32 



BULLETIN 983, U. S. DEPARTMENT OF AGRICULTUEE. 



Another series of experiments was made on autoclaving the neu- 

 tralized juice before and after fermentation. The results of these 

 experiments are given in the following tables. It is of particular 

 interest to note here that a greater sugar decomposition occurred 

 in the autoclave of both the neutral juice and the beer when no sul- 

 phuric acid was added than when sulphuric acid was added before 

 autoclaving. The volatile-acid figures, although somewhat erratic, 

 show a decided tendency toward an increase of volatile acid, although 

 here we have a mixture of conditions in which, undoubtedly, a 

 number of secondary reactions take place, and some of the combined 

 acids that are present either as calcium salts or organic combinations 

 are liberated during the autoclave process. 



Autoclave cooks on fermented and unfermented wood-sugar extracts. 



No. 



Reducing 



sugars oer 



lOOc.'c. 



Acetic 

 acid per 

 100 c. c. 



Formic 

 acid per 

 100 c. c. 



Sulphuric 

 acid per 

 100 c. c. 



Total 



volatile 



acid. 



Neutral juice: 



74-6(1)... 



74-6(2)... 



74-6(3)... 



74-6(4)... 

 Beer: 



74-7(1)... 



74-7(2)... 



74-7(3)... 



74-7(4)... 

 Neutral juice: 



73-6(1)... 



73-6(2)... 



73-6(3)... 



73-6 < 4)... 

 Beer: 



73-7(1)... 



73-7(2)... 



73-7(3)... 



73-7(4)... 



39.72 

 18.148 

 31.824 

 36.08 



17.99 



7.70 



12.29 



13.11 



41.29 



14.24 

 22.04 

 29.03 



41.624 

 12.94 

 20.75 

 19.01 



0.248 

 .356 

 .263 

 .333 



.387 



.480 



1.208 



.341 



.713 



.527 



1.038 



1.418 

 1.356 

 1.286 



0.380 

 .582 

 .540 

 .338 



.665 

 .754 

 .095 

 .671 



.184 

 .404 

 .238 

 .439 



.392 

 .540 

 .410 

 .475 



0.628 

 .938 



.803 

 .671 



1.052 

 1.234 

 1.303 

 1.012 



.897 

 1.287 

 1.116 



1.430 

 1.95S 

 1.866 

 1.761 



(1) original; (2) original autoclaved, 112 pounds for 15 min utes: (3) original plus 0.5 per cent of sulphuric 

 acid autoclaved, 112 pounds for 15 minutes: (4) original plus 0.5 per cent of sulphuric acid autoclaved, 112 

 pounds for 15 minutes. 



The experimental procedure covering the previous series of auto- 

 clave cooks on fermented and unfermented extracts, ' also sugar 

 solutions in both water and sulphuric acid, was carried on as follows : 

 Fifty Cubic centimeters of the solution was put into a pear-shaped, 

 porcelain-stoppered, rubber-gasketed pressure flask of glass, which 

 was put into an autoclave, the flask being surrounded by water.. 

 The autoclave was gas heated, and steam pressure was turned into 

 the autoclave so fast as to make the autoclave cooks comparable 

 with the digester cooks. As the flasks were stoppered, none of the 

 volatile acids could escape, and they were determined along with 

 the sugars in the solutions after they were cooked in the autoclave. 



Comparing these yields with those shown above for series II, it is 

 seen that the yields were higher at 6 and 9 atmospheres, no doubt on 

 account of different amounts of water present. For all technical 



