BULLETIN OF THE 



No.79 



Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief, 

 April 23, 1914. 



(PROFESSIONAL PAPER.) 



RESEARCH STUDIES ON THE CURING OF LEAF 



TOBACCO. 



By W. W. Garner, Physiologist in Charge, C. "W. Bacon, Assistant Physiologist, and 

 C. L. Foubert, Assistant in Tobacco Chemistry, Tobacco and Plant-Nutrition 

 Investigations. 



INTRODUCTION. 



The term " curing," as applied to tobacco, is somewhat indefinite 

 in meaning, being used sometimes to include the separate operations 

 of barn curing, fermentation, and aging, or afterfermentation, while 

 the farmer usually restricts the term to the process of drying the ripe 

 leaf in a specially constructed barn and under such conditions as 

 will develop the desired properties or qualities. In the present 

 article the term is used in the last-named more restricted sense, so 

 that we have only to consider curing as far as it proceeds in the 

 curing barn. 



The methods now in vogue in barn curing are almost entirely 

 empirical, being the result of practical experience extending through 

 several generations, and in general are based more or less on rule-of- 

 thumb procedures, without sufficient flexibility to meet changing 

 conditions and requirements. The barn curing of tobacco has not 

 received the attention from investigators that has been given the 

 subsequent process of fermentation, and such investigations as have 

 been made relate mostly to certain special phases of the subject. 



There are two general methods of harvesting tobacco and arranging 

 it in the barn which materially affect the results obtained in curing. 1 

 In the one case the leaves are picked from the stalk as they mature 

 or "ripen" and are arranged on strings or sticks suitable for hanging 

 in the curing shed, this method being popularly spoken of as priming. 

 In the other method the leaves are not removed from the stalks, but 

 the latter are cut off near the ground and suspended in an inverted 



1 For details of these methods consult Garner, W. W., Principles and practical methods of curing tobacco, 

 U. S. Department of Agriculture, Bureau of Plant Industry, Bulletin 143, 54 p., 10 fig., 1909. 



Note.— This bulletin gives the results of a study of the physiological changes occurring in curing 

 tobacco in the barn and is of special interest to those concerned with the improvement of tobacco curing. 



29731°— 14 1 



