178 FERMENTING THE WORT. 



longs the fermentation, or rather causes it to recom- 

 mence. 



426. Whilst the fermentation of the wort is pro- 

 ceeding, it gradually becomes clearer; the ferment 

 added, as well as that which is generated in the wort 

 (for all the azotized matter present is soon brought 

 into the same condition of active fermentation), is 

 gradually separated; meanwhile the sugar is decom- 

 posed, spirit is formed, carbonic acid given off, and a 

 considerable amount of heat is generated. Where 

 the quantity of wort is large, this rise in temperature 

 amounts to ten or fifteen degrees. 



427. In making ale and beer, it is the object of 

 the brewer to leave a portion of the sugar in the liquid, 

 he therefore removes the yeast so as to put a stop to 

 further fermentation; but in brewing porter he does 

 not remove the ferment so soon, but allows the fer- 

 mentation of the wort to continue for a longer time. 

 It is sometimes found convenient to add a small 

 quantity of sugar to the wort. 



428. After the first fermentation is finished and 

 the yeast removed, the liquor is racked or drawn off 

 into casks, when it undergoes a second fermentation 

 far more slow and protracted than the first. This is 

 termed cleansing, and, whilst it goes on, a consider- 

 able quantity of mucilage, spent ferment, and other 

 impurities subsides, constituting the lees or dregs. 

 When this second fermentation is complete, the liquor 

 is drawn off into casks, the bungholes of which are 

 then well closed. 



