CHAPTER IX* 

 THE MANUFACTURE OF OTHER FERMENTED PRODUCTS 



Preparation and Conservation of Food Material 



Compressed Yeast. — ^Yeast in the form of a thick paste is produced 

 in large quantities for the use of bakers. It should be white, vigorous 

 and rich in nitrogen. ' 



In the Vienna method, a saccharine solution is made in a manner 

 similar to that used in distilling, by saccharification with malt and acidir 

 fication by lactic bacteria. Many grains, principally barley — malt, 

 rye and corn, are used. A mixture of the three gives a solution which 

 has the required concentration and the proper degree of viscosity to 

 facilitate the separation of the yeast. 



In the method by aeration a sweet wort is made from green malt, 

 that is, sprouted barley. The malt is crushed, mixed with water and 

 "mashed" for several hours at about 60° to saccharify the starch by 

 diastatic action. The mash is then cooled to 50° and inoculated with 

 a culture of lactic acid bacteria. When the liquid is suflSciently acidified 

 by the action of the bacteria it is sterilized by heating to boiling. It is 

 then filtered and cooled. This sweet wort should contain about 14 

 pet cent of total solids. 



The cooled wort is inoculated or "pitched" with a large starter of 

 veast and thoroughly aerated during fermentation by means of com- 

 pressed air. Yeast growth and fermentation are cornplete in twenty- 

 four hours or less. The yeast is separated from most of the liquid 

 by means of a centrifugal machine and is then made drier by means 

 of a filter press. It then forms a paste that can be molded into any 

 desired shape or size. 



The liquid or "wash" separated from the yeast is distilled and the 

 alcohol used for the manufacture of distilled vinegar. 



A small number of lactic acid bacteria in the finished product is 



* Prepared by F. T. Bioletti. 



SSI 



