nw 
bo 
root itself, is fermentable. On this as- 
sumption a ton of roots should produce 
about 42 gallons of alcohol. At $5 per ton, 
which would be a fair price with modern 
methods of cultivation, the raw material 
would cost about 12 or 13 cents per gal- 
lon of alcohol. That technical difficulties 
might arise in handling it is very pos- 
sible, but the analytical data and cost af- 
ford every reason for testing the value as 
@ source of alcohol. 
Potatoes—Following is the average com- 
position of Maine potatoes, as determined 
a few years ago in the Bureau of Chem- 
istry: 
Per cent. 
Water onic cenccecere cee secensecen cenceeeteeeee 77.0 
DN) ere 9 
PLOC@ID oie ele eeeeen eee cme ceeceeneeeerenenceen 2.2 
I hp 0 6) -) wt 
FRAC oa cecccce cecece cca censeeenancuecnresnuccscesenserenees 1 
StArGh ooo cseece seco ececneeneecoueee cosnaens 18.3 
Sugars, etc., by difference................ 8 
sk 0): | 100.0 
Samples analyzed more recently in con- 
nection with the work of the experimental 
distillery were found to contain about 15 
per cent of starch and 0.4 per cent of 
sugars. Liquid wastes from starch fac- 
tories in Maine were also examined, but 
did not contain sufficient fermentable ma- 
terial to be of value for alcohol produc- 
tion. 
The method of working potatoes is dis- 
cussed at length in Farmers’ Bulletin 410. 
For every per cent of starch contained 
in potatoes they should yield about 1.6 gal- 
lons of alcohol per ton. If the tubers con- 
tain 16 per cent of starch, a ton should 
Yield over 25 gallons of alcohol; and if 
they can be delivered at the distillery for 
$68 per ton, a fair price for culls in potato- 
growing regions, the raw material for a 
gallon of alcohol will cost about 20 cents. 
In Germany the potato is almost the 
only material used as a source of indus- 
trial alcohol, not only because it offers a 
cheap raw material, but because it is 
highly advantageous from an agricultural 
point of view. It undoubtedly will be 
Similarly utilized in this country in the 
future. 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
Sweet potatoes—The following average 
data are based on work done at the South 
Carolina station (1) and may be consid. 
ered aS representing sweet potatoes of 
good quality: 
Per cent, 
Water ........ ee. 66.0 
CS) | ee 1.0 
Protein ....ccceeeeeeeee cee ee ee cee 1.5 
|S) 6) -5 1.3 
BAC oeeeeceeeeeeceweeecceeecceccenecneveccecneeseeneee 5 
SUSALS oeccecececeeece - cee e ceneceees te tenes eee 5.5 
STALCH oo.ceeeceeeeeeeceeeee ee cee eeem ence caseeeees 21.8 
Undetermined material 2.4 
Total ..... le ee 100.0 
These roots are seen to contain about 
27 per cent of fermentable substances, of 
which approximately one-fifth is sugars. 
In storage there is a decrease in the starch 
percentage and a corresponding increase 
in that of sugar. 
Preliminary experiments conducted at 
the Bureau of Chemistry indicate that the 
sweet potato can be mashed in about the 
same way as the common potato. Un- 
doubtedly there will be some slight de- 
struction of sugar on heating under pres- 
sure, but it ought not be such as to cause 
a serious loss. It does not appear that 
the somewhat fibrous character of the 
root interferes with steaming it in an 
apparatus built for potatoes. 
A ton of sweet potatoes, containing 
about 27 per cent of fermentable sub- 
stances and costing $8, should yield ap- 
proximately 88 gallons of alcohol at a 
cost of about 21 cents a gallon for raw 
material. 
Manufacture of Alcohol 
Historical Note 
Although there are processes by which 
alcohol may be made synthetically in the 
laboratory, they are too complicated and 
expensive to have any practical manu- 
facturing value. Therefore the method 
which has been used for many centuries, 
namely, the distillation of fermented- 
sugar solutions, is still employed in al- 
cohol production. This manufacturing 
process is very ancient, having been used 
probably as early as 800 B. C. It seems 
for many centuries to have been employed 
(1) South Carolina Bulletin 186, 1908. p. 11. 
