for the guidance of students of varieties there is ever}^ reason to believe, but this will only be true when they have been brought to such tech- nical perfection that the elemental data presented can be relied upon for the making of safe deductions. Owing to the short period of time covered and the local character of the work, very few deductions are attempted in this paper. Chemistry and physics must be brought more fully to bear upon the problems of pomology, and thus aid in determining those factors which should guide us in the breeding and selection of varieties for special climatic and soil conditions. When 7 8 CHEMICAL COMPOSITION OF APPLES AND CIDER. all the factors of the problem are properly determined, who can say that the horticulturist shall not, within a reasonable time, breed apples that are more resistant to frost and to disease? As a continuation of the work begun in 1901," during 1903 a further investigation was made upon the composition of the more important varieties of apples fruiting in the experiment station orchards at Blacksburg, Va., in that year. This investigation includes the con- sideration of the quantity of juice which was secured from a given weight of each kind or variety of apple, and also a chemical analysis of both juice and pomace, so as to obtain accurate data as to the quality of the varieties and their relative value when used for the manufacture of various secondary products. PREPARATION OF THE SAMPLES. The station orchards have been described and the character and growth of the varieties sufficiently noted in bulletins Nos. 128 and 130 of the Virginia Station to render further descriptive matter under these heads unnecessary. The samples of fruit for the technical examination were selected from the trees when fully mature and placed in ordinary 10-pound grape baskets. Care was taken to select representative samples as to variations in size and to select fruit from all parts of each tree. These samples were labeled as picked and placed in a cool room, or, if nec- essary to hold them for anal^^sis, they were placed in cold storage. As far as could be determined with such a range of varieties, each one was ground when in the best condition to yield the maximum amount of juice, but in the case of a few varieties the fruit was held until decidedly overripe and mealy, and because of this fact the juice percentage is low in these varieties, which are indicated in Table I. The sample actually pulped was selected from the specimens in the basket with a view to representing fairly the individual character- istics of the fruit. Only apples free from speck or injury were used, and the stems were left on. The fruits were pulped in a machine which consists of a circular rotating basin, in which Ihe sample is placed, the pulping or chopping being accomplished by a geared device which operates a walking beam carrying a knife at one end, set so as to strike squarely on the wooden bottom of the vessel containing the fruit. When the crank is turned this machine chops or pulps the fruit very finely in the circular vessel as it rotates by a ratchet motion beneath the knife. ' While this operation is slow, it gives good results. The vessel carrying the fruit can be detached and the sample recov- o U. 8. Dept. of Agr., Bureau of Chemiatry, Bui. No. 71: A Study of Cider Making. PREPARATION OF SAMPLE. 9 ered with but slight loss. The comparatively high percentage of loss in >5ome cases may lead to a misconception. In preparing a small sample the loss shown in the table is proportionately much greater than would occur when larger quantities are handled, as this rate of loss would not continue. The tissues of the fruit are in much better condition for extracting the juice when pulped in this machine than when prepared by any small mill of the grater type which was tried. First, a small hand- grater was used, but it was found impossible to recover anywhere near the entire weight of the sample, and the fruit was so poorly pulped that the juice could not be expressed as completely as is necessary in technical work. In the machine used, however, the sample can easily be chopped too fine to give the best results under the press; therefore the desired degree of fineness should be determined before the sample is prepared. After chopping the sample as fine as desired it was carefully trans- ferred to a small hand press, known as a meat press, such as is com- monly used for pressing small quantities of substances in laboratory work. The screw was tightened slowly but very firmly until no more juice could be extracted; then the pomace was broken up and repressed as at the first operation, until it was exhausted as completely as pos sible with this apparatus. The juice so obtained and the pomace were weighed for comparison with the original sample. The samples were prepared in this manner early in the morning, and the juice and pomace were then delivered fresh to the chemical laboratory for examination before changes could well occur. Table I sets forth ir detail the results obtained in preparing the samples. Table I. — Weight and percentage of sample recovered after pulping {Blacksburg, Va.^ 1903). SUMMER VARIETIES. Variety. Sample No. Weight of original sample. Weight recovered after pulping. Percentage recovered and lost. Juice. Pomace, j Total. Juice. Pomace. Loss. Benoni 251 250 263 254 253 256 265 252 258 255 Grams. 1,814.40 1,814.40 1,814.40 2,409.75 1,814.40 1,814.40 1,856.92 3,883.95 1,814.40 2,041.20 Grams. 992.25 1,105.65 878.85 1,304.10 850.50 623.70 1,020.60 2,097.90 935.55 595.35 Grams. 737. 10 680.40 878.85 1,105.65 907.20 1,162.35 765. 45 1,587.60 765.45 1,360.80 Grams. 1,729.35 1,786.05 1,757.70 2,409.75 1, 757. 70 1,786.05 1, 786. 05 3,685.50 1,701.00 1,956.15 Per cent. 54.68 60.93 48.43 54.12 46.86 34.37 54.96 54.01 51.56 29.16 Per cent. 40^62 37.50 48.43 45.88 50.00 64.06 41.22 40.87 42.18 66.66 Per cent. 4 70 Chenango 1 67 3.14 Oldenburg .00 Red June 3 14 Sops of Wine a Summer Pearmain. . . Summer Rose Westfield 1.57 3.82 5.12 6.26 Williams J^atwite a... 4.18 Average of all.. 48.91 53.20 47.74 43.34 3.35 Average omit- ting Nos. 255 and 266 3.4C a Samples overmature when pulped. 10 CHEMICAL COMPOSITION OE APPLES AND CIDEE. Table 1. — Weight and percentdge of sample recovered after pulping {Bkuikaburg, Va.^ 1903)— Continued AUTUMN VARIETIES. Variety. Sample No. Weight of original sample. I i Weight recovered after pulping. Juice. Pomace. Total. Percentage recovered and lost. Juice. Pomace. Loss. Baltzby Buckingham Fall Orange" ... Fall Pippin Fanny Maiden Blush... Mother Moulin k Vent*. Plumb Cider.... Portera Smith Cider Tolman Sweet . . . Wealthy Average of all.. Average omit- ting Nos. 2G6 and 267 271 266 272 259 274 275 268 276 267 288 281 278 Grains. 1, 304. 10 1,360.80 1,190.70 1,474.20 1,569.25 1,360.80 1,332.45 340.20 1,332.45 1,289.92 1,289.92 1,360.80 1.360.80 Grams. 708.75 793.80 368.55 737. 10 822.15 694.57 765.45 212. 62 737. 10 467.77 652.06 680.40 680.40 Grams. 567.00 567.00 765.45 722.92 708.75 623.70 567.00 127. 57 595.36 793.80 637.87 623.70 652.05 Grams. 1,27b. lb 1,360.80 1,134.00 1,460.02 1,530.90 1,318.27 1,332.45 340. 19 1,332.45 1,261.57 1,289.92 1,304.10 1.332.45 Per cent. 64.34 58.33 30.95 50.00 52.72 51.04 57.45 62.50 55.32 36.26 50.54 50.00 50.00 Per cent. 43.47 41.67 64.28 49.38 45.45 46.83 42.65 37.50 44.68 61.63 49.46 45.83 47.91 Per 60.72 53.92 47.66 43.95 cent. 2.19 .00 4.77 .62 1.83 3.13 .00 .00 .00 2.21 .00 4.17 2.13 WINTER VARIETIES. Albemarle Pippin c, Arkansas Baldwin Belle de Boskoop . Cannon Gano Grimes Golden Jonathan Lankford Lawver Limbertwig Peck Ralls Genet Roxbury Russet | Smokehouse Via Winesap i Yellow Bellflower | Yellow Newtown Dugai. phuric. Tannin. Benoni Chenango Jersey Sweet Oldenburg Red June Sops of Wine Summer Pearmain Summer Rose Westfield Williams Favorite . Average 1.046 1.050 1.053 1.047 1.044 1.054 1.062 1.046 1.045 1.051 1.049 11.73 12.61 13.28 11.70 10.99 12.86 16.05 10.30 10.87 12.89 9.17 10.94 7.92 7.99 9.88 12.44 8.68 8.85 9.75 5.24 6.79 5.61 5.60 4.67 5.42 8.50 5.77 5.50 5.36 4.22 2.26 5.06 2.20 3.15 4.24 3.74 2.76 3.18 4.17 12.33 9.53 5.85 3.50 0.35 .29 .12 .71 .48 .29 .27 .44 .09 .29 ,33 AUTUMN VARIETIES. Baltzby Buckingham . Fall Orange . . Fall Pippin... Fanny Maiden Blush Mother Moulin k Vent Plumb Cider. . Porter Smith Cider . . Tolman Siveet Wealthy Average 1.050 13.04 10.00 6.40 3.42 0.11 1.045 11.01 9.22 7.00 2.11 .35 1.055 13.31 10.22 6.62 3.42 .37 1.049 12.22 11.27 7.14 3.92 .42 1.053 12.84 11.22 6.78 4.22 .37 1.051 12.70 9.99 6.34 3.47 .49 1.060 14.77 11.69 7.31 4.16 .27 1.061 15.77 11.00 7.27 3.54 .21 1.055 15.17 10.56 7.12 3.27 .62 1.055 14.15 9.23 6.00 3.07 .39 1.057 14.44 11.64 7.44 3.99 .52 1.055 14.27 10.86 7.05 3.62 .14 1.057 15.26 11.64 7.70 3.74 .48 1.054 13.76 10.66 6.93 3.53 .36 WINTER VARIETIES. Albemarle Pippin b Arkansas Baldwin Belle de Boskoop. Cannon Gano Grimes Golden Jonathan Lankford Lawver Limbertwig Peck Ralls Genet Roxbury Russet . . Smokehouse Via Winesap Yellow Bellflower Yellow Newtown i Average 1.056 14.00 11.09 6.62 4.25 0.45 1.056 14.14 11.64 7.90 3.35 .52 1.055 13.92 11.13 5.96 4.91 .50 1.062 16.21 12.50 6.93 5.29 .78 1.054 14.52 11.50 5.32 5.87 .32 1.056 13.92 11.32 6.96 4.14 .30 1.063 15.39 12.52 6.95 5.29 .44 1.056 14.62 11.60 7.00 4.37 .23 1.054 13.35 10.86 7.14 3.53 .41 1.057 14.42 11.27 8.10 3.01 .42 1.057 14.11 11.50 7.44 3.86 .45 1.054 13.63 10.73 6.74 3.79 .39 1.052 13.12 10.68 7.92 2.62 .36 1.065 16.91 13.20 6.74 6.14 .59 1.061 15.65 12.49 7.92 4.34 .48 1.044 10.88 8.95 7.57 1.31 .13 1.065 16.45 13.34 7.39 5.65 .42 1.049 12.46 9.77 6.62 2.99 .43 1.055 13.85 11.09 6.48 4.38 .47 1.056 14.29 11.43 7.04 4.16 .41 CRAB APPLES. English Maiden Blush Queen Choice. Red Siberian . Soulard Transcendent Whitney Average a57 070 060 070 050 s 1 062 14.17 11.60 8.60 2.85 0.47 18.56 14.78 10.00 4.56 .32 15.90 11.50 6.45 4.80 .39 17.54 11.83 9.54 2.17 .71 12.26 9.00 5.99 2 86 .67 17.09 n.9o 7.68 4.00 .70 14.16 11.39 8.27 2.96 .29 15.69 11.71 8.08 3.45 .50 a Expressed as invert sugar. &See footnote on page 15. JUICE AND POMACE. 13 Table III. — Analyses of the pomace obtained from samples given in Table I {BUtcksburg, Va., 1903). SUMMER VARIETIES. Grams per 100 grams. Variety. Moisture. Ash. Total sugar.« Invert sugar. Cane sugar. Acid, as sul- phuric. Tannin. Benoni 84.00 83.17 80.50 82.35 85.10 84.85 80.25 84.46 83.45 84.80 0.34 .39 .39 .37 .39 .41 .44 .27 .38 .33 7.82 8.69 10.50 7.27 7.00 9.57 9.60 8.45 8.33 9.40 4.62 6. 52 5.46 5.48 4.33 5.67 6.69 5.45 5.15 5.60 3.04 2.06 4.78 1.70 2.53 3.71 2.76 2.85 3.03 3.61 0.28 .41 .09 .71 .41 .31 .27 .41 .10 .39 Jersey Sweet Oldenburg Sops of Wine 0.010 Summer Rose Westfield Williams Favorite Average 83.29 .37 8.66 5.49 3.00 .33 0.010 AUTUMN VARIETIES. Baltzby Buckingham . Fall Orange .. Fall Pippin... Fanny Maiden Blush Mother Moulin a Vent Plumb Cider.. Porter Smith Cider . . TolmanSweei. Wealthy Average 82.50 0.31 8.74 6.54 3.04 0.10 83.50 .30 7.78 6.00 1.70 .35 84.30 .36 9.57 6.36 3.04 .18 85.10 .31 8.24 5.85 2.27 .41 81. 75 .37 8.37 6.17 2.09 .39 82. 65 .34 9.00 6.07 2.78 .45 79.90 .38 10.90 6.85 3.85 .16 70.25 .61 7.92 5.68 2.13 .14 80.80 .32 9.24 6.65 2.46 .59 81.35 .35 9.68 7.55 2.02 .40 80.65 .39 9.92 6.64 3.12 .50 80.60 .;« 10.03 6.36 3.49 .16 77.25 .44 9.26 6.48 2.64 .42 80.81 .37 9.12 6.32 2.66 .32 WINTER VARIETIES. Albemarle Pippin b . Arkansas Baldwin Belle de Boskoop.. Cannon Gano Grimes Golden Jonathan Lankford Lawver Limbertwig Peck Ralls Genet Roxbury Russet . . . Smokehouse Via Winesap Yellow Bellflower. Yellow Newtown b Average 81.90 0.33 9.34 5.79 3.37 0.41 81.00 .39 10.32 7.00 3.15 .50 81.40 .33 8.76 5.11 3.47 .47 78. 65 .39 10.21 5.91 4.09 .75 79.65 .36 5.19 3.65 1.46 .26 80.50 .33 8.99 5.62 3.20 .28 81.10 .23 10.26 5.50 4.52 .22 82.30 .40 10 50 6.41 3.89 .20 79.25 .30 9.28 6.36 2.77 .39 81.25 .37 9.85 7.09 2.62 .40 82.15 .38 9.40 6.36 2.89 .41 82.85 .27 10.04 6.41 3.45 .35 80.75 .34 9.40 6.99 2.29 .33 80.40 .38 11.46 5.96 5.23 .59 80.65 .39 10.68 6.02 4.43 .50 84.65 .34 8.01 6.87 1.08 .14 79.15 .43 9.05 7.09 1.86 .41 79.00 .41 8.09 5.43 2.53 .41 82.00 .34 8.76 6.02 2.60 .46 80.98 .35 9.34 6.13 3.10 .39 CRAB APPLES. English.. . .. 76.40 76.65 77.35' 90.00 77.40 38.05 80.15 0.41 .49 .57 .62 .31 .43 .52 10.15 11.76 10.09 11.52 7.33 10.36 10.58 5.84 7.78 5.85 10.15 5.06 5.70 7.62 4.09 3.78 4.03 1.30 2.16 4.43 2.81 0.31 .35 .47 .75 .63 .73 .31 0.091 Maiden Blush .063 Queen Choice .164 Red Siberian . . . Soulard .190 Transcendent j Whitney Average 70.85 .48 10.25 6.85 3.23 .51 .127 a Expressed as invert sugar. ft See footnote on page 15. 14 CHEMICAL COMPOSITION OF APPLES AND CIDER. The chemical composition of American apples has been studied so little up to the present time that there is not much material for com- parison. In Bulletin No. 71 of the Bureau of Chemistry, issued in 1903, the data then available on the subject were collected, and no special work of this nature has been published since, so far as can be ascer- tained. The data herein presented comprise, therefore, the greatest number of analj^ses of varieties that has yet been made in any one season and include a considerable number of varieties commonly grown in the United States. This report necessarily lacks the conclusive- ness which attaches to a work covering a series of years, but takes its place merely as a contribution to the solution of the problem under consideration. In connection with the average composition of the apple must shown by these analyses it is interesting to compare them with the averages obtained in some previous work done on American apples, as given in Table IV. Table IV. — Average composition of apple musts {compiled). Analyst. Specific gravity. Solids. Total sugar. Reducing sugar. Cane sugar. Acid, as sulphu- Tannin. Browne, Pennsylvania Exper- iment Station, 1899 1.05523 1.053 1.059 1.0535 Per cent. 13.36 12.19 13.98 13.39 Per cent. 11.94 9.58 10.88 10.45 Per cent. 7.78 6.78 7.00 6.84 Per cent. 3.76 2.65 3.68 3.48 Per cent. 0.453 .35 .42 .37 Per cent. Davidson, Virginia Experi- ment Station, 1901 0. 022 Davidson, Virginia Experi- ment Station, 1901 (crab) ... Burd, U. S. Department of Agriculture, 1901 .060 These averages bear a close relation to the results given in, the pre- ceding tables when it is remembered that the figures for summer varieties can not properly be compared with results on winter fruits. The gradual increase in solids and total sugars in passing from sum- mer to fall and winter varieties supports in a way the well -recognized facts as to their quality, but these diflferences are much less striking than one would expect when the averages are considered. The indi- vidual variations, however, of the several varieties of any given season, as compared with each other, are far more important, and what is also more to the point, these variations clearly indicate qualit3^ For example. Summer Pearmain, the high rank of which is con- ceded, shows 16.05 per cent of total solids and 12.44 per cent of total sugars (Table II), the highest result of any summer or fall variety. The analysis of Jersey Sweet, one of the good varieties of its season, shows a relatively high per cent of total sugar, and in cane sugar surpasses all of the summer and fall varieties, but it has a low acid content. The low sugar content of Red June and Oldenburg is very striking, and the latter is the poorest in cane JUICE AND POMACE. 15 sugar of the early varieties. The low acid content of Westfield is in striking contrast with most of the other summer varieties and reveals a real defect in the quality of this fruit. The fall varieties show decidedly less variation of sugar content than the summer or winter sorts, and yet the average sugar content is about 1 per cent higher than in the early varieties. Fall Pippin and Maiden Blush are striking examples of well-balanced analyses as to reducing and cane sugar and acid content, and thus the standard quality of these fruits is explained. Fanny and Mother sustain their claim to be classed among the best varieties, and here the analysis points to the high content of cane sugar as the probable explanation of their fine quality. The acid content of the fall fruits averages low, as is the case with the summer varieties, but the high percentage shown in Plumb Cider and Smith Cider is distinctly correlated with characteristic quality. The analj^ses of the winter varieties average about the same as the results'quoted from Browne in Table IV. The composition of each of the 19 varieties is fairly uniform in the majority of cases, but a remarkable contrast is shown by the extremes. Via and Roxbury Rus- set. The sugar content of the latter is remarkably high, and the analysis so well balanced between sugars and acid that the splendid quality of the fruit is well explained. The cane-sugar content, 6.14 per cent, is the highest found for the entire series analyzed. The physical characteristics of this fruit and its chemical composition doubtless explain its good keeping qualities, even when grown as far south as Blacksburg, Va. Grimes Golden^ Smokehouse, and Winesap all give analyses which mean much as to their fine quality and value as parent stocks for future selection. The latter has the highest total sugar content of all of the varieties analyzed, and has a well-balanced sugar and acid content. Belle de Boskoop, a coarse-fleshed apple, which apparently has little to recommend it, compares favorably with these better varieties in analysis and exceeds some of them in its con- tent of cane sugar. This apple is apparently the one striking excep- tion to the relation found to exist between quality and chemical com- position, and its objectionable characteristics are physical rather than chemical. Attention should be called to the two analyses of pippins. For fif- teen years the Albemarle Pippin^^ as propagated in Albemarle County, and the Yellow Newtown,'* as propagated in New York, have been grown at the Virginia station. The differences between the two and the points they have in common have been noted in the Virginia station a The name Albemarle Pippin is considered by pomologists to be a synonym of Yellow Newtown, which is the recognized name of the variety. The analytical and other data concerning the two are given separately in the tables in order to show their similarity. 16 CHEMICAL COMPOSITION OF APPLES AND CIDER. bulletins.^ The analyses of the apples are so nearly alike that they are worthy of special note. From these analyses it appears probable that the high quality of these apples depends not so much upon actual sugar content as upon the well-balanced percentages of sugars and acid, and the physical peculiarities of the flesh of the fruit. The variety Moulin a Vent is a French scion grafted on Chenango. In discussing the French varieties in Bulletin No. 71* allusion is made to the peculiar qualities and richness in sugar of the French cider apples. Many scions were brought from France and are now grow- ing at the Virginia station, and this one is the first of them to fruit. It bore the characteristic fruit observed in France, but the analysis of the juice shows only 11 per cent of sugar, whereas the French anal- yses of this variety run as high as 16.57 per cent. The interesting question is thus raised, Will these French varieties fail to produce as rich juice in this country as in France? The tannin content is also lower than shown b}^ the French analyses, but is higher than in any of the American varieties except some of the crabs. Of the crabs Maiden Blush shows a remarkably good analysis, and the practical work done has clearly proved that this vai i \v is one of the most desirable for canning and jelly making. From the data brought together by these analyses it would seem that an investigation of the composition of apples covering suflScient material and a suitable period of time will reveal facts of the utmost importance to the pomologist and also to those who use this fruit in factory work. It does not appear to have been heretofore recognized what an important part the cane sugar may possibly play in the quality of the apple. The analysis of the pomace is important principally because it enables us to express clearly the loss which may occur if the pomace is not utilized in such a manner as to recover these substances. At the custom mills in the United States it has been the usual practice to deposit the pomace where possibly a little of it may be eaten by stock, but on the whole it is practically treated as waste. It will doubtless surprise many people to learn what a large amount of sugar is lost in the pomace. This point is brought out in Table V. a Virginia Agr. Exp. Sta. Buls. Nos. 128 and 130. &U.-S. Dept. of Agr., Bureau of Chemistry: A Study of Cider Making. JOICE AND POMACE. 17 Table V. — Sugar and acid content calculated to the whole fruit from Tables I, II, and III {calculated at the Bureau of Chemistry) . SUMMER VARIETIES. Variety. Grams per 100 grams. Total sugar. Invert sugar. Cane sugar. Acid as sul- phuric. Total sugar re- covered in juice. Total sugar re- covered in pom- ace. Benoni Chenango Jersey Sweet Oldenburg Red June Sops of Wine Summer Pearmain Summer Rose Westfield Williams Favorite . Average . 8.87 8.97 10.70 7.61 7.47 9.67 11.21 8.56 8.60 9.49 4.96 6.67 5.52 5.54 4.48 5.57 7.71 5.61 5.33 5.52 3.70 2.17 4.91 1.97 2.81 3.88 3.30 2.79 3.09 3.76 0.31 .32 .09 .70 .42 .28 .25 .41 5.29 5.58 5.29 4.28 3.74 4.68 4.56 2.84 9.11 3.23 ,32 4.64 3.17 3.25 5.08 3.33 3.50 6.13 3.95 3.45 3.51 6.26 4.16 AUTUMN VARIETIES. Baltzby Buckingham . Fall Orange . . Fall Pippin... Fanny Maiden Blush Mother Moulin a Vent Plumb Cider. . Porter Smith Older. . . Tolman Sweet. Wealthy Average 9.42 6.00 3.24 0.09 5.43 3.79 8.61 6.58 1.93 .34 5.37 3.24 9.77 6.42 3.15 .23 3.16 6.15 9.75 6.49 3.09 .41 5.63 4.06 9.89 6.48 3.21 .36 5.91 3.80 9,50 6.20 3.13 .46 5.09 4.12 11.34 7.10 4.02 .21 6.71 4.63 9.84 6.67 3.00 .18 6.87 2.97 9.96 6.90 2.89 .60 5.84 4.12 9.50 6.96 2.40 .38 3.34 5.95 10.78 7.04 3.55 .50 5.88 4.90 10.45 6.71 3.54 .14 5.43 4.59 10.47 7.09 3.19 .44 5.82 4.43 9.94 6.66 3.10 .33 5.42 4.36 WINTER VARIETIES. Albemarle Pippin . Arkansas Baldwin Belle de Boskoop. Cannon Gano Grimes Golden Jonathan Lankford Lawver Limbertwig Peck Ralls Gend .'! Roxbury Russet . . Smokehouse Via Winesap Yellow Bellflower Yellow Newtown Average — 10.32 6.25 3.86 0.42 6.00 3.89 10.98 7.45 3.24 .51 5.82 5.16 10.06 6.57 4.25 .48 6.11 3.95 11.49 6.48 4.76 .75 6.83 4.23 8.86 4.62 4.02 .28 6.70 2.16 10.02 6.20 3.61 .28 4.95 4.86 11.28 6.15 4.87 .30 5.65 5.42 10.99 6.66 4.10 .20 5.31 5.46 10.21 6.81 3.21 .39 6.44 3.77 10.61 7.63 2.83 .40 6.10 4. 51 10.45 6.90 3.37 .42 5.75 4.70 • 10.40 6.57 3.63 .37 5.77 4.63 10.07 7.47 2.46 .33 4.57 3.45 12.23 6.30 5.62 .58 5.86 6.15 11.66 7.05 4.37 .48 6.81 4.85 8.47 7.22 1.18 .12 4.47 3.83 11.60 7.26 4.10 .40 7.78 3.58 9.13 6.16 2.80 .41 6.10 3.03 10.04 6.26 3.57 .46 6.00 3.83 10.46 6.57 3.67 .39 5.94 4.28 CRAB APPLES. English Maiden Bhish Queen Choice. Red Siberian . Soulard Transcendent Whitney Average 10.93 7.32 3.41 0.39 6.28 4.65 13.58 9.11 4.24 .32 8.93 4.65 11.02 6.24 4.54 .41 7.66 3.36 11.67 9.83 1.73 .72 6.02 6.65 8.30 5.59 2.55 .63 5.06 2.90 11.27 6.88 4.16 .70 7.09 4.18 11.02 7.97 2.88 .29 6.05 4.46 11.11 7.56 3.35 .49 6.72 4.26 6390— No. 88—04- 18 CHEMICAL COMPOSITION OF APPLES AND CIDER. From Table V, giving the sugar and acid content of the whole fruit, it is at once seen that the total sugar for the whole fruit is not on the average so high as the total sugar in the juice (Table II), but is a little higher on the average than the sugar found in the pomace (Table III). Also, the cane sugar of the whole sample is proportionately lower than the cane sugar found in the juice. This would indicate that the juice extracted by grinding and pressing is relativel}^ richer than that which remains in the pomace, and that the cane sugar is also secured propor- tionately in larger percentage than that in which it actually exists in the original fruit. The actual quantities of sugar recovered in the juice and pomace are given in grams per hundred grams of whole fruit in this table. These two columns do not represent the total sugar, except when there was no loss of sample. This loss was not proportionately distributed between the two columns, the compari- son being deemed more reliable as presented than if the lo^s were so distributed. The last column in Table V gives the percentage of sugar actually recovered which is left in the pomace. This percentage will become rapidly less as the proportion of the original weight of fruit recovered as juice increases, and therefore the question of improved methods of grinding and pressing is a very important one. It does not appear up to the present time that the American manufacturers have solved the question of recovering, in a practical manner, this comparatively large waste which ordinarily is lost in the pomace. There is, however, a simple but rather expensive method of recovering the valuable con- stituents of the pomace b}^ exhaustion with warm or cold water, pre- ferably the former. This may be accomplished, in tubs or casks or in regular diffusion batteries, such as are used in sugar factories. The weak must or juice thus recovered may be used to dilute richer juice intended for vinegar stock. Pomace can also be used in the silo if mixed with leguminous crops or corn, and its feeding value is thus successfully conserved and utilized. DRY MATTER AND MINERAL CONSTITUENTS. For these determinations only a few varieties of standard value were selected. These appear to give a fair range of fruits for the several seasons, except in case of the earliest varieties. It was intended to include Early Ripe and Oldenburg in this list, but these were out of season before the work could be imdertaken, and therefore it can not be said to represent the probable variations in composition which will be found in the very early varieties. The complete analysis of a large number of varieties of apples involves so large an amount of work that it was decided not to attempt complete analyses of any of the varieties in the strict sense of this term. The preceding tables cover quite fully those substances of direct importance to quality and com- DRY MATTER AND MINERAL CONSTITUENTS. 19 mercial value of a large number of varieties. The analyses presented in Table VI include the determination of nitrogen, phosphoric acid, potash, and lime. The standard list of varieties examined for these constituents was selected with a view to continuing the chemical examination of fruit from these same trees for a series of years, thus establishing the normal content of these important elements. Such determinations, together with the crop statistics from the same trees, will give in time most valuable data for the guidance of cultural practice. There is at present little to be gained by deductions which could be made from the work of this one season. Table VI — Determination of moisture, solids, ash, and the more important mineral constituents in whole fruits {Blacksburg, Va., 1903). SUMMER VARIETY. Grams per 100 grains. Variety. Moisture. Solids. Nitrogen. Ash. Phos- phoric acid (P2O5). Potash (K2O). Lime (CaO). Jersey Sweet 82.81 17.19 0.060 0.29 0.056 0.190 0 020 AUTUMN VARIETIES. Buckingham 88.85 86.96 11.15 13.04 0.060 .030 0.20 .24 0.018 .014 0.110 .120 0 008 Maiden Blush .005 Average . . 87.90 12.09 .045 .22 .016 .115 0065 WINTER VARIETIES. Albemarle Pippin Arkansas Black . Cannon Gano Grimes Golden... Peck Winesap Average 85.67 14.33 0.060 0.25 0.026 0.140 86.48 13.52 .041 .34 .020 .230 83.99 16.01 .082 .26 .026 .150 86.01 13.99 .059 .23 .022 .120 84.69 15.31 .060 .25 .028 .143 86.11 13.89 .042 .20 .018 .120 84.70 15.30 .049 .31 .018 .180 85.38 14.62 .056 .26 .023 .155 0.009 .006 .009 .012 .010 .007 .010 .009 CRAB APPLES. Maiden Blush 81.64 84.03 18.36 15.97 0.060 .064 0.37 .36 0.022 .030 0.220 .180 0.012 Transcendent .007 82.83 17.16 .062 .365 .026 .200 .0095 II.-THE COMPOSITION OF CIDER AS DETERMINED BY DOMI- NANT FERMENTATION WITH PURE YEASTS. By Wm. B. Alwood, R. J. Davidson, and W. A. P. Moncure. WORK OF 1901-2. INTRODUCTION. In the autumn of 1901 a series of experiments upon the manufacture of ciders with pure yeast cultures was begun at the Blacksburg station in cooperation with the Bureau of Chemistry. The apple must or juice used for this experiment was made with the power mill belonging to the station from ordinary mixed apples, mostly of inferior varieties. Immediately after pressing, the juice was placed in sound, clean, 50-gallon casks, and these were at once bunged to prevent further access of organisms to the juice until it could be sown with yeast. These casks, or 50-gallon barrels, were placed on the second floor of the factory building and were sown with yeast cultures about three hours after grinding the fruit. In these experiments, which were made on a scale comparable with commercial work, the juice or must was not sterilized or pasteurized before sow- ing with the pure j^east cultures. While the destruction by use of heat of the many microscopic organisms always present in fresh fruit juice is practicable, even on a large scale in factory work, as yet it has not been found to be desirable for commercial ciders. Heating the must causes such changes in the flavor that the most careful cellar work and use of pure ferments has failed to counteract this effect, and thus the fine natural flavors are quite commonly injured by attempts at sterilization. Control or dominant fermentation is easily secured if one sows a sufficient amount of fresh culture of a strong yeast into the newly made must. The question of the relative activities of the pure fer- ments in comparison with mixed 3^easts and "wild" ferments in steril- ized and unsterilized nmst will be treated in a subsequent paper which will deal more specifically with the ferment organisms. The station is without suitable cellars or fermentation rooms, and therefore this work was done under such varying conditions of temperature that the 20 WORK OF 1901-2. 21 best results could not be anticipated; yet the experiment was, all things considered, a success. Several other experiments were under- taken in the autumn of 1901, but only two are reported, because the other tests were made in large casks purchased from an old wine cellar which were in such bad condition that they could not be properly cleansed, and the experiments failed. The two experiments here reported were carried on in the 50-gallon casks above mentioned. Bulletin No. 71, Bureau of Chemistry, treats of the general and theo- retical considerations in cider making; hence these phases of the ques- tion are not discussed again in this report. CASK EXPERIMENTS NOS. 2 AND 3. The plan of the experiment was very simple. The must or juice was taken from the same vat and came from one bulk of fruit; it was divided among several casks, and sown with different yeast races at the same time. Thus the results produced by these yeasts could be com- pared, as the same must was handled under identical conditions, the only variant being the yeasts. The experiment was begun on September 24, 1901, on which date casks Nos. 2 and 3 were filled with juice freshly expressed. This juice tested on the h3^drometer 1.050, which would indicate a sugar content of 10.15 per cent. A full analysis was not made. At 3 o'clock p. m. of the same day these barrels were sown as follows: No. 2 with a pure culture of about 1 pint of sterilized cider, which had been inocu- lated with Sauterne yeast, known in the station laboratory as No. Y3. Cask No. 3 was inoculated with about 1 pint of a pure culture made from Vallee d'Auge yeast, known as No. 74. Both cultures were sown when in full vigor and grew promptly, dominating the entire fermentation. The Sauterne yeast. No. 73, was isolated from French Sauterne wines, and No. 74 from cider from the famous Vallee d'Auge cider country in Normandy, France. After inoculation both barrels were stoppered with vents which permitted the escape of the gas formed in the barrels and yet prevented the entrance of extraneous organisms from the air.'^ The casks were sown with this considerable quantity of an active yeast culture in order to secure the prompt growth of a pure yeast in each cask before the ordinary " wild " organisms present in the juice could grow and take possession of the fermentation. A microscopic examination of small samples of liquor removed from the casks, made each day from September 25 to 28, showed an abundant growth of pure yeast with apparently no occurrence of deleterious organisms. By the afternoon of September 26 both casks were in full fermenta- «A discussion of this device is given in Bulletin No. 71, Bureau of Chemistry, U. S. Department of Agriculture, pp. 82 to 86. 22 CHEMICAL COMPOSITION OF APPLES AND CIDER. tion and gas was issuing from the vents. On the morning of Septem- ber 27, at 9 o'clock, the temperature of the liquor in barrel No. 2 was 56° F., and in barrel No. 3, 57° F., the fermentation proceeding in a rather turbulent manner. On September 28 both casks Avere ferment- ing in an orderly manner and the microscopic examination showed the development of a slight growth of the false 3^east form known as Api- culatiis, but the great majority of the organisms were a pure yeast growth. The temperature of the room where these casks were stored varied, perhaps, from 60^ to 80° F. , as the recorded outdoor tempera- tures show maximums ranging from 53° to 79° F. and a mean of 51° F. Daily examinations of the must to determine the organisms present were continued, with the result that the 3^east growth was found to be entirely dominant. On October 4 the first fermentation was plainly subsiding; on October 8 both barrels had become practically quiet. The liquor in cask No. 2 was opalescent in color, not bright, had a fairly good head over the top, and no pomace in the juice. The taste was pleasant and fruity, and the cider seemed to be completing the first fermentation in a perfectly sound and promising condition. It was on this date racked off into a well-sulphured, clean barrel, and tightly bunged with the ventilating device before mentioned. On this date a chemical analysis was made of cask No. 2, which gave the following results: Specific gravity 1. 026 Total solids grams per 100 cc. . 6. 80 Sugar do 4.82 Alcohol do 2. 76 Acid as sulphuric do 43 The liquor in cask No. 3 was brighter than that in No. 2 and showed practically no head on the liquor. The cider had a slightly unpleas- ant flavor, differing in taste from No. 2. This barrel also was racked into a clean sulphured barrel, and a chemical analysis was made of the partially fermented cider with the following results: Specific gravity 1. 020 Total solids grams per 100 cc. . 5. 72 Sugar do 4. 16 Alcohol do 3. 21 Acid as sulphuric do 50 Both casks were left lying side by side on the upper floor of the factory, and after racking repeated observations were made upon the condition of the cider until November 23^ A slight difference could be observed during the entire time of the second fermentation in these two casks, yet both remained in a perfectly sound condition, and the microscopic examination after racking off showed the presence of only yeast organisms. There was apparently no growth whatever of the vinegar ferment or other deleterious organisms in these barrels. WORK OF 1901-2. 23 On November 23 both barrels were bottled. A mixed collection of wine, apollinaris, and other somewhat nondescript bottles was used. These were all carefully cleansed with hot water and sterilized by rinsing with 35 per cent alcohol before tilling. The corks were also sterilized by dipping in alcohol. This precaution was taken to pre- vent, as far as possible, the growth of such malorganisms as might be present, the casks having been kept under conditions favorable to the growth of malferments, and it was now desired to mature the cider in bottles. On the date of bottling a sample was taken from each cask, which gave the following analyses: No. 2: Specific gravity 1 1. 006 Sugar grams per 100 cc. . 1. 16 Alcohol do.-.. 4.68 Acid as sulphuric do 48 No. 3: Specific gravity 1. 003 Sugar grams per 100 cc. . .27 Alcohol do 5. 36 Acid as sulphuric do 55 After tilling the bottles they were carried into a small cellar under the office buil^ling, laid down on the side, and left for further ripening of the cider. Both samples continued to ferment in the bottle, and the following notes were made on the changes which occurred: NOTES. December W^ 1901. — No. 2 was a clear amber liquor, with a rather yellowish tinge and a decided deposit of yeast cells. No. 3 had a beautiful, clear, bright amber color, with a very slight deposit, which seemed to be coagulated. Januai'y 20^ 1902. — The bottles from No. 2 contained a bright, clear amber liquor, with a fine, uncoagulated sediment. The liquor had become gaseous, and showed a transient but decided effervescence when poured into a glass. The flavor was good, with a tine bouquet. The chemical analysis at this time was as follows: No. 2: Specific gravity J 1 . 007 Total solids grams per 100 cc. . 2. 87 Sugar do 1. 02 Alcohol do 4. 44 Acid as sulphuric do 36 Thus it would appear that the alcohol and acid content of the cider declined slightly during this period of ripening in the bottle, and the sugar, as would be expected, also declined, but only to a small extent, while there was a fairly active growth of yeast, indicating that this growth was somewhat at the expense of alcohol and acid. On the same date (January 20) No. 3 was examined. The liquor 24 CHEMICAL COMPOSITION OF APPLES AND CIDER. was very bright, but rather paler in color than No. 2. The sediment was coagulated, but light and llocculent. There was no gas and the liquor was perfectly still on pouring. The cider was of good flavor, without roughness, bouquet faint, having the general characteristics of a sour claret wine. The analysis made on this date was as follows: No. 3: Specific gravity 1. 003 Total solids grams per 100 cc. . 2. 33 Sugar do 30 Alcohol do 5. 09 Acid as sulphuric do 53 January ^If. to May 16. — The stock from both tests was rebottled by decanting, so as to clear the liquor of the sediment mentioned. The bottles used were prepared and cleansed as above stated and the corks were also sterilized. After this date observations were made at inter vals until May 16, 1902, when the last notes were made on No. 2. Though it had been rebottled, the liquor was bright and sparkling, slightly gaseous when poured, aroma very good, flavor excellent and free from roughness, and of a bright amber straw color. The analysis of No. 2 made at this time gave the following results: No. 2: Specific gravity 1. 004 Total solids grams per 100 cc. . 2. 60 Sugar do 98 Alcohol do 4.43 Acid as sulphuric do 35 There was considerable sediment present in the bottles again, due to after-fermentation. The sugar, acid, and alcohol had remained almost constant, but there had been sufficient fermentation to slightly charge the cider. It was at this time pronounced by several who sampled it to be one of the finest ciders they had ever tasted, and equal to some grades of sparkling wine. May 22. — No. 3 was given its last examination at this time. Though it had been rebottled as above stated, the liquor had become slightly gaseous, and showed an evanescent but decided effervescence in the glass; the color was a clear pale amber; the aroma very fine, fruity in qual- ity, making altogether an excellent dry cider. While No. 2 had the character of a sparkling wine, this cider differed from it very decid- edly, having, after the disappearance of the slight effervescence, more the character of a Graves wine. The chemical analysis of No. 3 made at this time gave the following results: No. 3: Specific gravity 1.003 Total solids grams per 100 cc. . 2. 24 Sugar do 20 Alcohol do 5.20 Acid as sulphuric do 48 WORK OF 1903-4. 25 The great difference observed in the character of these two ciders is borne out by a comparison of the analyses, and yet they were made from absolutely the same juice and handled alike in every particular, the yeast cultures alone being different. Both ciders were of remark- ably good quality, but No. 2 was more to the average American taste, while No. 3 was considered the best by those who prefer a light, dry, sour cider. WORK OF 1903-4. No experiments were undertaken in the fall of 1902, because the fruit crop was so small that no stock could be obtained, but in the fall of 1903 a rather extensive series of cask experiments was again instituted, the more successful of which are here reported. FIRST SERIES OF EXPERIMENTS, CASKS NOS. 6 TO 11. These six experiments were all begun the same day and conducted as described in the following notes: Septemher 30, 1903. — The ordinary mixed stock of cider apples was ground in the power mill at the station and six 50-gallon casks were filled with the fresh must of identical character and transferred to a small cellar under the garden tool house, where they were sown with yeasts as specified in the reports on each cask. The casks were care- fully cleansed with washing powder, scalded with a steam hose from the boiler, and then thoroughly rinsed with cold water before- filling. A chemical anal^^sis of the must fresh from the mill was made with the following results: Stock must: Specific gravity 1. 051 Total solids grams per 100 cc. . 13. 04 Sugar (total) do. ... 10. 08 Sugar ( reducing) do 7. 31 Sucrose do 2. 63 Acid as sulphuric do 49 Tannin do.. . .05 Cask Experiment No. 6. Cask No. 6 was sown on September 30, as soon as placed in the cel- lar, with one pint of must which had been sterilized and sown with yeast No. 8 on September 25, and was in full fermentation when used. The cask was plugged with a cotton plug, and later the ventilating tube was used as in the experiments of 1901. Yeast No. 8 was.isolated from a very good Normand}^ cider obtained at the factory of the Union Agricole at St. Ouen-de-Thouberville, France.'* «Thi8 yeast was isolated by Mr. Alwood while working at Geisenheim, Germany. 26 CHEMICAL COMPOSITION OF APPLES AND CIDEB. NOTES. Gellar conditions. — The general cellar conditions here noted will not be repeated for the other numbers of this series, as the casks stood side by side and were handled exactl}^ alike. Octoher 1. — Fermentation under way and foam forming on liquor; temperature of must in barrel 66° F. ; temperature of rot)m 64° F. October 2. — Fermenting slowl}^; temperature of room 62° F. October 3. — Fermenting more slowly than the day before; tempera- ture of room 60° F. October Jf,, — Fermenting more vigorously; temperature of room 62.5° F. October 5. — Temperature of room 62° F. October 6. — Temperature of room 61° F. October 7. — Temperature of room 62.5° F. October 8. — Temperature of room 59° F. October 9. — Temperature of room 55° F. October 10. — Liquor in cask ochreous-yellow and turbid; indications of rapid sedimentation and subsidence of first fermentation; ordinary fermenting cider taste; no marked difference between the several experiments. Specific gravitv of No. 6, 1.012. Microscopical exami- nation shows yeast to be small, ovoid, apparentl}^ pure; no head on liquor; room temperature 30° F. ; temperature of liquor in cask 57° F. ; fermenting quietW. A decided cold spell ran the temperature of the room down sharply at this time. October 20. — Fermenting slowly; slight foam resting on liquor. Temperature of the must 52° F. ; liquor very cloudy and tastes of tannin; no aftertaste; cellar temperature 52° F. The first head has fallen and the after fermentation set in. October 25. — Liquor of an opalescent amber color, clearer than at any previous date, and condition good; cellar temperature 48° F.; temperature of must 49° F. October 27. — Sent to laboratory for partial analysis. Specific grav- ity, 1.004; alcohol, 4.76 grams, and sugar, 0.46 gram per 100 cc. October ^5.— Racked into a thoroughly clean, sulphured barrel; siphoned the liquor off to within 3 inches of the bottom of the barrel; temperature of the cellar 48° F. It will be seen by reference to the discussion of fermentation in Bulletin No. 71 " that practically the German method of fermentation was pursued in this instance instead of the French method of racking after the subsidence of the first or tumultuous fermentation, which was followed in 3 901 with casks Nos. 2 and 3. By the German method the sugar is practically exhausted before the first racking. It is a simple method, but can not, in the estimation of the authors, produce a cider which is equal in fine char- acter to that secured by the French method. a U. S. Dept. of Agr., Bureau of Chemistry, A Study of Cider and Cider Making, p. 102. WORK OP 1903-4. 27 November 6. — Temperature of room 38° F. Novemher 9. — Temperature of room 46° F. Novemher 19. — Liquor pale straw color, fairly clear, but not bright; aroma mild and fruity; flavor mild. Specific gravity, 1.002. December ^22. — Bottled 75 quarts and removed to the cellar under the office building. The bottles in all experiments were laid flat. Liquor fairly clear, but not absolutely bright; flavor ver}^ good; aroma mild. The remainder of the liquor was left in the cask, properly bunged. January <5, 190 Ip, — Specific gravity of cider in cask, 1.002; temper- ature of cellar for some days has been below 35° F. January 11. — Chemical analysis of cider in cask gave the following results: Specific gravity 1 . 003 Solids grams per 100 cc. 1.97 Sugar do 38 Alcohol do 5. 35 Acid do 49 January '25. — The cider remaining in the cask was drawn off without agitating and filtered through a gravity filter with a 10-foot fall. Liquor in fine condition; a little clouded in the barrel in comparison with the filtered cider, which is very bright, leaving nothing to be desired. It was found necessary to use one cloth and one paper disk to produce the desired result in the filter. The stock was bottled immediately from the filter in apollinaris bottles, then placed in the small cellar under the office building. January 25. — The cider bottled on December 22 and placed in the cellar now shows a dirty, flocculent sediment. It is not, therefore, a first-class cider in appearance, but on sampling the liquor is found to be of a clear, amber color, not exactly bright; the aroma rich and fruity, and the flavor excellent — a fine dry cider. April 19. — First bottling: Liquor fairly clear; straw color; heavy dark sediment; strongly gaseous; bubbles persistent; aroma good; flavor mild and desirable. Second bottling: Liquor clear; fairly bright, pale straw color; streak of yeast on lower side of bottle, but not sufficient to interfere with marketing; slightly gaseous; good bead; fruity aroma; flav^or good, but slightly rough. May 9. — Second bottling: Color light amber; a little cloudy; slightly gaseous; odor pleasant; dry, sound; flavor a little acid. The filtered stock was not further noted as the samples were lost. May 25. — First bottling: Liquor dull, lacks brightness in the bottle; a considerable quantity of coagulated sediment present; decidedly gaseous; pours fairly bright, sparkling; bouquet fairly strong and 28 CHEMICAL COMPOSITION OF APPLES AND CIDER. very fruity; of a clouded straw color; flavor fairly smooth, sound, and slightly acid; medium as to quality. Chemical analysis as follows: Specific gravity 0. 999 Solids grams per 100 cc. . I. 79 Total sugar do trace. Alcohol do .... 5. 66 Acid do 33 Tannin do 049 This cider, made on the German system of inclusive fermentation, proved to be a fine, sound, apple wine, but its character when thus reduced to complete dr3^ness (all sugar consumed by fermentation) is not generally pleasing to the American taste. After using it some time, however, it is well liked, and as long as the gas generated after bottling is not permitted to escape the cider will remain sound. Cask Experiment No. 7. The chemical analysis of the original must and also the notes on the cellar temperature throughout the experiment, as given under cask experiment No. 6, are true for the entire series, and are not repeated. This 50-gallon barrel was sown on September 30, 1903, with yeast No. 37, which culture had been prepared in the same quantity and manner as for cask No. 6. The barrel was at once plugged with cotton wool, and later fitted with the vent before men- tioned. Yeast No. 37 was isolated by Mr. Alwood from the same source as No. 8. It is an especially strong yeast, and can be trusted to carry fermentation to completion promptly. NOTES. October 1. — Heavy foam already formed; gas in barrel extinguishes a taper promptly ; the must shows temperature of ^^"^ F. October 2. — In rapid fermentation. October 3. — Fermenting more slowly. October 10. — Note as to condition same as for test No. 6; specific gravity, 1.019. Microscopic examination shows an abundance of small ovoid yeast cells; fermentation progressing quietlj^; no head on bar- rel; temperature of must, 57° F., the same as No. 6. October W. — Liquor very cloudy; flavor pleasant; no bitter taste; specific gravity, 1.007. October 27. — A partial analysis showed a specific gravity of 1.006; total sugar, 0.96, and alcohol, 4.61 grams per 100 cc of cider. October 28. — This cask was racked as in case of No. 6. Novemher 19. — Liquor pale straw color; fairl}^ clear, but not bright. Aroma good; flavor very good; specific gravity, 1.004. January 23, 1904-^ — Specific gravity, 1.005. WORK OF 1903-4. 29 January ^5. — A complete analysis gave the following results: Specific gravity 1 . 004 Solids grams per 100 cc. . 2. 48 Sugar do .64 Alcohol do 5. 28 Acid do 43 Tannin do 041 January 28. — Bottled 75 quarts. The cider was filtered through a gravity filter, as in the case of cask No. 6, which left it fairly bright and clear. The remainder of the cider was left in the cask and bunged tightly. The color at this time was pale amber; aroma fruity; flavor good, that of a sound dry cider. April 19. — The cider in the bottles was rather dull, with a strong yeast deposit, cloudy when shaken; decddedly gaseous; pours with good bead; fine bouquet; flavor slightly rough, but equal to No. 6. This barrel was also handled on the German plan of cellar work, and the results indicate that while this plan produces a fine, sound, dr}^ cider, it does not bring out those special qualities to be expected from the use of selected yeasts. Cask Experiment No. 8. The general notes are the same as for cask experiment No. 6. Cask No. 8 was sown on September 30, 1903, with 1 pint of yeast culture No. 66, prepared as for No. 6. Yeast No. 66 was isolated from a specially fine Pippin cider ten years old, procured from Huntington, Long Island, New York. NOTES. October 1. — Already in active fermentation; heavy foam resting on liquor, but air in barrel will still support flame; temperature of must, 66" F. October 2. — Fermenting rapidly. October 3. — Fermenting more slowly. October 10. — Note as to condition same as for test No. 6, except that taste is a trifle inferior; specific gravity, 1.019. Microscopic exam- ination shows yeast numerous, large, and round. No head on liquor; temperature of the must, 57° F. October 20. — Note as to condition same as test No. 6; specific grav- ity, 1.008. Octoben' 27. — k. partial anal3^sis gave a specific gravity of 1.005; alcohol 5.24: and sugar 1.28 grams per 100 cc of cider. October 28. — Racked as in case of test No. 6. November 19. — Liquor pale straw amber, fairly clear, but not bright; aroma very good; flavor very good; specific gravit}^ 1.004. January 23, 1904- — Specific gravity, 1.002. 30 CHEMICAL COMPOSITION OF APPLES AND CIDER. January 25. — Analysis gave the following results: Specific gravity 1. 003 Solids grams per 100 cc. . 2, 64 Sugar .• do 90 Alcohol do 6. 00 Acid do 39 Tannin do 034 January 28. — Bottled 75 quarts under same conditions as for test No. 7. Liquor slightl}^ clearer than No. 7, not bright, pale amber; aroma rich and fruity; flavor very good — a fine dry cider. Apivl 19. — Liquor bright and beautiful; slight yeast deposit; not flocculent; bouquet good; flavor mild; a good, sour, still wine. This is the most promising American yeast isolated. Cask Experiment No. 9. General notes the same as on cask experiment No. 6. Cask No. 9 w^.s sown with 1 pint of j^east culture No. 73, prepared as previously described. The barrel was plugged with cotton wool at once, and later closed with the ventilation apparatus. The origin of 3^east No. 73 has been given under test No. 2. notes. October 1. — Fermentation well under way; heavy foam resting on must; no air in the barrel; temperature of the must, 66° F. October 2. — Fermentation progressing rapidl}^ October J. —Fermenting more slowly. Microscopic examination shows yeast to be abundant and a few Apiculatus cells present. October 10. — Condition same as in test No. 6; specific gravity, 1.012. Microscopic examination shows yeast to be abundant, large, and round. No head on liquor; temperature of must, 58° F. October 20. — Liquor very cloudy; slight taste of tannin; aroma very good; specific gravity, 1.0025. October 27. — Partial analysis showed a specific gravity of 1.003; alcohol 4.96 grams and sugar 0.31 gram per 100 cc of cider. October 28. — Racked as in case of No. 6. November 19. — Liquor slightly lighter in color than previous num- bers; slight cloud, not exactl}^ bright; aroma the best of all the tests and flavor very good; specific gravity, 1.001. December 22. — Filled 75 quart bottles. Liquor clear, but not bright; flavor excellent; aroma fruit3^ The remaining cider was left in the barrel tightly bunged. January 5, 190 J^,. — Specific gravity, 0.999. WORK OF 1903-4. ^ 31 January 11. — Analysis of cider remaining in cask gave the follow- ing data: Specific gravity 1. 001 Solids grams per 100 cc. . 1. 76 Sugar do 31 Alcohol .do 5. 60 Acid do 38 January 25. — Bottled the remaining cider in cask. It was filtered through the gravity filter, as in the case of No. 6. The filtered liquor was absolutely clear and bright and of light straw color; aroma good; flavor very good, no aftertaste. April 19. — First bottling: Liquor bright; pale straw color; heavy, dark deposit; strongly gaseous when opened; good bead on glass; bouquet good; flavor rough and strong, scarcely desirable. Second bottling (filtered). Liquor same color as above; slight yeast deposit of light color; slightlj^ gaseous when opened; mild efi'er- vescence in glass; bouquet good; flavor milder; not desirable. May 25. — Second bottling (filtered) : Cider in fine condition; agparP- ently briglit in bottle; a very flocculent but slight amount ofyeast; almost still when opened; very slight amount of gas when poured; bouquet very mild, agreeable; color almost bright, pale amber; flavor very mild — a pleasant, slightly acid, entirel}^ dry, good cider. Anal- ysis of the second bottling at this date gave the following data: Specific gravity 0. 999 Solids grams per 100 cc. . 1 . 69 Total sugar do Trace. Alcohol do .... 6. 36 Acid do 37 Tannin ' do 029 May 25. — First bottling: Far less bright in bottle than filtered sample, with more sediment, not all resting on the bottom; a slight granular flocculent precipitate throughout the entire liquor; slightly gaseous when opened, more so than in filtered sample, though not marked; pours off fairly bright, a pale straw color, decidedly lighter than filtered sample; bouquet faint and pleasant; flavor mild, equal to or a trifle better than filtered sample; decidedly a good cider. No analysis made. June 20. — Samples of this cider, second bottling, filtered, were sent to Dr. H. W. Wiley, Chief of the Bureau of Chemistry, U. S. Depart- ment of Agriculture, and sampled and analyzed with two others, to be described later. He reports on July 18, 1904, that No. 9 " was pro- nounced by a party of three experts to have the finest flavor." This sample analyzed: Sugar, 0.068; alcohol, 6.31; acid, as sulphuric, 0.274 32 CHEMICAL COMPOSITION OF APPLES AND CIDER. (as volatile acid, acetic, 0.037). While this experiment was carried out on the German model, this yeast (No. 73) has again, as in the tests of 1901 conducted on the French plan, given the best product. Cask Experiment No. 10. General notes the same as on cask experiment No. 6. Cask No. 10 was sown on September 30, 1903, with 1 pint of culture of yeast No. 74, prepared as previously noted. The origin of yeast No. 74 is given under test No. 3. NOTES. October 1. — Fermentation started; heavy foam resting on must, but air still in barrel; temperature of must, QQ^ F. October ^. — Fermentation progressing rapidly. October 3. — Fermenting more slowly. October 10. — Condition same as in test No. 6; specific gravity, 1.013. Microscopic examination shows yeast abundant, cells large and round, fermenting quietly. October W. — Liquor very cloudy; tastes of tannin, though very promising; specific gravity, 1.003. October 27. — Partial analysis showed a specific gravity of 1.003; alcohol 5.48 grams and sugar 0.41 gram per 100 cc of cider. October 28. — Racked as in case of test No. 6. November 19. — Liquor a pale straw amber color; fairly clear, but not bright; aroma very good; flavor good; specific gravity, 1.001. December 23. — Bottled 75 quarts unfiltered. Liquor clear, but not bright; aroma very good; flavor not quite so good as test No. 9. Remainder of cider left in barrel tightly closed. January 5, 1904- — Specific gravity, 1.001. January 13. — Analysis at this date of cider left in the cask gave the following results: Specific gravity 1. 001 , Solids grams per 100 cc. 1.91 Sugar do 41 Alcohol do .... 5. 80 Acid do 44 January 26. — Bottled remainder of the cider, filtering as in case of No. 6; condition same as No. 9, except that No. 10 had a sour wine taste. April 19. — First bottling: Liquor bright, pale straw color; heavy, dark deposit; strongly gaseous, good bead; bouquet good; flavor rather rough; not desirable. Second bottling (filtered). Liquor the same; light sediment; not gaseous; bouquet same as above; flavor milder. May 25. — Second bottling: In the bottle resembles No. 9; liquor bright and clear; slight gaseousness when opened, pours very bright; WORK OF 1903-4. 33 bouquet not strong, but pleasant; flavor not very smooth, but good, clear; a fine acid; generally desirable; color, a pale amber shading to straw color. Analysis of this sample on this date gave the following- results: Specific gravity 0. 998 Total solids grams per 100 cc. . 1. 73 Total sugar do Trace. Alcohol do 6. 20 Acid do 37 Tannin do 046 May ^25. — First bottling (unfiltered): In bottle, bright like filtered goods; shows a slight amount of flocculent granules resting in the liquor; practically like filtered product as to gaseousness; color an opalescent, pale amber, shading to straw color. Bouquet weak and a mild, pleasant flavor; apparently the same as the filtered sample. A sample of the second bottling of this cider was sent to Doctor Wile}^, who says, "No. 10 has a good flavor, but not quite so good as No. 9." The analj^sis made at the Bureau of Chemistry, Department of Agri- culture, is as follows: Grams per 100 cc. Sugar 0. 082 Alcohol 6. 12 Acid, as sulphuric 223 Acid volatile, as acetic 037 Cask Experiment No. 11. The general notes are the same as those on cask experiment No. 6. Cask No. 11 was sown with 1 pint of culture of yeast No. 97 on Sep- tember 30, 1903, the bung plugged with cotton, and later fitted with the ventilation apparatus. Yeast No. 97 was isolated at Blacksburg from a small preparation of must of Soulard crab. It has the peculiar char- acteristic of growing in test-tube cultures in colonies or coagulated masses, thus showing at all times a bright liquor. Octoher 1. — Fermenting activel}^; heavy foam on must; air already driven out of cask; temperature of must, ^^'^ F. October 2. — Fermentation progressing rapidl3\ October 3. — Fermenting more slowly. October i6^.— Condition same as in test No. 6; specific gravity, 1.012. Microscopic examination shows 3'east to be abundant; cells large, round. Octoher W. — Same as test No. 6 as to qualitv; sjiecific gravit}', 1.002. October 27. — Partial analysis showed a specific gravity of 1.002; alcohol 5.06 grams and sugar 0.28 gram per 100 cc of cider. October 28. — Racked as in case of test No. 6. 6390— No. 88—04 3 34 CHEMICAL COMPOSITION OF APPLES AND CIDER. Noveniber 19. — Liquor pale straw amber, fairly clear, but not bright; aroma fair; flavor fair; specific gravity, 1.002. Decemher '23. — Filled 75 quart bottles. Liquor clear, but not brigfht; aroma poor; flavor dr}^ and insipid. Remainder of cider left in barrel bunged as usual. January 5, 1901, — Specific gravity , 1.002. January IS. — AnaW sis of stock in barrel gave the following results: Specific gravity 1. 002 Solids grains per 100 cc. . 1. 83 Sugar do 25 Alcohol do 5. 03 Acid do 46 Janyxiry26. — Bottled remainder of cider, filtering as in case of No. 6. Liquor clear, bright amber; aroma a little unpleasant; flavor poor, dry, and insipid; not good. Ajyril 19. — First bottling: Liquor ver}^ bright indeed; sediment abundant, flocculent, rather light in color; very gaseous, pours with good bead; bouquet mild; flavor pleasant. This sample has greatly improved. Second bottling (filtered): Sediment abundant; bright color same as in first bottling; gaseous; bouquet mild and good; flavor milder than at the first bottling; desirable; decided improvement since bottling. May 9. — Second bottling: Color a light amber; odor pleasant; nearly dr}^ flavor slightly milder than No. 6. 2£ay 25. — First bottling (unfiltered): Not bright in bottle; slight yeast present; liquor opalescent; flavor slightly acid, but not unpleas- ant, dry; qualit}^ medium. May 25. — Second bottling (filtered): In bottle its general appear- ance is opalescent, not bright and limpid; a heavy, dark sediment in bottom; strongly gaseous, pours fairh^ bright, with beautiful spark- ling foam; bouquet pleasant, stronger than unfiltered sample; flavor a trifle rough, lacks clearness; sound and dr}^, quality medium. Analysis of filtered sample on this date gave the following results: Specific gravity 0.999 Solids grams per 100 cc. 1. 76 Total sugar do Trace. Alcohol do 5.19 Acid do 34 Tannin do 051 SECOND SERIES OF EXPERIMENTS, CASKS NOS. 12 TO 16. A second set of casks were filled and sown with yeast cultures on October 7, 1903, as a partial duplication of the first series, Nos. 6 to 11. In this series some other yeasts were introduced and the must used WORK OF 1903-4. 35 had a slightly different composition. It was intended to bottle this set with a larger sugar content and thus vary the detail somewhat. Four casks were sown, viz, Nos. 12 to 15 with yeasts as specified under each number. On October T, 1903, cull apples of a common stock were ground and a sample of the must sent to the chemist for analysis, which gave the following results: Specific gravity 1. 053 Solids grams per 100 cc. . 13. 66 Total sugar do 11 . 66 Reducing sugar do 7. 87 Sucrose do: . . . 2. 97 Acid do 44 Tannin do 059 All the casks were cleansed and handled the same as Nos. 6 to 11, and were placed beside these former numbers; hence the general notes and cellar temperatures given for No. 6 after October T apply to this series of experiments also. Cask Experiment No. 12. Cask No. 12 was sown October 7, 1903, with 1 pint of pure culture of yeast No. 8. The origin of this yeast has been previously given under cask No. 6. NOTES. October 9. — Fermenting with vigor. October 10. — Fermenting more rapidly. October W. — Fermentation slowing down; no head on liquor; tem- perature of the must, 53^ F^ ; cellar temperature, 52^ F. ; a decidedly characteristic taste, very good, clearer than any of the first lot; spe- cific gravity, 1.019. October ^5. — Cellar temperature, -IS^ F.; temperature of must, 49° F.; condition of cider, very good; opalescent amber, brightest in color of any number in the test. October 27, — Partial analysis gave a specific gravity of 1.012; alco- hol 3.77 and sugar 2.40 grams per 100 cc of cider. October 28. — Racked as in case of test No. 6. November 19. — Cider very dark amber; clear, but not bright; aroma very good; flavor excellent; specific gravity, 1.010. January 23, 190 Jf.. — Specific gravity, 1.011. January 26. — Analysis of this date gave the following figures: Specific gravity 1. Oil Solids grams per 100 cc. . 3. 84 Sugar do..-- 2.11 Alcohol do-.-- 4.23 Acid do 54 Tannin do 034 36 CHEMICAL COMPOSITION OF APPLES AND CIDEK. This liquor was filtered through the gravity filter and 100 quarts were bottled. It was of a clear, bright, amber color; aroma very good; flavor excellent. This sample was lost and no further notes could be made. The sugar content of 2.11 gave it a character much more agreeable to the taste of most Americans than that of dry ciders. Cask Experiment Xo, 13. This barrel was filled and sowed October T, 1903, with yeast No. 66, in the manner previously described. The origin of this yeast is given under Ko. 8. NOTES. October 9. — Fermenting very rapidly. October to. — Fermenting rapidly. October 20. — Condition same as in test No. 12, except that liquor is not quite so clear; specific gravity, 1.018; character that of ordinary fermenting cider. October 25. — Temperature of must, 49^ F.; liquor cloud}^; specific gravity, 1.012. October 27. — Partial anal3^sis of tnis date gave a specific gravity of 1.010; alcohol 1.29 and sugar 1.72 grams per 100 cc of cider. JVovember 2. — Kacked into a fresh barrel, previously well sulphured and rinsed with hot water. November 19. — Cider a ver}^ dark amber; clear, but not bright; aroma good; flavor very good. January 23, 190 J^. — Specific gravity, 1.006. Jamiary 26. — Analysis on this date gave the following results: Specific gravity 1. 007 Solids grams per 100 cc. . . 3. 06 Sugar do.... 1.08 Alcohol do 4. 54 Acid do 42 Tannin do 042 January 27. — Filtered and bottled 25 quarts in apollinaris bottles and 50 quarts in common bottles. The cider is pale amber; clear, but not bright; aroma good; flavor good; a slight tannin taste; no aftertaste. April 19. — Cider very bright, pale straw color, best in this series; slight flocculent 3east, very gaseous, foamed over when cork was drawn; bouquet best of all in test; flavor excellent; cider not yet mature. May 9. — Color light amber, perfectly clear and bright; odor very pleasant, drj^, aromatic; peculiar aromatic flavor very marked as compared with others. WORK OF 1903-4. 37 May 25. — Bright, beautiful amber color; decidedly gaseous; pours with beautiful bead, clear, pale amber; decidedly fruit}^ bouquet; flavor slightly acid. Anal3'sis on this date resulted as follows: Specific gravity 1. 001 Solids grams per 100 cc. . 1. 83 Total sugar do 35 Alcohol do 5. 16 Acid do 35 Tannin do 042 This yeast produced in this case a fine grade of effervescing cider, equal to the best French mousseux ciders. While the general char- acter of this cider is the same as that from yeast No. 73, cask 15, there is still a decided difference, which can not be readily defined in words. This difference would appear to be due to the character of the yeast used. Cask Experiment Xo. 14. Cask No. 14 is omitted from this report because the results are not of sufficient interest to warrant presentation. It was sown with yeast No. 71, a form isolated from wine lees secured by Mr. Alwood from Alsace, Germany. This j^east is a peculiar form, always growing in coagulated masses and leaving a very clear, bright liquor in the fer- mentation flasks, but in barrel tests-it has in no case shown any valu- able characteristics. Cask Experiment No. 15. General notes the same as for test No. 12. Cask No. 15 was filled and sown on October 7, 1903, with 1 pint of culture of yeast No. 73. The origin of this yeast has been previously given under No. 2. notes. October 9. — Fermenting slowly. October 10. — Fermenting more rapidly. October 20. — Fermenting moderately; temperature of must, 53.5° F. Character that of ordinary fermenting cider; specific gravity', 1.024. October 25. — Temperature of must, 49. o'^ F. ; cider, cloudy; flavor good; specific gravity, 1.014. October 27. — Partial analysis on this date shows a specific gravity of 1.013; alcohol 3.85 and sugar 2.42 grams per 100 cc of cider. November 2. — Racked as in case of test No. 13. November 19. — Liquor dark amber, cloud}'; aroma very good; flavor very good; specific gravity, 1.008. January 23, 1901/,. — Specific gravity, 1.005. 38 CHEMICAL COMPOSITION OF APPLES AND CIDER. January 27. — Analysis as follows: Specific gravity 1. 004 Solids grams per 100 cc. . 2. 36 Sugar do 78 Alcohol do 4. 80 Acid - do 34 Tannin do. . . . .039 January 29. — The cider was filtered through a gravity filter and 100 quarts put up in apollinaris bottles. It is clear, not quite bright; aroma excellent; slight flavor of tannin; no aftertaste; very good quality. April 19. — Liquor very clear, color pale; yeast sediment light, floc- culent; fairly gaseous when uncorked; good foam when poured; beautiful in glass; bouquet excellent; a promising cider. May 9. — A fine, deep amber color; almost perfectly bright; odor very pleasant, very fragrant; bouquet of the best — fine, dry, and mild; fine flavor. May 25. — Decidedly gaseous, sparkling; bright, clear amber, lighter than usual with this yeast; bouquet strong, pleasant, fruit}^; flavor mild, pleasant, agreeable; quality good; entire absence of rank, harsh taste; no after taste. Analysis on this date as follows: Specific gravity •. 1. 001 Solids grams per 100 cc. 1.98 Total sugar do 35 Alcohol do- - . . 5. 37 Acid do 39 Tannin do 046 A sample sent to Washington in June was sampled by three experts and described as follows: ''^o. 15 is a sparkling cider, which property to a certain extent interferes with the delicacy of the determination, but it is pronounced also to be of excellent flav^or." The analysis made in the Bureau of Chemistry gave a sugar content of 0.112; alcohol, 1.95; acid, as sulphuric, 0.216; and volatile acid (acetic), 0.059 — as expressed in grams per 100 cc. SPECIFIC GRAVITY AND CONTROL OF FERMENTATION. The question of proper control of fermentation is one of very great importance, and the operator should be able to gauge at all times the rapidit}^ with which the sugar is being consumed. This can be determined with more or less accuracy by the hydrometer readings, which indicate the specific gravit}^ or density of the must or ferment- SPECIFIC GRAVITY AND FERMENTATION. 89 ing liquor. However, these readings can not be implicith' relied upon because of the variable quantit}^ of nonfermentable solids. No one has 3^et been able to devise a method by which gravity determinations can be made to indicate composition with chemical accuracv, but the table published on page 89 of Bulletin 71, Bureau of Chemistr}^, seems to come within such reasonable bounds of accuracy that it may be used as a guide in the fermentation room. With a view to illustrating the use of this cellar table all the hydrometer readings taken during fermentation of the ciders made at this station, the chemical anah^ses made at the several stages of fermen- tation, and the approximate percentages of sugar and alcohol deter- mined theoretically, have been arranged in parallel columns in Table YII. In those instances where only a hydrometer reading is given there is of course no comparison, but where alcohol and sugar deter- minations were made the comparison is direct and interesting. In a considerable number of instances. the calculated or approximate per- centages are close indeed to those actuall}^ determined b}^ analj'sis, but in several instances they are wide apart. The peculiarities of yeast races has to do with this matter, as we have definite!}^ proved that cer- tain 5^easts are able to produce a higher percentage of alcohol in identical musts than others. Also, when the theoretical table was com- piled it was assumed that the nonsugar solids always exceeded 2 per cent in normal must and ciders, but this does not appear to be alwa} s true, as shown by the anah^ses of the special ciders made with pure yeasts at this station. Table YII. — ^-1 comparison of gravity determinations and analyses made at various stages of fermentation, with the percentages of sugar and alcohol calculated from gravity read- ings alone. « WORK OF 1901-2. Date. Sample. Specific gravity. Grams per 100 cc as determined by analysis. Approximate percentages as calculated. Total solids. Sugar- free solids. Total sugar. Alco- hol. Total sugar. Alco- hol. September 24 Original must . . Test No. 2 do 1.050 1.026 1.006 1.007 1.004 1.020 1.003 1.003 1.003 10.15 0.00 October 4 6.80 1.98 4.82 1.16 1.02 .98 4.16 .27 2.76 4.68 4.44 4.43 3.21 5.36 5.35 1.35 1.55 .95 4.15 2.40 November 23 4.40 January 20 .do . . .. 2.87 2.60 5.72 1.85 1.62 1.56 4.30 Mavl6 do 4.60 October 4 Test No. 3 do. .. 3.00 November 23 . 75 4. 70 Januarv 20 May22'. do do 2.33 2.24 2.03 2.04 .30 .20 5.09 5.20 .75 .75 4.70 4.70 For table of hydrometer readings, see page 89, Bui. No. 71, Bur. of Chem., U. S. Dept. of Agr. 40 CHEMICAL COMPOSITION OF APPLES AND CIDER. Table VII. — A comparison of gravity determinations and ana of fermentation, etc. — Continued. FIRST SERIES OF EXPERIMENTS, 1903-1. made at various stages Date. Sample. Specific gravity. Grams per 100 cc as determined by analysis. Approximate percentages as calculated. Total solids. Sugar- free solids. Total sugar. Alco- hol. Total sugar. Alco- hol. September 30 Original must . . Test No. 6 .. do 1.051 1. 012 1.004 1.002 1.002 1.003 .999 1.019 13.04 2.96 10.08 0.00 10.38 2.58 .98 .58 .58 .78 .00 3.98 1.38 .98 1.19 .98 3.^8 0.00 October 10 1 3.90 October 27 .46 4.76 4.70 November 19 do 4 90 January 5 .. do :... 4.90 do 1.97 1.79 1.'55 1.75 .38 Trace. 5.35 5.66 4.80 May25'. October 10 do Test No 7 5.19 3.2> October 27 do 1.006 1.004 1.005 1.004 1.019 1.005 1.004 1.002 1.003 1.012 .96 4.61 4 53 November 19 do 4.70 January 23 do 4.60 Januarv 25 do 2.48 1.84 .64 5.28 4.70 October 10 Test No. 8 do 3. -20 October 27 1.28 5.24 1.18 ' 4 6!> do .98 .58 .78 2.58 .78 ..38 .00 .38 .00 2.78 .78 .78 .38 .38 .38 .00 2.58 .58 4.70 January 23 . . do 4 93 do 2.64 1.74 .90 6.00 4 8> October 10 Test No. 9 3 93 October 27 do 1.003 1.001 .999 1.001 .999 1.013 1.003 1.003 1.001 1.001 1.001 .998 1.012 1.002 1.002 1.002 1.002 1.002 .999 .31 4.96 4 8) November 19. do . 5 0) do 5.13 January 11 do _. . 1.76 1.69 1.45 1.69 .31 Trace. 6.60 6.36 5 0) May25 October 10 do Test No. 10 do 5 1) 3.8) October 20 4.8) October 27 do .41 5.48 4.83 November 19 do 5.0* do 5.03 January 13 do 1.91 1.73 1.50 1.73 .41 Trace. 5.80 6.20 5.00 May 25 do 5.19 October 10 TestNo.ll do 3.90 October 20 4.'0 October 27 do .28 5.06 .58 4.90 November 19 do .58 4.90 January 5 do .58 .58 .00 4.90 January 13 do 1.83 1.76 1.58 1.76 .25 Trace. 5.03 5.19 4.90 May25 do 5.19 SECOND SERIES OF EXPERIMENTS, 1903-4. October 7 Original must . . October 20 Test No. 12. October 27 do November 19 do January 23 do January 26 do October 20 i Test No. 13. October 25 do October 27 do January 23 do January 26 | do May 25 1 do October 20 1 Test No. 15. October 25 do October 27 do November 19 do January 23 do January 27 do May 25 do 1.053 1.019 1.012 1.010 1.011 1.011 1.018 1.012 1.010 1.006 1.007 1.001 1.024 1.014 1.013 1.008 1.005 1.004 1.001 13.66 2.00 11.66 0.00 10.84 4.04 2.64 2.24 2.44 2.44 3.84 2.64 2.24 J. 44 1.64 .44 5.04 3.04 2.84 1.84 1.24 1.04 .44 2.40 3.77 3.84 1.73 2.11 4.23 1.72 4.29 3.06 1.83 1.98 1.48 1.08 .35 4.54 5.16 2.42 3.85 2.36 1.98 1.58 1.63 .78 .35 4.80 5.37 COMPARISON OF ANALYSES. 41 COMPARISON OF ANALYTICAL DATA. The final analyses of the finished ciders made in our experiments are broiig-ht together in Table VIII. An inspection of these data shows the remarkably uniform character of the ciders in regard to specific gravity, acid, and sugar-free solids. The three samples of must from which these various ciders were made were so nearly alike that no deduction can be made on this point; yet in alcohol content there is a striking variation throughout, and even in samples from the same must where the sugar is practically^ exhausted, as in tests Nos. 9 and 11, there is a whole per cent difference in alcohol content. This affects greatly the character of the beverage, and in other characteristics, as effervescence, aroma, and flavor, these ciders were very different. The indications are that there is here a fruitful field for further investigation. The sugar content in all these ciders was low, and in several prac- tically exhausted. No sucrose whatever was present, and in fact there never is any sucrose remaining in a properly fermented cider, as this form of sugar is promptly inverted during the first fermenta- tion. Table VIII contrasts strangely with Tables IX and X, in which are presented the analyses of miscellaneous ciders collected for study and comparison. Table VIII. — Final analyses of tlie finished ciders made ivithpure yeast cultures at the Virginia station, 1901-4. Test No. Yeast No. Specific gravity. Grams per 100 cc. Sample No. Alco- hol. Acid as sul- phuric. Total sugar. Total solids. Sugar- free solids. Remarks. 137 2 73 1.004 4.43 0.35 0.98 2.60 1.62 Made from the same must, sp. gr. 1.050. 138 3 74 1.003 5.20 .48 .20 2.24 2.04 304 6 8 .999 5.66 ,33 Trace. 1.79 1.79 305 7 37 1.004 5.28 .43 .64 2.48 1.84 306 ' 8 66 1.003 6.00 .39 .90 2.64 1.74 Made from the same 307 9 73 .999 6.36 .37 Trace. 1.69 1.69 must, sp. gr. 1.051. 308 10 74 .998 6.20 .37 Trace. 1.73 1.73 309 11 97 1.003 5.37 .34 Trace. 1.76 1.76 310 12 8 1.011 4.23 .54 2.11 3.84 1.73 311 13 66 1.001 5.16 .35 .35 1.83 1.48 312 313 14 15 71 73 1.005 1.001 4.76 5.37 .32 .39 .75 .35 2.39 1.98 1.64 1.63 Made from the same must, sp. gr. 1.053. 314 16 97 1.000 5.00 .35 Trace. 1.59 1.59 315 21 37 1.003 4.66 .41 .38 2.17 1.79 316 18 74 1.001 5.09 .40 .27 1.93 1.66 330 17 erage . . Wild. 1.005 5.48 .38 1.41 2.73 1.32 Av 1.002 5.26 .39 ! .52 2.21 1.69 Tables IX and X present the results of analyses of American-made ciders collected for comparison during this investigation, and analyzed at the Bureau of Chemistry and at the chemical laboratory of the Vir- ginia Agricultural Experiment Station. Among these samples there are some of fine quality, as determined both by anah^sis and sampling. Those given in Table IX are among the best, but others of the com- paratively dry ciders are commendable. 42 CHEMICAL COMPOSITION OF APPLES AND CIDER. The important point in these tables is the great variation in compo- sition of the beverages sold as cider. How shall we determine what a cider is until we have some definite idea as to how this beverage shall be fermented and handled so as to preserve its valuable properties l The fluctuations in sugar content from nothing to 13.56 per cent, and in alcohol content from nothing to 6.87 per cent, give the full range of variation from fresh apple juice to a completed cider. Between these extremes various compositions are sold as ciders. The samples showing such high sugar content are ordinarih' treated with pre- servatives or sterilized by heat, as it is difficult to bottle and hold a liquid containing much above 1.5 or 2 per cent of sugar. Table IX. — Analyses of commercial samples of American-made ciders {Bureau of Chemistry, U. S. Dej^artment of Agriculture, 1901). Name or brand. Specific gravity. Grams per 100 cc. Sample No. A1C.V Total \±-|"i^;Jr- hoi. acids. j.;!f, ,^|, Total . , solids. ^^^'• 50 51 52 53*« 53 Sparkling draft cider, extra dry. Sparkling draft cider . 1.0053 1.0101 .9987 1.G178 1.0289 1.0292 4.66 0.2979 0.0890 4.42 ! .3508 .1340 6.22 1 .3626 .0860 4.37 ; .-^372 .0490 1.71 .4567 i .0250 3.12 .0220 1.15 2.11 .00 3.34 5.99 5.17 3.39 0.2830 4 67 1 2880 2.86 i .2920 Crab-apple cider 6.70 1 2770 Paulding Pippin cider, 1900 Same 1899 8.23 .2410 9.03 .2830 Table X. — Analyses of commercial samples of American-made ciders ( Virginia Agri- cultural Experiment Station, 1901-4). Name. t bo Grams per 100 cc. o a> -i li-i i r^x Preservatives. 1 1 < > 1^ -§5 m 32 11 139 Refined cider 1.025 2.69 0.57 0.038 4.54 4.54 0.00 7.27 2.73 Not tested. 140 Dry still cider 1.000 6.35 .28 .060 .08 .08 .00 2.45 2.37 Benzoic acid and saccharin. Do. 141 do 1.000 6.27 .29 .076 .08 .08 .00 2.49 2.41 142 .....do 1.000 6.87 .31 .080 .00 .00 .00 2.17 2.17 Do. 143 Country cider 1.065 .35 .66 .021 13.52 '12.73 .75 16.86 3.30 Benzoic acid. 144 , Labeled cham- 1.052 .00 .37 9.16 j 8.50 •62 12.63 3.47 Not tested. pagne cider. I 1 145 1 Gilson's cider 1.040 .95 .42 8.86 ! 7.29 1.49 1 9.84 .98 Do. 146 ! Paulding's pippin. 1.046 .87 .48 9.02 : 8.12 .86 11.55 2.53 No preservatives. i 1901. 1 317 j "Extra Dry" 1.013 4.56 .57 2.14 2.14 .00 ! 4.41 2.27 Do. 318 ; Standard dry re- 1.027 2.81 .43 ' 5.12 5.12 .00 ! 7.29 2.17 Do. fined. 1 1 ^^\ Mott'ssauterne... 1.012 4.40 .52 1.40 1.40 .00 4.05 2.65 Do. 332 1.004 1.010 4.36 4.07 .34 .53 .26 .38 .26 .38 .00 .00 2.58 4.20 2.32 3.82 Salicylic acid. 333 Cider, 1903 Do. 340 Cider B 1.026 1.005 1.032 1.033 2.45 4.71 3.40 3.62 ..50 .28 .45 .63 5.93 1.19 7.36 7.20 5.93 1.19 6.97 6.42 .00 .00 .37 .74 8.11 3.04 9.85 9.89 2.18 1.85 2.49 2.69 No preservatives. 341 cc 34'> R. 1 Do. 343 Golden russet Do. 344 Duffy's unfer- mented cider. 1.056 .09 .59 11.37 11.08 .24 15.27 3.90 Do. DESCRIPTION OF SAMPLES. 48 NOTES ON SAMPLES OF CIDERS FROM TABLES VIII, IX, AND X. Sam/pie 137. — A cider made with a pure j^east culture isolated at the Virginia Agricultural Experiment Station and known as Sauterne or No. 73. The cider was, when finished, a dry, etfervescing or sparkling cider. It is discussed under test No. 2, 1901. The same yeast was used in tests Nos. 9 and 15, 1903. Sample 138. — A cider made with a pure 3^east culture isolated at the Virginia Agricultural Experiment Station and known as Vallee d'Auge or No. Y4. This was a very dry cider. It is discussed under test No. 3, 1901. The same yeast was used in test No. 10, 1903. Sample 30 J^.. — A cider made with a pure yeast culture isolated by Mr. Alwood at the Royal Pomological School, Geisenheim, German}^, and known as St. Ouen-de-Thouberville or No. 8. It is discussed under test No. 6. The same 3^east was also used in test No. 12. Sample 305. — A cider made with a pure j^east culture isolated as the above and known as yeast No. 37. It is discussed under test No. 7. Sample 306. — A cider made with a pure 3^east culture isolated at the Virginia Agricultural Experiment Station and known as yeast No. 66. It is discussed under test No. 8. The same yeast was used in test No. 13. , Sample- 307. — A cider made with the same yeast, No. 73, as was used in sample 137. It is discussed under test No. 9. The same yeast was used in tests Nos. 2 and 15. Sample J6^5.— Made with the same yeast. No. 71, as that used in sample 138. It is discussed under test No. 3. The same yeast was used in test No. 10. Sample 309. — A cider made with a pure yeast culture isolated at the Virginia Agricultural Experiment Station from Soulard Crab and known as yeast No. 97. This cider is discussed under test No. 11. Sample 310. — Made with the same yeast. No. 8, as was used in sam- ple 304. Discussed under test No. 12. Sample 311. — Made with yeast No. 66, the same as that used in sam- ple 306. It is discussed under test No. 13. Sample 312. — This cider was made with veast No. 71, isolated at the Virginia Agricultural Experiment Station from wine lees brought from Alsace, Germany, by Mr. Alwood. The result of the fermen- tation was not such as to warrant special discussion. It is mentioned under test No. 14. Sample 313. — This cider was made with veast No. 73, used in sam- ples 137 and 307. It is discussed under test No. 15. Sample 311^,. — This cider was made with yeast No. 97, used also in sample 309. It is not given special discussion, because the results do not warrant particular mention. 44 CHEMICAL COMPOSITIOISr OF APPLES AND CIDER. Bairiples 315^ 316, and 330. — Not discussed for like reasons. Sample Jf9. — A comparatively dry cider, made in a large factor}^ with ordinar}^ or wild yeast fermentation; slightly gaseous from flask fermentation. Sample 50. — A cider from the same source, not fermented so dry. and charged by natural yeast fermentation. Sample 51. — A cider from the same source, fermented perfectly dry, uncharged. Sample 52. — A special brand of cider made from selected crab apples and only partially fermented before bottling; heavily charged by natural fermentation. Sa7)vple 53a. — A special cider made from selected pippins in 1900, onl}^ partially fermented, and bottled while sweet; heavily charged by natural fermentation. Sample 53. — The same brand of cider from the same factory, made in 1899. It shows greater alcoholic strength and was more heavily charged by natural fermentation. (The last three samples were bottled in heav}^ champagne bottles and foamed over on drawing the cork. All were extra line ciders.) Sample 139. — A refined cider made in Vermont. The stock was on o year old and only partially fermented. Sample llfi. — A dry, still cider from New York. This was a cider made from must sown with a pure yeast furnished by the Virginia station. Sample 11^1. — A cider like sample 140, made in a like manner and by the same parties. Sample 11^. — From the same cellars as samples 140 and 141; a simi- lar cider made with natural 5^easts. Sample 11^3. — A country-made cider, or so called. The analysis showed that it was not a cider, as only slight fermentation had taken place. The liquor was very turbid and muddy looking, and was heavily treated with benzoic acid to prevent fermentation. This sample was quite unfit for use, though it was not worse than many ciders com- monly sold. Sample IJt-Jf.. — Labeled ' ' Champagne cider.-' This was also a country cider of somewhat better character so far as the appearance of the juice was concerned, but quite unfermented. From the examination it appeared that the apple juice had been filtered, heated so as to destroy the organisms present, and bottled. Such a preparation is not a cider. Sample IJfJj. — A country cider shipped in small kegs to the city for hotel use. The analysis shows that this cider also was onh^ slightly fermented, and the liquor was in a mudd}^, uninviting condition. Like No. 243 it was scarcely fit for use. DESCRIPTION OF SAMPLES. 45 Sample lJf6. — This was a sample of bottled cider in fine condition in so far as the condition of the juice was concerned, but it had been bottled almost without fermentation, and unless sterilized or stored in a very cold place the bottles w^ould sureh' have burst in time. It is not possible to carry in bottles 9 per cent of total suo^ar without ster- ilizing, placing- in cold storage, or using preservatives. Sample 3 17. — Labeled '' Extra dry refined cider." Chemical analysis shows that it contained over 2 per cent of sugar, so that it certainly could not be called a dry cider, and unless sterilized or processed even this quantity of sugar is liable to burst any but the best bottles. Sample 318. — Labeled ''Standard dr\^ refined cider." This sample shows by analysis over 5 per cent of sugar; hence it is in no sense a dry cider, and could not well be held in ordinar}^ bottles without ster- ilization or the use of preservatives. Sample 331. — This cider was made b}^ the same persons who fur- nished the two previous samples, from Sauterne yeast obtained from the Virginia station. It has very much the character of the cider made from Sauterne yeast at the station, and far excelled samples 317 and 318. The analysis shows 1.40 per cent of sugar, a desirable amount for ordinary use. Sample 332. — Labeled '' Dry cider," and the analj^sis shows that practically all the sugar had been consumed. Sample 333. — A cider resembling sample 332, and made bj^the same person. Sample 3Jt.O. — An ordinary refined cider made by a large manufac- turer. This cider was fermented partialh , then refined b}" filtering through paper pulp. While this produced a fine, clear liquid, it did not remove all the yeasts, and this cider when bottled became very gaseous. Though put up in champagne bottles, there was danger of bursting them if kept long in a warm room. The percentage of sugar was entirely too high for bottled goods. The character of the cider was fair; it was deficient in flavor and bouquet. Sample 31^1. — Made from ordinary apples b}^ the same manufacturers as sample 340 and fermented to 0° on the Black cider spindle, then refined with wine finings and bottled. Though it showed the same per cent of sugar as the previous sample, this cider was perfectlv still when opened. It had a bright and fine color, but in bouquet and flavor left much to be desired; in fact, it was scarcely palatable. Sample 3Ii2. — A cider made by the same manufacturers as samples 340 and 341, from a fine grade of apples, partialh^ fermented, refined through paper pulp, and bottled. The chemical analysis showed 7 per cent of sugar in this sample, and yet it was perfect!}^ still when opened and no fermentation could be detected. The flavor of this cider was very objectionable, almost unpalatable. How it was preserved with- 46 CHEMICAL COMPOSITIOT^ OF APPLES AND CIDER. out further fermentation in bottles is not understood, as the ordinary preserv^atives could not be detected. Sample SJ^S. — A so-called champagne cider made from fine apples and fermented down to 14° on the Black cider spindle; then clarilied, bottled, and charged artificiall}^ with gas. This was a very beautifi:' bright cider, sparkling like champagne when opened, and made a '^ appearance in the glass. It was not of very good quality, but ' greatly improved b}^ the presence of the gas. This cider showed o\ . r T per cent of sugar, yet after uncorking it stood for a month in the laboratory without showing the slightest fermentation. Notwith- standing this, none of the ordinary preservatives could be detected in it. Sown with a fresh yeast culture it fermented slowly. Sample SJfJf. — A beautiful, clarified sample of apple juice,' unfer- mented. This juice had been refined in a most skillful manner, bot- tled, and charged artificially with gas. Apparently no fermentation had taken place in it and the juii^^^^ fresh as when put up. 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