FERMENTED DRINKS II3 



and (3) to get a fresh supply of yeast. After this the 

 trouble ought to disappear. It is also important to re- 

 member that the sliminess occurs only if the bread is 

 kept warm, and hence chiefly in the summer. If the 

 bread is cooled at once and kept in a cool place xmtil it is 

 eaten, the trouble is not likely to manifest itself even 

 though the slimy bacteria are present. The bread is 

 wholesome enough even though slimy. 



The Utilization of both Alcohol and Carbon 

 Dioxide 



In the production of beers, porters, ales, etc., both of the 

 products of fermentation are commonly utiUzed. The gen- 

 eral character and effect of beer are due partly to the 

 alcohol present and partly to the presence of a quantity of 

 the carbon dioxide, which gives to the beer its sparkle. 

 In the manufacture of such a product the fermentable ma- 

 terial, usually some form of grain, is inoculated with a large 

 quantity of a vigorous yeast, a species being chosen that 

 has been found by experience to produce the desired 

 results. A fermentation starts up which progresses rap- 

 idly if the temperature is kept warm, as it is in the manu- 

 facture of common beer. The process lasts from a few days 

 to several weeks according to temperature and the kind of 

 beer being made. During this fermentation alcohol accumu- 

 lates in the liquid, and the carbon dioxide gas escapes into 

 the air, forming a froth in the fermenting vat. The yeast 

 increases in amount, and dther collects on the surface or 

 sinks to the bottom. Most of the yeast is then removed, 

 and the liquid stored in casks or bottles. Here the fermen- 



