20 



BULLETIN 983, U. S. DEPARTMENT OF AGRICULTURE. 



periods in the sugar solution, and, therefore, a three or four months' 

 stock can usually be made up at one time. 



When a series of fermentations was ready to be run, the small yeast 

 sample in either the 50 c. c. Florence flask or the side-neck Freuden- 

 reich flask was added to 50 c. c. of 12° Brix sterile molasses, which was 

 kept at 30° C. ±0.5° C. 35 for about 24 hours. Of this solution 10 c. c. 

 was then added to 250 c. c. of 18° Brix molasses after about 18 hours 

 at 30° C. Of this sample 50 c. c. was transformed to 1,500 c. c. of 18° 

 Brix molasses, which was allowed to work off to about 12° Brix in 15 

 to 18 hours, when it was ready for use as the starting yeast. 



Meanwhile a sprout mash was made up of 8.5 grams of malt 

 sprouts and 2.5 grams of ammonium sulphate, boiled for 15 minutes 

 in 250 c. c. of the wood-sugar solution to be fermented. This was 

 cooled to 30° C. } and 75 c. c. of the starting yeast (in 12° Brix molas- 

 ses) was added. After 6 hours the mash was washed into a 20-liter 

 bottle (a half carboy) with 100 c. c. of the wood-sugar solution. The 

 latter varied in concentration from about 10° to 13.5° Brix, the 

 average being 12° to 12.5°. The exact concentrations for each fer- 

 mentation are shown on the fermentation sheet. After 3 hours 

 100 c. c. of wood-sugar solution was added; after 3 hours, 200 c. c; 

 after 3 hours, 200 c. c. ; after 2.5 hours, 400 c. c. ; and each hour there- 

 after, 400 c. c, until a final volume of 2 gallons (7,570 c. c.) was made 

 up. The general plan of starting and filling the fermenters is shown 

 in the following table : 



Fermentation No. 2. Cooks 29, 33, 34, 35, 36, 37, 38, and 39. Starting yeast, 12° Brix. 



Sept. 24 



Sept. 25 



Volume 

 added. 



30 a.m. 1 

 30 p.m.. 

 30 p.m. 

 30 p.m. 

 30 a. m . 

 00 a.m. 

 00 a.m. 

 00 a.m. 

 00a.m. 

 00a.m. 

 00 a.m. 



C.c: 



250 

 100 

 100 

 200 

 200 

 400 

 400 

 400 

 400 

 400 

 400 



Total 

 volume. 



C.c. 



250 



350 



450 



650 



850 



1,250 



1,650 



2,050 



2,450 



2,850 



3, 250 



Sept. 25 



Volume ; Total 

 added, i volume. 



9.00 a.m. 

 10.00 a. m 

 11.00 a. m 

 12.00 m... 

 1.00 p.m. 

 2.00 p.m. 

 3.00 p.m. 

 4.00 p.m. 

 5.00 p.m. 

 6.00 p. m. 

 7.00 p.m. 



C.c. 

 400 

 400 

 400 

 400 

 400 

 400 

 400 

 400 

 400 

 400 

 320 



C.c. 

 3,650 

 4,050 

 4, 450 

 4,850 

 5,250 

 5,650 

 6,050 

 6,450 

 6,850 

 7,250 

 7,570 



1 Time sprout mash was set. 



The above scheme was intended to duplicate as nearly as possible 

 the times at which the different amounts of the solutions would be 

 added from the different yeast tubs to the fermenters on a commercial 

 scale. The first steps up to 3 a. m. are acclimating and propagating 

 the yeast in the yeast tubs, and the final transfer into the fermenters 

 is made at 3 a. m. From then on it takes from 12 to 18 hours in 



35 All fermentations were made in a fermentation room, the temperature of which was kept constant at 

 30° C±0.5° C,and which could be sterilized and kept in a clean condition. 



