Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. TEMPERATURE, MOISTURE, AND RELATIVE HUMIDITY OF STORED TOBACCO X ehh THRE as pert. IN eee , | t al Lis \ ATIONAL hs ant JUL 46 19/0 rennts QUaREtl eEnihh bees Agricultural Research Service UNITED STATES DEPARTMENT OF AGRICULTURE ARS 51-32 June 1970 ACKNOWLEDGMENTS Cooperators who furnished facilities and services for this experiment were the James I, Miller Company and the Flue-Cured Tobacco Cooperative Stabilization Corporation, CONTENTS Page| AcknOowledsments 1.25.6 ww ares ce a eicawiee cece 2 SUIMIMATY 2.4u ote. ere 6 aretcve eieca! ate w 1scelnloielcie s) 06's ere cyerers 3 INCPOMUCEION \. s:saeie s rs eieioiew s15.se eles clereisiel a elses ona PYOCEdUTES: 5s cie:6 sieleie cistetwin Soe ores oie beieia eteisiersiee | UD Results e@eoo0ee200820@e@ee80ePeP@K9FHKTFK9 FP H8TFT8FH88T FEE Se 6 TEMPERATURE, MOISTURE, AND RELATIVE HUMIDITY OF STORED TOBACCO ° Danie Childey | EwOverby.) and Bog. Watkins” SUMMARY Flue-cured tobacco is aged for a minimum of 2 or 3 years. During this period, the tobacco mellows, develops a characteristic aroma and color, and improves in burning quality. Despite the many years that have passed since producers first began aging tobacco, the amount of published data on the temperature and moisture of the commodity during storage is meager. While in storage, tobacco is subject to attack by insects. To better understand the ecology of insects that attack tobacco, we obtained data on out- side and warehouse temperatures and relative humidities, and on the effects of these factors on temperature and moisture of tobacco in storage. These data were obtained during 1967 from a tobacco warehouse in Wilson, N. C. INTRODUCTION Tobacco is normally aged for a few years before it is considered ready for use. The length of the aging or storage period depends on the type of tobacco, and the demand for raw tobacco. While in storage, tobacco is exposed to possible invasion and damage by insects. One of the types of tobacco aged for 2 to 3 years or often longer is flue-cured. In the United States it is stored primarily in the Middle Atlantic States. The tobacco is usually prized in wooden hogsheads 4 feet long and 4 feet in diameter to a net weight of approximately 950 pounds. The hogsheads are stored in unheated warehouses, One of the most common structures used for tobacco storage consists of a composition flat roof, concrete floor, and sheet-metal sidewalls. Side and roof vents are the main source of ventilation. Although the tobacco industry considers the storage period essential for fermen- tation of raw tobacco, temperature and moisture conditions during this period are 1/ — Entomologist, biological laboratory technician, and former biological laboratory technician, respectively, Stored-Tobacco Insects Investigations Laboratory, Richmond, Va., Market Quality Research Division, Agricultural Research Service, U.S. Depart- ment of Agriculture. practically unknown, or at least have not been published. Dixon, Darkis, Wolf, and others=’ reported on the natural aging of flue-cured tobacco, but they used open- louvered storage in their experiment -- a type that is no longer the universal standard, Laboratory and field experiments by Runner?’ and Swingle2/ indicated that low temperature may control the cigarette beetle, a prime pest of stored tobacco. Howe lists the cigarette beetle as moderately cold hardy, needing a relative humidity of about 30 percent for survival. Solomon—’ believes that insect density-dependent regulation must occur in all populations that persist for any considerable number of generations. He states that weather factors themselves generally are not responsible for population density and they cannot exercise such regulation alone, but only in conjunction with density-dependent processes. He thinks that insect infestations that persist manage temperature and moisture conditions favorable to the organism, Armstrong—’ and others follow this theory, indicating that insects in grain may multiply sufficiently to heat the mass, thereby retarding or preventing cooling by natural convection currents and conduction. Flue-cured tobacco enters storage practically void of living insects. Most ecolo- gists agree that temperature affects the insect more when the population density and moisture level are low and microenvironment inhabitants are ata minimum. These conditions prevail when flue-cured tobacco first enters storage. Data are needed on the effects of outside temperature and relative humidity on conditions inside the tobacco warehouse during storage, and on the effects of these conditions on the temperature and moisture of the tobacco in the hogsheads. These conditions were monitored during 1967 at a warehouse in Wilson, N. C. 2/Dixon, L. F., Darkis, F. R., Wolf, F. A., and others. Natural aging of flue- cured cigarette tobaccos. Indus. Engin. Chem. 28(2): 180-9. 1936. 3/Runner, G. A. The tobacco beetle: an important pest in tobacco products, U.S. Dept. "Aer. Bula (3itwil pp.e1919. 4/swingle, M. C. Low temperature as a possible means of controlling the cigarette beetle in stored tobacco. U.S. Dept. Agr. Cir. 462, 8 pp. 1938. 5/Howe, R. W. A summary of estimates of optimal and minimal conditions for population increase of some stored-products insects. J. Stored Prod. Res. 1(2): 177-84, 1965, 6/Solomon, M. E. Status of the idea that weather can control insect populations. XI Internatl. Cong. Ent. Bul. Proc. Vol. 2, sect. 7, pp. 126-30. 1962. a Armstrong, M. T. Preventing infestations of farm stored grain without using chemicals, XII Internatl. Cong. Ent. Bul. Proc. Vol. 1, sect. 9B, p. 628. 1965, PROCEDURES The tobacco warehouse (fig. 1) used in this study was approximately 180 feet long, 130 feet wide, and 20 feet high. The side walls were constructed of sheet metal; the roof was sheet metal with outside surface coated with tar; and the floor was concrete. Five roof vents were located along the peak of the shallow A-frame roof. Vents along the sides of the building were closed throughout the year. Ventilation in the building was restricted primarily to leakage around the side vents and aisle doors, and air moved from these points toward the roof vents. Throughout the year, the warehouse held nearly its full capacity of 3,696 hogsheads. The hygrothermographs used to monitor outside and warehouse temperature and relative humidity were equipped with 7-day clocks and hair sensors for humidity detec- tion. An official U. S. Weather Bureau Station was used to house the outside instrument. The station was located approximately 30 feet from a side of the warehouse. A central aisle 12 feet wide separated the warehouse into two equal sections. Space near the center of one section was alloted tor a monitoring station. At this station, warehouse temperature and relative humidity were monitored at elevations of 2, 8, and 16 feet above floor level. From a row of hogsheads nested four tiers high near the station, a hogshead from each tier along a diagonal line was selected for monitoring Figure 1.--Tobacco warehouse used in climatic study. 5 tobacco temperature and moisture. The top of the hogshead on the upper tier coincided with the 16-foot elevation used to monitor conditions inside the warehouse. The hogs- heads monitored were prized in October with 1966-crop tobacco, type 11-A, grade B4F. In each of the four selected hogsheads, tobacco temperature was monitored at 4-, 12-, and 20-inch depths. Copper-constantan thermocouples were used to detect temper- ature, and readout was made with a 24-point transistorized recorder. The recorder was automatically activated daily at noon for about 6 minutes. Measurements were accurate to within +0.5°F. Tobacco moisture was monitored with dial-stem hygrometers having animal mem- brane as the moisture detector. Moisture was monitored in each of the four hogsheads at depths of 4 and 12 inches. The hygrometers remained in the tobacco continuously, but readings were made only weekly. Moisture accuracy was within +0.5 percent calcu- lated on a wet basis. All instruments were checked for calibration at 4-week intervals. At each cali- bration, the hygrometers were rejuvenated with moisture. The field instruments were calibrated to an electric hygrometer indicator using sensors of bifilar windings of palladium hygroscopically coated with lithium chloride. RESULTS The data have been condensed into tabular and graphic form for presentation. De- tailed data are available for inspection at the Tobacco Insects Investigations Laboratory, Richmond, Va. Figures 2-4 show the outside temperature range and the related mean warehouse temperature data. During the year, the mean warehouse temperature in a reduced fluctuating pattern followed closely the higher temperatures recorded outside the building. In the warehouse, the maximum temperature at the 16-foot elevation was usually several degrees higher than at 2 feet above floor level (table 1). With few ex- ceptions, temperature recorded at the 8-foot elevation was near the average of tempera- tures at 2 and 16 feet. The minimum daily temperature monitored at the three stations was consistently within a range of 3°F. This indicates that daily, after sunset or when there was a cloud cover, the warehouse temperature approached uniformity at the monitoring stations, Temperature difference in tobacco among the four vertically stacked hogsheads was minimal. Temperature in the top hogshead was usually slightly higher than the next-in-line unit. Tobacco temperatures at 12- and 20-inch depths in the top and bottom hogsheads generally did not vary more than 2°F, At the 4-inch depth, the temperature variation rarely exceeded 4°F. Fluctuation of tobacco temperature within any hogshead was greatest at the 4-inch depth in the top hogshead. (Figures 5-16 show these data.) "TIudvV pue ‘HOUVN ‘AUVONYEAA ‘XUVONVE SULInp o1nze1edule} ssnoyoreM UBeUl pue e8uvl d1njeV1odule} spIsynO--°Z einst A JUNLVAIdWIL ISNOHIYVM NVIW cccceseveecee SAVG JONVA JYALVYIdWIL IGISLNO SAVG lg TA 6l El l l l€ SZ 6l El l l *LSADNAV pue ‘ATONL ‘ANNE ‘AVI Sulainp oinyzetedure} osnoyeiem uvoul pue osuer oInyetodurey opisjnO--"¢ sANBI A JUNLVYIdWIL ISNOHIYVM NVIW eeecccceces JONVY JUNLVYAdWIL IGISLNO SAVG SAVG l€ SZ 6l | l l Ov oe) wn ~N a <2 Nn 09 08 09 08 001 “do “MAANATOAG pue ‘UAGNAAON ‘UAAOLOO “UAANALAAS ZuLinp o1meroduise} ssnoyoreM uBou pue aguel oinye1oduis, opIsnO--°PF 91NSt 7 JUNLVYIdWIL ISNOHIYVM NVIW cccccccccocce JONVA JUNLVAIdWIL AGISLNO SAV lg SZ 6l : El l l SAVG 4380190 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 Temperatures (OF.) at -- 2 feet above ; 8 feet above : 16 feet above Date floor level : floor level : floor level : Maximum : Minimum : Maximum : Minimum : Maximum : Minimum January: 1 50 48 50 48 50 47 2 o2 48 54 48 60 47 3 53 50 a3 50 56 49 4 ol 49 51 49 51 48 5) ol 46 Sy 46 56 44 6 52 45 54 45 61 43 7 52 47 54 47 58 46 8 54 52 DO 53 58 54 9 54 52 54 52 55 51 10 oo 49 54 49 56 48 jl Sy 46 55 46 60 44 12 51 44 54 44 59 42 13 53 46 59 46 67 44 14 52 Di 58} 51 53 50 15 53 50 53 51 54 50 16 54 49 60 50 66 49 oa | 54 46 60 47 67 44 18 ae 46 58 47 64 45 19 48 45 48 45 47 44 20 45 44 45 44 44 43 ZL 50 44 53 44 58 43 22 54 48 62 47 74 46 23 56 49 64 49 ee, 48 24 58 Die 68 OL 79 50 25 58 04 06 54 19 54 26 59 54 68 54 76 as] 27 59 56 65 DoD 70 56 28 55 51 60 51 64 50 29 55 49 59 49 65 48 30 54 50 54 49 61 48 BL BD 47 60 47 68 46 Average : 503 49 57 49 61 48 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 -- Continued : Temperatures (CF .) at -- 2 feet above : 8 feet above : 16 feet above Dake floor level : floor level g floor level : Maximum : Minimum : Maximum : Minimum : Maximum : Minimum February: 1 58 sY9) 66 57 76 56 2 58 53 65 54 71 52 3 BY 50 60 51 61 50 4 56 49 62 50 70 48 5 56 50 63 50 70 49 6 Ys) 50 60 50 66 48 7 52 49 53 48 54 A7 8 50 44 ¥5) 45 60 45 9 46 44 48 45 45 43 10 47 44 48 45 48 43 11 50 45 53 45 56 43 12 50 48 52 47 54 46 13 52 45 58 45 66 43 14 53 45 60 45 67 44 15 Ys) 52 62 53 68 52 16 56 54 62 56 68 56 iL 54 48 56 47 56 47 18 48 46 48 46 AT 45 19 49 45 49 45 50 45 20 48 45 48 44 47 43 2A : 2 46 ts}9) 46 61 46 22 : 50 43 53 43 58 42 23 : 51 46 54 46 60 44 24 g 50 45 504 45 08 44 25 : 46 40 47 40 50 38 26 : 48 39 ol 39 58 ast ul : 48 40 49 40 54 38 28 : 51 46 57 46 65 45 Average : 2 AT s}s) 47 50 46 11 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 -- Continued Temperatures (°F.) at -- Date 2 feet above : 8 feet above : 16 feet above floor level : floor level : floor level : Maximum : Minimum : Maximum : Minimum : Maximum : Minimum March: 1 50 45 5S 45: 52 43 2 50 42 56 42 64 50 3 54 48 64 48 74 47 4 Di 50 67 50 81 49 5 : 58 52 67 52 fh Bit 6 : 63 56 74 60 80 61 | : 61 56 69 58 76 59 8 58 54 66 54 74 52 9 59 52 68 52 78 51 10 58 a3 66 53 72 52 ah : 60 57 69 60 78 49 14 : 58 57 64 58 65 58 is : 60 56 66 56 73 55 14 : 62 58 70 60 80 59 LS : 63 59 15 60 88 59 16 : 60 50 67 56 76 55 17 : swe Spi 62 ah 67 51 18 : 56 48 60 48 68 47 19 : 56 47 61 47 a 46 20 : 54 48 55 47 58 46 21 : 8} sa | 53 51 ae 50 22 : 58 50 64 50 74 50 26 : Sy) 49 64 49 el. 48 24 : 58 Bil 65 52 15 50 25 : 59 54 66 54 76 53 26 : 62 54 vas) 54 87 53 Pat : 60 Bye 67 56 75 51, 28 : 61 56 69 56 79 56 29 : 63 58 70 60 78 60 30 ; 62 56 69 55 80 54 on : 62 54 12 54 86 53 Average : 58 53 66 53 74 52 12 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 -- Continued : Temperatures (°F.) at -- aie 2 feet above : 8 feet above : 16 feet above floor level : floor level : floor level : Maximum : Minimum : Maximum : Minimum : Maximum : Minimum April: 1 64 56 75 56 88 55 2 66 59 68 60 93 60 3 68 62 82 64 94 64 4 66 61 75 63 86 63 5 66 58 75 58 85 58 6 66 63 78 66 87 66 Ul 68 64 79 68 87 69 8 67 62 76 64 86 63 9 66 60 74 59 84 59 10 67 62 47 62 86 62 11 67 62 76 65 86 65 12, 66 59 13 59 84 58 13 61 59 64 59 66 58 14 67 60 76 60 86 60 15 68 64 77 66 86 66 16 (At 63 83 65 97 64 17 70 65 80 68 88 67 18 (fal 66 81 68 91 68 19 69 64 Chl 64 86 63 20 67 61 78 62 88 61 21 67 64 CE 61 87 61 22 65 62 75 68 83 68 23 67 61 70 63 70 64 24 66 60 76 62 87 62 PAS) 62 60 75 60 86 60 26 63 61 62 59 63 61 27 63 59 66 59 70 59 28 63 57 70 57 80 56 29 64 56 74 56 86 56 30 65 58 73 59 82 59 Average :; 66 61 79 62 84 62 13 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 -- Continued Temperatures (F.) at -- 2 feet above : 8 feet above : 16 feet above Date floor level : floor level : floor level : Maximum : Minimum :; Maximum :; Minimum : Maximum ; Minimum May: 1 67 62 78 64. 90 65 2 69 64 80 66 92 67 3 : 69 65 79 64 90 65 4 65 61 71 63 oe 63 5 66 61 76 61 87 63 6 66 62 74 64 80 64 i 66 64 74 68 80 67 8 66 60 15 61 85 61 9 65 60 M2 61 79 60 10 67 64 76 60 87 60 11 67 63 7p) 64 82 65 12 69 65 79 68 90 68 ils} 66 64 70 65 dat 65 14 68 63 78 64 89 64 15 70 65 81 68 91 68 16 69 64 79 66 90 66 1% 42 67 79 63 92 63 18 TA. 64 82 65 95 66 19 cL 65 81 66 93 67 20 73 67 85 (al 97 71 ZL 69 67 Ul 69 81 70 22 66 63 69 64 70 64 23 64 62 67 62 69 62 24 63 61 65 61 67 61 25 67 59 76 59 89 59 26 69 62 79 63 92 63 27 70 63 83 64 98 64 28 73 66 89 69 105 70 29 75 69 89 73 105 74 30 70 68 79 72 80 72 31 66 65 68 67 72 67 Average : 68 64 14 65 86 65 14 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 -- Continued : Temperature (°F .) at -- 2 feet above : 8 feet above : 16 feet above DEMS floor level : floor level : floor level : Maximum : Minimum : Maximum : Minimum ; Maximum : Minimum June: 1 66 64 69 64 72 65 2 65 63 67 64 70 64 3 69 63 79 63 90 63 4 : 70 65 79 67 88 67 5 : 71 66 81 68 90 68 6 : TP 67 83 69 94 69 a 33 67 84 69 95 69 8 75 67 82 69 102 69 9 76 69 89 71 103 72 10 Ua 70 90 2 106 72 11 : 76 71 89 73 104 74 12 : 78 71 91 74 104 74 13 : 79 US 92 ute 107 78 14 : 78 73 90 76 100 77 15 O 78 U2 90 75 102 76 16 ° 79 es 92 76 105 75 17 : 76 73 85 78 90 76 18 : 76 73 85 76 90 77 49 : 77 73 87 75 99 74 20 : 78 72 89 76 99 74 21 : 79 73 91 ad 104 76 22 : 79 74 89 79 101 79 23 ‘ 81 75 93 78 106 79 24 82 76 95 80 109 80 25 : 80 77 92 82 102 83 26 : 78 75 84 78 87 79 27 76 72 84 73 91 74 28 : 78 75 87 72 99 72 29 : 76 72 82 (83 89 73 30 : 76 73 . 84 76 92 76 Average : 76 71 86 73 96 73 15 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 -- Continued Temperature (°F.) at -- 2 feet above : 8 feet above : 16 feet above Date floor level : floor level : floor level : Maximum ; Minimum ; Maximum :; Minimum ; Maximum ;: Minimum July 1 79 73 91 ou 104 ff) 2 es 75 85 a 93 78 3 80 74 91 al 103 al 4 81 76 93 79 105 80 5 80 74 92 76 104 (HI 6 80 74 91 76 108 fe 7 78 75 87 78 95 79 8 719 75 89 78 101 78 9 81 75 92 78 104 78 10 81 76 91 79 101 80 11 81 77 91 81 101 82 12 82 “Gi 94 81 104 81 13 81 78 90 82 97 82 14 77 76 83 79 85 79 15 76 75 79 76 81 14 16 79 73 89 74 102 75 17 : 79 74 87 75 97 76 18 : 80 75 90 73 102 78 19 : 82 76 90 78 101 79 20 85 79 89 78 98 79 21 84 80 93 78 107 78 22 83 79 95 79 108 80 23 81 78 97 80 nb iy 81 24 83 76 96 81 109 82 25 84 80 94 83 105 84 26 81 79 94 82 105 82 27 80 76 97 81 110 82 28 82 75 94 83 103 84 29 83 77 92 83 100 84 30 84 77 88 80 94 80 31 84 78 94 i 106 78 Average : 81 76 91 79 101 79 16 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco ~warehouse, 1967 -- Continued : Temperature (°F.) at -- Date 2 feet above : 8 feet above : 16 feet above floor level : floor level : floor level : Maximum : Minimum : Maximum : Minimum ; Maximum ;: Minimum August: 1 84 79 96 81 109 82 2 86 78 97 81 111 82 3 86 81 98 83 110 84 4 86 81 97 84 109 85 9) 82 81 89 84 94 85 6 84 78 94 80 105 85 7 84 79 93 81 104 86 8 84 78 95 79 108 80 9 86 78 96 81 108 81 10 84 81 91 83 99 84 11 81 78 83 77 83 78 12 78 75 78 76 78 716 13 76 74 78 74 80 ae 14 80 13 87 73 99 73 15 80 74 89 74 99 74 16 82 75 92 75 104 15 17 82 77 92 78 103 79 18 88 78 93 80 106 80 19 84 79 94 81 106 81 20 84 79 94 82 104 83 21 83 79 93 81 105 81 22 80 78 85 80 88 80 23 80 at 85 78 90 78 24 82 78 40 78 101 78 25 85 77 95 78 111 78 26 84 77 95 81 107 m:}) 27 83 80 93 81 103 81 28 83 79 92 80 102 80 29 83 77 92 80 103 78 30 83 77 91 78 101 78 31 82 78 93 84 96 84 Average : 83 78 91 80 101 - 80 17 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 -- Continued Temperatures (°F,) at -- 2 feet above : 8 feet above : 16 feet above Date floor level : floor level : floor level : Maximum : Minimum : Maximum : Minimum : Maximum : Minimum September: Li 719 76 83 78 89 Ce 2 79 72 81 73 94 174 3 79 74 87 72 97 71 4 77 72 81 72 85 72 5 79 G2. 88 a2, 98 72 6 80 (es) 89 is 99 18) is 82 HE: 90 1(8} 102 1683 8 80 ae 89 ff) 101 13 9 78 76 83 uit 86 77 10 76 75 79 75 83 1D ata 15 73 79 (3 85 13 2 74 71 76 Th 80 ia 1333 76 ei 82 (al 90 70 14 re! 69 83 69 94 68 15 77 69 85 69 97 69 16 76 72 81 iZ 89 ( 1 74 (63 76 74 ae 73 18 78 73 87 74 98 73 19 79 as 90 i} 103 73 20 80 74 90 76 102 76 21 -- == 86 76 95 76 22, = -- 88 76 98 76 23 ae -- 84 12 92 72 24 == -- 83 68 92 68 25 = == 83 70 94 70 26 -- “= 85 68 97 68 27 76 68 82 76 89 73 28 76 68 84 1 92 15 29 Ve 68 85 {ts} 94 73 30 75 68 87 68 90 68 Average : 77 72 84 13 93 72 18 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 -- Continued aT SR aD TATU SP Uy DE TPT JS LSU su a : Temperatures ( F.) at -- 2 feet above 8 feet above : 16 feet above LEMS floor level : floor level ; tloor level : Maximum : Minimum ;: Maximum : Minimum : Maximum : Minimum October: 1 76 66 84 67 96 67 2 76 69 84 69 95 69 3 77 69 86 69 98 69 4 17 69 87 70 100 71 9) 78 71 88 71 100 71 6 78 72 87 72 100 72 Cf 73 72 74 106) 74 2 8 ie, 70 74 71 76 70 9 75 71 82 72 93 hie, 10 75 712 82 73 91 73 11 : 74 69 80 69 88 69 12 : 72 69 74 69 17 69 13 : 72 66 78 66 85 66 14 : 73 65 80 65 91 65 15 : 73 67 80 67 90 67 16 : UP 67 77 68 85 67 17 2 75 69 84 69 97 68 18 : 73 71 na 2 82 72 19 : 71 64 76 64 83 64 20 ° 71 62 17 62 86 62 21 2 71 62 17 62 87 62 22 Q 70 63 17 63 86 63 23 : 70 62 76 62 84 62 24 : 71 64 78 64 83 63 25 Q 70 66 tl 66 83 66 26 g 69 64 76 64 85 65 27 eS 69 61 76 61 85 61 28 g 67 63 70 64 74 63 29 : 67 58 73 59 82 58 30 67 59 74 59 83 59 31 : 66 59 70 59 76 59 Average : 72 66 78 66 87 66 19 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 -- Continued Temperatures (°F.) at -- 2 feet above : 8 feet above : 16 feet above Date tloor level : floor level : floor level : Maximum : Minimum : Maximum : Minimum : Maximum : Minimum November: i 70 62 75 62 | 85 62 2 67 65 69 65 Gh 65 3 68 62 74 63 82 62 4 67 62 {fs} 62 80 62 5 65 58 69 58 76 58 6 62 55 62 56 67 55 fi 61 53 62 53 70 53 8 60 ol 64 ol 68 51 9 60 51 64 52 71 51 10 62 54 69 54 80 54 11 : 62 55 65 55 ie. 55 12 : 63 56 70 56 78 56 13 : 62 59 64 59 69 59 14 : 62 56 67 56 79 56 15 : 62 54 65 54 i 53 16 : 58 51 60 Sir 65 50 17 : 58 50 61 50 66 50 18 : 59 52 65 53 71 52 19 : 59 93 64 54 70 53 20 : 58 51 63 52 i 51 21 : 58 53 62 54 69 53 22 : 58 55 58 56 59 54 3 : 61 57 65 57 72 57 24 : 55 53 55 53 55 53 25 : 61 56 67 55 76 55 26 : 61 54 69 64 79 53 27 : 59 58 60 58 62 58 28 : 58 52 61 52 66 52 29 : 57 49 62 49 69 49 30 : 53 52 54 53 53 52 Average : 61 55 65 57 71 55 20 TABLE 1.--Maximum and minimum temperatures at three elevations in a tobacco warehouse, 1967 -- Continued Temperatures (’F.) at -- 2 feet above : 8 feet above : 16 feet above Date floor level : floor level : floor level : Maximum ; Minimum ; Maximum : Minimum ; Maximum ; Minimum December: 1 55 50 57 51 63 50 2 55 48 58 48 65 AT 3 57 53 58 54 62 54 4 57 50 62 51 71 50 5 57 48 64 48 73 48 6 57 50 62 50 70 50 7 58 52 63 52 71 52 8 59 55 64 55 71 55 9 58 54 60 54 65 54 10 57 56 a7 06 58 56 11 : 56 54 56 55 57 55 2, : 59 56 64 56 70 56 13 : 59 52 65 53 74 52 14 : 59 51 65 ol 74 51 15 : 59 56 61 55 68 56 16 : 57 50 60 49 68 49 17 : 57 48 62 48 71 48 18 : 57 53 56 53 59 53 19 : 59 57 61 56 | 68 57 20 : 59 57 62 57 66 58 21 : 60 56 66 57 69 57 22 : 61 58 69 60 75 59 23 C 58 49 60 55 59 50 24 Q 54 46 58 48 64 AT 25 : 54 47 58 49 62 48 26 : 54 49 59 51 65 50 27 : 54 AT 57 48 62 48 28 : 52 50 52 50 52 50 29 : 53 48 57 48 62 48 30 : 53 46 56 46 63 46 31 : 50 47 50 47 50 47 Average :; 56 51 59 52 65 52 21 JANUARY ol _ Pato wi ae aC | SECOND FROM TOP | > oO | THIRD FROM TOP | TEMPERATURE, °F. an L—] 4” DEPTH — — 12” DEPTH —— 20° DEPTH “DAYS Figure 5.--Temperatures of tobacco prized in hogsheads racked 4 high in a warehouse during JANUARY. FEBRUARY 60 — ——— — [ SECOND FROM TOP 40 60 TEMPERATURE, °F. 80 BOTTOM eeee 4” DEPTH —— 12” DEPTH —— 20” DEPTH og oasis tt lb eanr reset Oe tease rit 1 7 13 DAYS 19 25 3] Figure 6.--Temperatures otf tobacco prized in hogsheads racked 4 high in a warehouse during FEBRUARY. 22 60 Soap . nm “eccccccccce” | i 40 60 SECOND FROM TOP | od > o TEMPERATURE, °F. ecco = 4” DEPTH —— 12" DEPTH —— 20” DEPTH ae 7 B pays 9 25 31 Figure 7,.--Temperatures of tobacco prized in hogsheads racked 4 high in a warehouse during MARCH. APRIL TEMPERATURE, °F. ecce 4” DEPTH —— 12” DEPTH — 20” DEPTH 0008 29kn oe Figure 8.--Temperatures of tobacco prized in hogsheads racked 4 high in a warehouse during APRIL. 23 Figure 9.--Temperatures of tobacco prized in hogsheads racked 4 high +E: Figure 10.--Temperatures of tobacco prized in hogsheads racked 4 high TEMPERATURE, °F. TEMPERATURE, SECOND FROM TOP 80 a ° THIRD FROM TOP fe] oO ~~ *o, ~ Peoee® 60 100 BOTTOM 4” DEPTH —— 12” DEPTH — 20° DEPTH 80 60 in a warehouse during MAY. Oa | at THIRD FROM TOP == . oot 60 100 p>— BOTTOM 7 eee 4” DEPTH 12” DEPTH 80 PPeccece — in a warehouse during JUNE. 24 80 ° eB | : THIRD FROM TOP 60 | je , E SECOND FROM TOP °_ 60 TEMPERATURE, °F ecco 4” DEPTH Ze DERTH —— 20” DEPTH 80 Figure 11.--Temperatures of tobacco prized in hogsheads racked 4 high in a warehouse during JULY. AUGUST TEMPERATURE, °F. ecce 4” DEPTH —— 12” DEPTH 2 On DER TH 60 pti tii 5 --<= Cocecer® e eoee ®eeeo® DAYS 19 25 3] Figure 12.--Temperatures of tobacco prized in hogsheads racked 4 high in a warehouse during AUGUST. 25 SEPTEMBER _ a eg J eee eooe e Peccoseg cee? Se% Seleeteted ° e ecee Seoocecse®® uid [Le ine nas FROM TOP | 80 ° Re eae ok: —— —$_ —— ] TEMPERATURE, 100 7 |_ THIRD FROM TOP : 80 =~ = Se — ° =_——= fee a = | *Peecescconeoen® *eecccsace™ Se 1 n 4” DEPTH 12” DEPTH 20” DEPTH 100 Poccccccsesore™ = LS “Pees cccaccoore® PS eeccwcce® -. BOTTOM | 60 a a Te | ey Hcl Ea | ea a oat [eee et ee) fT Ey ] 7 13 19 25 3 DAYS Figure 13.--Temperatures of tobacco prized in hogsheads racked 4 high in a warehouse during SEPTEMBER. OCTOBER . —S=> fo qoe??P oy, —== *eCegeecceece® = ° e Peevcccccac®® %% fee SECOND FROM TOP 80 ‘° ——— ° = Peoet*Pee.y, — ° e Pecce eco? a o THIRD FROM TOP TEMPERATURE, °F. °; ecoe 4” DEPTH —— 12° DEPTH — 20” DEPTH Steg | | icgetntaeae “eeccceees (ee i ae Litt | 1 7 3 DAYS ss q Figure 14.--Temperatures of tobacco prized im hogsheads racked 4 high in a warehouse during OCTOBER. 26 NOVEMBER >So —-—-—— — Perc eccccesevovetee —. Coooe® Pa peceeerreccet®” Meeeee | °F. TEMPERATURE, BOTTOM eoce 4” DEPTH —— 12” DEPTH — 20” DEPTH 1 7 13 DAYS 19 25 ol Figure 15,--Temperatures of tobacco prized in hogsheads racked 4 high in a warehouse during NOVEMBER. DECEMBER SECOND FROM TOP ~=~— === e e OG00900 Pooctece, _—_— _—= PS0esoog THIRD FROM TOP TEMPERATURE, °F. = °. --— == 2000 == Cee cccccg,, ° ecee 4” DEPTH == 12” DEPTH =—— 20” DEPTH = oote Saceoeee BOTTOM | ] 7 13 19 25 31 Figure 16.--Temperatures of tobacco prized in hogsheads racked 4 high in a warehouse during DECEMBER. 27 The relative humidity inside the warehouse was nearly identical at all three moni- toring stations. The relative humidity range inside the warehouse throughout the year was consistently between 40 and 60 percent (figs. 17-20). The daily average outside relative humidity fluctuated widely; whereas, the warehouse relative humidity remained more stable. The average outside relative humidity generally was over 60 percent, but humidity was rarely this high inside the warehouse, Moisture in flue-cured tobacco increases during the first 2 or 3 years in storage if moisture is between 10 ve 11 percent when tobacco is prized. According to Dixon, Darkis, Wolf, and others® the peak moisture gain coincides with the peak development of natural aroma. Data from our study show that during the first year of storage, the tobacco moisture in the hogsheads at the depths monitored increased from 0.6 to 2.9 percent (table 2). During the year, tobacco in each hogshead gained moisture. Mois- ture content increased gradually and in a consistent pattern. Throughout the year, the hogshead second from the top was lowest in moisture content. The hogshead third from the top was consistently the highest in moisture content. However, if the moisture gain for hogsheads in each of the four heights is averaged, the units with the highest moisture gain are the hogsheads second from the top and on the bottom. The hogsheads with the least gain are those that had the highest moisture level soon after being stacked. 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Ov |_— y ; 09 32 TABLE 2.--Percentage of moisture, wet basis, of grade B4F, 1966-crop flue-cured tobacco packed in hogsheads and stored in Wilson, N. C. : Percentage of moisture (wet basis) from -- : Second : Third Date of : Top : hogshead : hogshead : Bottom registry : hogshead : from top : from top : hogshead T4einkes Lapin payne so P2hin,, eso 4aeing 3 T2hin, 34 in.) 12) in. DANUATY). gc) 2) LORS -~ 9.4 -- 12.3 -- Zee -- He: LOR -- 9.4 a= 12.3 -- 12 -- 132: Ons 10.8 9.8 10.0 12.3 11.2 12.3 9.8 Psy, SP JIL) 11.7 10.0 10.8 12.5 12.3 teh 7 10.8 February... 1 : 11.2 Shee slay 19 1D alee 1 Beside 2 il air 1 gune....... ¢ : 11.2 11.9 10.8 11.0 12.7 12.5 12.1 11.5 Mee LL) 11.7 10.6 11.0 12.3 12.1 12.1 ent BeBe Me 11.9 10.8 11.2 12.5 12.3 12.3 11.9 28 : 11.5 12.3 11.0 MDL 12.5 12.7 12.3 12.1 July........ 5 : 11.9 12.3 11.2 11.7 12.5 12.7 12.3 12.1 Wy 8 AN 12.3 10.8 11.9 12.5 12.7 12.3 12.1 ag) tts 12.5 11.0 11.9 12.7 12.9 12.5 12.3 26 : 11.7 12.5 11.2 11.9 12.7 12.9 12.5 12.3 33 TABLE 2.--Percentage of moisture, wet basis, of grade B4F, 1966-crop flue-cured tobacco packed in hogsheads and stored in Wilson, N. C. -- Continued : Percentage of moisture (wet basis) from -- : Second : Third Date of : Top : hogshead : hogshead : Bottom registry : hogshead : from top : from top : hogshead ‘ Ains = 12 in, : 4iny = Zan, +: fing © -l24an. 4. 44in, een. : deep : dee : dee dee : dee dee : deep : dee September... 7 + 12.1 12.7 11.5 12.3 12.9 13.3 12.7 19 13: 12.3 12.9 sy a 12.3 13.1 13.3 12.9 124 20 2 12,3 12.9 1159 12.3 13.3 13,5 12.9 12, Zt: 12.3 12.9 11.9 12x03 13.3 13.0 12.9 Zk October.... 4 : 12.3 12.9 £7. % 12.3 12.9 13.5 120 12.3 1 eee A 12.9 11.9 12.5 13.4 13.5 2 12.3 ES? = 1250 13.1 i 12.5 13.4 13.5 oe | 12.3 25 : 12.5 13k 1159 12.7 13st 13.5 1267 12.3 November.. 1 : 11.9 5 | 11.5 11.9 12.9 13.3 12.9 12.3 December.. 6 : 12.1 12.7 11.5 11.9 13.3 ss Ta 13:3 I PAP | £32: 1268 12.7 AS 12,1 134% 13.5 Loe APART 20) ¢ 1264 12.7 11,5 1251 1S 13.5 13,1 12 4 at 2 12,1 12.9 11,5 12. 12.9 13.5 13.3 12.7 Moisture gain for year ae 2.1 Pipe 2.1 0.6 2.3 12 2.9 Average gain of both depths: 1,9 ’ 2.1 1,4 2.0 34 UNITED STATES DEPARTMENT OF AGRICULTURE Agricultural Research Service Hyattsville, Maryland 20782 Official Business POSTAGE & FEES PAID Penalty for Private Use, $300 United States Department of Agriculture