AMERICAN TOBACCO TYPES, USES, AND MARKETS 95 
tions, has an important effect in mellowing it and enhancing the 
aroma. A part of the nicotine content is lost by volatilization during 
fermentation. 
The most widely used type for the manufacture of pipe tobacco is 
Burley. Some of the most widely distributed brands of smoking 
tobacco are made exclusively of that type, and probably few do not 
include some Burley. Many brands are blends of selected grades of 
numerous types. 
TOBACCO BYPRODUCTS”? 
MATERIALS USED 
Large quantities of offal accumulate in the handling and manufac- 
turing of tobacco. The principal items of offal tobacco are as follows: 
Stems.—Stems, as they are commonly known, are the midribs of 
tobacco leaves. (See fig. 37, p. 79.) In nearly every manufacturing 
use most of the stems are removed. The only exceptions relate to 
snuff, where the whole leaf is ground, and to Turkish tobacco used in 
cigarettes. The leaves of Turkish tobacco are so small that removal 
of the stems is unnecessary. Stems represent approximately one- 
fourth of the weight of the leaf, the actual percentage for specific 
types varying from 17 to about 30 percent (22). In addition to 
stems accumulating in tobacco factories, considerable quantities of 
tobacco are stemmed for export. As a result of these two classes of 
operations it is estimated that from 180 to 200 million pounds of 
stems become available each year for manufacturing purposes and 
export. Exports of stems normally range from 15 to 20 million 
pounds annually. Relatively small quantities are added to leaf to- 
bacco in the manufacture of snuff, and indeterminate though small 
quantities are softened by steaming or soaking, flattened by rolling, 
and used in various tobacco products. The byproducts industries 
absorb from 80 to 90 percent of available stems. 
Scraps, Cuttings, and Clippings.—This class includes factory and 
warehouse scrap, damaged leaves, and other waste products not 
suitable for use in ordinary tobacco products. 
Dust and Siftings—Tobacco as it is received from the farm at 
redrying plants, dealers’ packing houses, and factories, often has 
fine soil particles clinging to it. This may be road dust carried by 
wind, or fine soil particles thrown up on the lower leaves ‘by storms or 
in the course of field operations. One of the necessary operations in 
all processing plants is to shake out each hand or bundle of tobacco 
to loosen the leaves and remove the dust and fine sand, or to put it 
through cleaning machines which accomplish the same result. Inevy- 
itably small particles of tobacco are loosened at the same time. From 
2 to 5 million pounds of dust and siftings are developed annually in 
this operation. 
BYPRODUCTS MANUFACTURED 
The principal byproducts of the tobacco industry are fertilizer, 
nicotine for insecticides, and tobacco extract for flavoring. 
Fertilizer —Tobacco stems when finely ground and sterilized are 
used in the manufacture of mixed fertilizers as a conditioner to give 
the mixture easy-flowing properties, and as a source of organic potash. 
19 For a more exhaustive discussion of tobacco byproducts, see ‘‘EXPORT TRADE IN AND BYPRODUCTS 
USES OF TOBACCO”’ (28), 
