US2353718A

US2353718A - Tobacco

Info

Publication number: US2353718A
Application number: US451962A
Authority: US
Inventors: Garber Thomas Hollingsworth
Original assignee: Larus and Brother Co Inc
Current assignee: Larus and Brother Co Inc
Priority date: 1942-07-22
Filing date: 1942-07-22
Publication date: 1944-07-18
Anticipated expiration: 1961-07-18

Description

5 STAGE y 18, 1944- "r. H. GARBER 2,353,718

TOBACCO Filed July 22, 1942 5 Sheets-Sheet l I STAGE 2' STAGE sumsuz 0F onvs END OF \a STAGE END OF 2125mm END OF see s'r e 10 TO 30 DHYS IO TO '50 DAYS IO TO 50 DAYS 4 Thomas H. Garbeg auW July 18, 1944. GARBER 2,353,718

TOBACCO Filed July 22, 1942 3 Sheets Sheet 2 5 STAG (i mmu-ras E 2 In szn's'saad Elm-mew )amnaw saw om QAUG 0Q 01 G0\2\3d DNHOOD 2 STAGE MINUTES I g STAGE MmuTes Patented July 18, 1944 PATENT OFFICE? TOBACCO Thomas Bollingsworth Gerber, Richmond, Va., assignor to Laura and Brother Company, Inc.,

Henrico County. Va.

Application July 22, 1942, SerialNo. 451,962

13 Claims. :(Cl. 131-440) This invention relates to tobacco and more particularly to a method or process of accelerating the aging of tobacco.

The practice of aging all types of tobacco has long been used by the tobacco industry in order to develop the desirable qualities of color, aroma, and burning qualities which are required for use in manufactured tobacco products.

Under present methods employed by the tobacco industry, cured tobacco including flue cured, air cured, and sun cured types as purchased from the farmers or growers is graded, blended, stemmed or left unstemmed, then uniformly dried to a pre-,determined moisture content to 12% moisture) after which the tobacco is prized by types and grades into hogheads containing chemical composition of the tobacco is changed from 800 to 1000 lbs. of tobacco. The hogsheads are placed in open or closed types of storage warehouses of standard construction, located in a suitable section for desirable atmospheric conditions and allowed to remain in storage from 1 /2 to 3 years or more, depending upon the type of tobacco. During this variable storage period the natural aging process takes place, resulting in chemical and physical changes in the composition of the tobacco, depending upon the atmospheric or seasonal variations in temperature and relative humidity which occur throughout the year in the tobacco storing areas. It is generally assumed that these atmospheric changes cause two seasonal "sweats annually-that is, an increase in the moisture content and temperature of the tobacco from the surrounding atmospheric conditions. The degree of the natural aging process of tobacco is dependent upon the length of time in storage and the atmospheric conditions prevailing during this period with relation to the chemical composition of the tobacco.

When cured tobacco is properly aged or mellowed" from the commercial viewpioint, (1) it should be devoid of the green, hay-like odor and the irritating and disagreeable smoking qualities possessed by unaged tobacco; (2) it should possess a rich, full aroma whichwill naturally enhance the value of the finished products; (3) it should possess a color, texture, and "body" in line with trade requirements (4) it should have sufflcient elasticity and pliability to allow handling without undue loss from breakage; (5) the During the aging period with the associated seasonable variations, the tobacco undergoes both A physical and chemical changes while in storage,

in many respects, as for example, by a lowering of the nicotine, total nitrogen, alpha amino 'nitrogen, water soluble nitrogen, total non-volatile acidity, total sugars, and the hydrogen ion con centration or pH of the tobacco. Likewise, with the lowering in the above, there is an increase in the moisture content of the tobacco. By these chemical changes there is a definite improvement in the texture, color, and aroma of the tobacco which is so necessary before use can be made of at various rates, therefore, depending upon-theinitial chemical composition, the initial moisture content, and the temperature at which the tobacco is aged. With the aging of tobacco by seasonal changes in temperature and relative humidity,

' some tobaccos are well aged at the expiration of one and one half-(1V2) years, whereas others require two (2) or three (3) or more yearsin order to properly possess the aging qualities with a loss of all rawness and acquirement of full aroma. It has been found that aging is usually pro portional to the initial moisture content of thetobacco when placed in storage. Therefore, the process for fully aging tobacco has been found to be regulated or determined by control of the initial moisture content, the length of time in storage, and the temperature of the tobacco during the storage period.

It will be readily understood that when tobacco isaged in the conventional manner described above, it may easily require three years or more to obtain the desired efiects in color, aroma, and smoking qualities with the associated chemical composition, and assuming an average price of tobacco of approximately twenty cents (20) per pound, millions of dollars in capital can be tied up for these relatively long periods. Also, supplies of commodities are ofttimes cut off or interferred with to the extent that it is desirable to be able to put on the market tobacco products grown only a short time before. This lengthy storage period for carrying out the aging also causes numerous additional problems and costs, such as control of tobacco insects, prevention of mold, flre hazards, insurance, etc.

It is an object of this invention to accelerate the aging process of tobacco and likewise decrease the time required for aging where it is desired to obtain the essential color, aroma, mildness, and lack of greenness--so recognized as prerequisites for ,properly aged tobacco. The herein described process is carried out preparatory to the production or manufacture of tobacco products and follows after grading, blending, stemming, drying, and prizing into hogsheads for storage.

All of the desired chemical changes occurring in the natural aging of tobacco under the present means employed in the tobacco industry are carried out by the present process.

It is a further object of the present invention not only to reduce the time required for aging of tobacco from the customary 1 to 3 years to approximately 3 to weeks, depending upon the use of the herein described method, but also to control the chemical changes taking place in the aging process of tobacco for uniform results prior to utilization of same in the manufacture of tobacco products.

From results obtained by the herein described method, tobacco, both air-cured and flue-cured, possesses all of the characteristics of fully naturally aged tobacco acceptable to the tobacco industry for use in the manufacture of tobacco products.

The aging of tobacco by the process of the present invention can be controlled for a particular type of tobacco, requiring different treatment, with. a variable period of aging which offers an improvement over the long-time process.

The foregoing and other objects and advantages. of the herein-disclosed process will become apparent in view of the following description taken in conJunction with the drawings, wherein:

Fig. 1 is a chart showing the approximate ternperature and moisture content of tobacco during three stages of treatment of the present process;

Fig. 2, a chart which may be used as a guide in controlling the temperature and relative humidity of the air during said process;

Fig. 3, a chart which may be used as a guide when carrying out the process of the present invention in a vacuum chamber;

Fig. 4, a chart illustrating changes in the chemical composition of tobacco during the respective stages of the present controlled aging process; and

Fig. 5, a chart similar to Fig. 4 but showing chemical changes during natural aging of tobacco.

The temperature of the tobacco in the hogsheads is uniformly increased to approximately 110 F. with a moisture content of approximately 13% to 13%% moisture and then allowed to cool in storage for 10 to 30 days depending upon the method of cooling. The tobacco in the hogsheads is again processed that is the temperature of the tobacco is uniformly increased to 100 F. and the moisture content of the tobacco is increased to 12 to 13% moisture. The tobacco in the hogsheads is then allowed to cool in storage from 10 to 30 days. Finally, the tobacco in the hogsheads is subjected to a uniform temperature of F. with a moisture content in the tobacco of 12% to 12 /2% moisture and then gradually cooled to atmospheric conditions in a period of 10 to 30 days.

The chart of Fig. 1 gives the approximate moisture content of the tobacco and corresponding temperatures during the above three stages of treatment, while in Fig. 2 a chart is shown which may be used as a guide in controlling the temperature and relative humidity of the air to obtain the factors of Fig. 1. It will be understood that these charts are only approximations, since treatment may vary subject to different types of tobacco, method and apparatus used for treatment and results to be obtained.

The time of the cooling period is variable depending upon the method of cooling-that is, whether the tobacco is allowed to cool under atmospheric conditions or whether the use of refrigeration or circulation of air to decrease the temperature of the tobacco more rapidly is used. Both methods of cooling work satisfactorily.

The foregoing successive stages of forced or accelerated artificial aging compares favorably with, or is the equivalent of two to three years of natural aging. The time required by the process outlined may vary from 30 to 90 days.

The following constitutes a practical method and means or apparatus for carrying out the aging treatment, reference being had to Fig. 3:

Tobacco in hogsheads or in bales is placed in a specially constructed vacuum chamber of sufficient size depending upon the capacity of the equipment. The chamber is connected to the suction of a steam Jet evacuator or air pump. The chamber is evacuated to a point of approximately 295' of mercury vacuum pressure or .5" of mercury absolute pressure. After evacuating the chamber containing the hogsheads of tobacco, which of course reduces the volume of air content within the hogsheads to the same density as the air surrounding the hogsheads within the chamber, steam is then admitted into the chamber. Due to the higher relative pressure, the steam will flow immediately all through the tobacco in the hogsheads with the possible exception of a small area in the center.

When steam is admitted into the vacuum chamher, it enters the hogsheads from all sides and flows in towards the center of the hogsheads, thereby uniformly increasing the moisture content and temperature of the tobacco. The steam is admitted into the vacuum chamber until the absolute pressure is raised to 10" of mercury which corresponds to a vacuum pressure of 20" of mercury. This condition is maintained for a period of approximately three minutes in order to allow the steam or moisture to penetrate throughout the tobacco in the hogsheads. At the end of this time the steam supply is cut off and the chamber is evacuated to a predetermined absolute pressure for regulating the final temperature and moisture content of the tobacco as further described.

The tobacco in the hogsheads inside of the chamber at the time of steaming comes into equiin the hogsheads has been cooled to 110 F.) At

this point the vacuum is released and air is admitted to equalize the pressure so that the door can be opened and the tobacco removed. The

tobacco in the hogsheads is checked for temperature and moisture content and then allowed to remain in storage for the cooling cycle under atmospheric or accelerated means. This completes the first stage of the aging process.

During the second stage of the method, the chamber is evacuated as described in the first stage and steam is allowed to enter the hogsheads under the same conditions as above after which the chamber is evacuated to an absolute pressure of approximately 2" of mercury which corresponds to a tobacco temperature of 100 to 101 F. The vacuum is then discontinued, air is admitted as before into the vacuum chamber, the tobacco removed for the second stage of cooling, and the end of the second stage of aging.

During the third stage of aging the chamber is evacuated as described above and steam is allowed to penetrate throughout the tobacco at an absolute pressure of of mercury for a period of three minutes after which the chamberls evacuated or reduced to an absolute pressure of approximately 1" of mercury wherein the corresponding tobacco temperature is 90 F. The vacuum is discontinued at this point and air is admitted into the chamber, the tobacco removed. and the tobacco is allowed to cool to atmospheric temperature for the completion of the third stage 01' the aging process.

Depending upon the type of equipment used for producing the temperature and moisture content of the tobacco, the time required for this part of the process is variable. However, the entire cycle usually requires from to minutes with the proper equipment.

The corresponding moisture contents desired in each stage of the process will be obtained automatically by operating under the foregoing conditions, that is, during the first stage the tobacco will contain approximately 13% to 13. moisture when released at 110 F. During the second stage the tobacco will contain approximately 12 /2 to 13% moisture when released at 100 F. During the third stage the tobacco will contain approximately 12% to 12/2% moisture when released at 90 F., after which it will undergo cooling after each stage under atmospheric or controlled cooling conditions.

The absolute values used in the process may be required to be changed as diflerent types or grades of tobacco are processed in that they may require different pressures and temperatures to secure the best results. a

This method of controlled aging can be carried out also by means of storing tobacco in hogsheads or bales in a conditioning room or -sweating room wherein the temperature of the tobacco can be raised uniformly by artificial heat from the air and the moisture content of the tobacco increased uniformly by controlling the relative humidity of the air. Since tobacco absorbs heat and moisture readily, this method has been that the time required is somewhat longer due to the time required for penetration of the moisture and temperature throughout the hogsheads of tobacco as compared to the method described herein of adding the moisture and temperature by diflerences in pressure after evacuating the air from the chamber wherein the tobacco has been placed.

Obviously there are methods and apparatus other than those above described which would work satisfactorily for increasing the temperature and moisture content of tobacco to the uniform specifications in order to carry out the aging process, it being understood that this invention covers all such methods wherein the effects of controlled temperature and moisture content and the cooling period may be regulated to accomplish the results and chemical changes of aging.

The resulting effects of this method of controlled aging of tobacco produce identical physical and chemical results as when tobacco undergoes the natural aging process, note the charts of Figs. 4 and 5 which are self-explanatory. It has been found that the associated chemical changes taking place during aging, namely with the reduction in nicotine, total nitrogen, alpha amino nitrogen, water soluble nitrogen, total nonvolatile acidity, total sugars, and the hydrogen ion concentration, take place with the resulting increase in moisture content of the tobacco as is the case with tobacco after the natural aging process. In like manner the physical characteristics of tobacco have been found acceptable in that the tobacco is devoid of the -green haylike odor and the irritating and disagreeable smoking qualities possessed by unaged tobacco and also that it has a rich, full aroma with color and texture in line with trade requirements.

The greatest change in the chemical composition of tobacco under the natural aging process process, that is the raising of the temperature to approximately 100 F. at 12% to 13% "moisture and then cooling, accomplishes the results of the second year of natural aging.

Finally, the stage of raising the temperature to approximately F. at 12% to 12% 2% moisture and then cooling results in changes corre-.

sponding to the third year of natural aging.

Since some tobaccos age faster than others, it is sometimes desirable to stop the controlled asing process at the end of the second stage. Particularly would this be true in the case of processing bright or flue cured tobaccos of high carbohydrate content which increases the development of the aging characteristics. In the case of burley or air cured tobaccos usually the full three stages of controlled aging are required to produce the equivalent of three years of natural aging for the best results.

It will be understood that the data herein set forth by way of descriptive matter and accompanying charts are for illustrative purposes only and are not to be construed as limitations, the scope of the invention being defined by the appended claims.

What is claimed is:

1. In the processing of tobacco, the method of accelerating aging which consists in artificially increasing the temperature and moisture content of the tobacco and permitting the tobacco to cool, again artificially increasing the temperature and moisture content but to a lower degree and again permitting the tobacco to cool, and if necessary repeating the cycle until the desired chemical changes are attained. v

2. In the processing oi. tobacco, the method of accelerating aging which consists in storing tobacco in a suitable container such as a hogshead and while so stored, artificially heating the tobacco and increasing the moisture content and permitting the tobacco to cool and repeating the cycle until aging is completed, the heating temperature of each successive cycle being lower than the preceding cycle.

3. In the processing of tobacco, the method of accelerating aging which consists in storing the tobacco in a suitable container such as a hogshead, heating the tobacco to a temperature approximating 110 F., then allowing the tobacco to cool, again heating the tobacco to a temperature of approximately 100 F. and permitting the tobacco to cool, and thereafter subjecting the tobacco to a final heating to a temperature of approximately 90 F. and gradually cooling, the moisture content of the tobacco reaching a maximum during the first cycle oftreatment and being progressively reduced through each cycle.

4. In the processing of tobacco, the method of accelerating aging which consists in subjecting th tobacco while in storage to successive heating and cooling periods while simultaneously controlling the moisture content until aging i completed, the temperature of each heating period being progressively reduced with respect to the temperature of the preceding heating period.

5. In the processing of tobacco, the method of accelerating aging which consists in placing the tobacco in a closed chamber, evacuating air from said chamber to a predetermined absolute pressure in inches of mercury, then admitting steam into the chamber until the pressure is raised to a point substantially corresponding to a vacuum-of approximately 20" pressure, maintaining such pressure for a short soaking period in order to permit the steam or moisture to penetrate throughout the tobacco, then cutting off the supply of steam and again evacuating the chamber to cool the tobacco to a predetermined final temperature and moisture content, and repeating the cycle with successively lower final tempera: ture and moisture contents until aging is completed.

6. In the processing of tobacco, th method of accelerating aging which consists in placing the tobacco in storage containers such as a hogshead, placing the hogshead in a vacuum chamber, evacuating the chamber of air to a point s,sss,71a

substantially corresponding to 29.5" or vacuum, then admitting steam into the chamber and permitting the steam to penetrat substantially throughout the tobacco in the hogshead, cutting on the supply oi steam and again evacuating the chamber to an absolute pressure of substantially 2.6" to thereby determine the final temperature and moisture content of the tobacco, and repeating the cycle of treatment with successively lower final pressures until aging is completed.

'7. The method of accelerating aging which consists in artificially increasing the moisture content and the temperature of tobacco while maintaining for one period a definite ratio of temperature to moisture content, thereafter cooling the tobacco by decreasing the temperature and moisture content while maintaining a diner-- ent ratio of temperature to moisture content during such cooling period and then increasing the temperature and moisture content of the tobacco while maintaining a ratio of temperature to moisture content different from the first two periods.

8. The method of aging tobacco in accordance with claim 7 wherein the ratios are progressively reduced.

9. The method of aging tobacco in accordance with claim 7 wherein the temperatures are proressively reduced.

10. The method of aging tobacco which consists in artificially heating and cooling the tobacco in at least three successive stages and maintaining a different ratio of temperature to moisture content in each stage.

11. The method of aging tobacco which consists in subjecting the cured tobacco to a plurality of treatments and controlling the moisture contentthereof, each treatment including artificially heating the tobacco and likewise cooling the tobacco and each heating being to a slightly less temperature than the preceding heating.

12. The method of aging tobacco which consists in subjecting the cured tobacco to a plurality of treatments, each treatment including artificially heating the tobacco and likewise cooling the tobacco and each treatment comprising a different ratio of temperature to moisture content.

13. In the processing of tobacco, the method of accelerating aging which consists in storing the tobacco in a suitable container such as a hogshead, heating the tobacco to a temperature of approximately 110 F. with a moisture content of 13 to 13 /2 per cent, allowing the tobacco to cool in storage for between ten to thirty days, again heating the tobacco to a temperature or approximately 100 F. at a moisture content of approximately 12 to 13 per cent, and allowing the tobacco to cool for a period of between ten to thirty days, and finally subjecting the tobacco to a temperature of F. at a moisture content of 12 to 12% per cent and gradually cooling over a period of ten to thirty days.

THOMAS HOILINGSWORTH GARBER.