Mr. Henry en Ferments and Fermentation. 285 



clic acid, appearing to be fully adequate to the 

 purpofe, and being, I believe, fufficient for 

 impregnating the v/ort, without any other con- 

 trivance. This difcovery therefore may, per- 

 haps, be of no fmall utility in public breweries, 

 and I would recommend it to the attention of 

 perfons concerned in the brewing trade. 



Let us now proceed to dcfcribe the circum- 

 ftances neceflary to, and the phsenomena attend- 

 ing fermentation, as defcribed by chemical 

 writers ; and then endeavour to form fome theory 

 which may account for them. 



Sugar, the juices of ripe fruit, and malt are 

 all more or lefs difpofed to run into fermen- 

 tation. But before this can take place, it is 

 neceflary they fhould be diluted with water, 

 fo as to bring them to a liquid ftate. A due 

 degree of heat is alfo requifite, as the fermen- 

 tation fucceeds beft when the temperature varies 

 from 70 to 80 degrees. 



When the fermentation takes place, a briik 

 inteftine motion is obfervable in the liquor; 

 it becomes turbid, fome fjEculse fubfide, while 

 a frothy fcum arifes to the furface. A hifTing 

 noife is obferved, and a quantity of gas is dif- 

 charged, which has been proved to be fixed 

 air. The liquor acquires a vinous fmell and 

 tafle J and, from being heavier, becomes fpecifi- 

 cally lighter, than water. During the progrefs 

 of the proccfs, the temperature of the liquor 



IS 



