STUDIES ON FEKMENTATION. 9 



This is not, however, the only reason for the use of the term 

 '^ high fermentation." We have just seen that the fermenting 

 casks were so arranged that most of the yeast produced during 

 the process of fermentation would rise to the upper part 

 of the casks and work out of the bung-holes. In this 

 practical fact we have the actual origin of the expressions 

 '■^ high fermentation^^ and ^^ high beer,'" which are used to 

 distinguish this peculiar fermentation and the quality of beer 

 derived from it. 



As we have alread)^ observed, all beer was formerly produced 

 by this mode of fermentation, which even at the present time 

 is still practised in the breweries of Great Britain, where beer 

 fermented at a low temperature is absolutely unknown. 



" Low fermentation " is a slow process, eflfected at a low 

 temperature, during which the yeast sinks to the bottom of the 

 vats or casks. The wort, after cooling, is run into open wooden 

 vats. In cooling, the wort is brought to as low a temperature 

 as 8° 0. (47° F.), or even 6° C. (43° F.), at which point it is 

 maintained by cones or cylinders (styled nageurs, i.e., floats, by 

 the French) floating in the fermenting vats. These floats may 

 be filled with ice if the outside temperature requires it, as is 

 invariably the case in summer. 



pitched with 600 lbs. of fairly solid yeast. In forty-six hours the attenu- 

 ation was considered sufficient, and the beer, which from an initial heat 

 of o8-r F. or 14-5° C, had risen to 72° F. or 22-2° C, was cleansed 

 to working casks. The large vats in which the fermentation is started 

 may be considered as equivalent to the cuves guilloires of French 

 breweries, the casks in which it is completed and the yeast thrown off 

 representing their 7 5 -litre vessels, improperly called quarts. Notwith- 

 standing the enormous English beer manufacture, and although the 

 fermenting vat, as in making porter, for instance, sometimes attains the 

 capacity of 2,000 to 3,000 litres (400 to 600 gallons), the casks into 

 which it is run are never larger than 15 to 20 hectolitres (300 to 400 

 gallons); and even at Burton, in the celebrated breweries of Allsopp 

 and Bass, the pale ale is finished in casks of a capacity less than 

 10 hectolitres, and yet the average turn-out of these immense works 

 reaches 3,000 to 4,000 hectolitres (60,000 to 80,000 gallons) of beer 

 per day. 



