2 BULLETIN 983, U. S. DEPARTMENT OE AGRICULTURE. 



season and from year to year, before the war the average cost of the 

 materials for making grain alcohol, fuel excluded, was about 27^ 

 cents a 188-proof gallon. Manufacturing costs, including coal, 

 interest, repairs, depreciation, taxes, labor, etc., range from 10 to 17 

 cents a gallon of 188-proof alcohol, depending upon the location and 

 efficiency of the plant. 



One gallon of molasses yields from 0.45 to 0.48 of a gallon of 188- 

 proof spirit. The price of molasses before the war averaged from 

 5 to 7.5 cents a gallon, and, therefore, the approximate cost of raw 

 material in a gallon of molasses spirit was from 10 to 15 cents. The 

 cost of production of molasses spirit is slightly less than that of 

 grain spirit, but in either case the cost of raw material is compara- 

 tively high. 



One ton of dry sawdust or other wood waste (or its equivalent on 

 an air-dry or green basis) will yield from 12 to 20 gallons of 188-proof 

 spirit. The disposal of this waste in the vicinity of a sawmill or 

 other large woodworking plant is specifically an item of loss, because 

 most sawmills produce waste in excess of their own power require- 

 ments. Sometimes the waste is not worth more than 30 to 50 cents 

 a ton, and this makes the cost of raw material in a gallon of ethyl 

 alcohol from sawdust about 2 cents. This includes also the fuel 

 charge, for the residue after conversion and extraction is available 

 for fuel, whereas in grain distilleries about 7 tons of coal and in 

 molasses distilleries about 4 tons are required in producing 1,000 

 gallons of 188-proof spirit. 



If the manufacturing cost of producing ethyl alcohol from wood 

 can be reduced to the same figure or nearly the same as that for 

 making it from grain or molasses, there will be a large margin in 

 favor of producing the alcohol from wood waste. Of course, with 

 a yield of 12 to 20 gallons from a ton of wood and 80 gallons from a 

 ton of corn, the amount of material handled in certain parts of the 

 plant producing alcohol from wood will be four or five times as great as 

 in a grain distillery of equal producing capacity, and this will require 

 a larger-sized plant and an increased operating cost. 



In recent years the production of ethyl alcohol from sawdust has 

 received a great deal of attention, and a large amount of money has 

 been spent in the technical development of the process. A number of 

 plants have been built in this country, but only two have been con- 

 sidered commercial successes. 



Because of the importance to the lumber industry of the problem 

 of waste disposal, and because this process is practically the only one 

 applicable to the disposal of wood waste, the Forest Service has inves- 

 tigated the different processes and, so far as possible, the plants that 

 have been built, in order to learn the causes of former failures and 

 to aid in the commercial development and success of the processes. 



