104 Proceedings of the British Association. 



two hours more, twenty additional gallons of water at the temperature of 

 200° were introduced, when the mash was well stirred, and then covered 

 up for two hours, at which period 23 gallons of fine worts, of specific 

 gravity 1.242, were drawn off. An hour afterwards 12 gallons of water 

 at 200° were added to the residual grains, and in an hour and a half 1 1 

 gallons of wort, of the density 1.033, were obtained. Next morning the 

 several worts were collected in a new mash tun. They consisted of 48 

 gallons at the temperature 80°, and of a specific gravity 2.0465, when 

 reduced to 60°. Being set at 80°, fermentation soon commenced ; in two 

 days the specific gravity had fallen to 1.0317 ; in three days to 1.018; in 

 four days to 1.013; and in five days to 1.012; the temperature having 

 at last fallen to 78° F. The total attenuation was therefore 34! degrees, 

 indicating the production of 3.31 gallons of proof spirit ; while the pro- 

 duce by distillation in Ioav wines was 3.22 ; and by rectification in spirits 

 and feints it was 3.05. The next experiment was commenced on the 

 12th of October, upon a similar mixture of corn to the preceding. 48 

 gallons of worts of 1.043 specific gravity were set at 82 in the tun, which 

 next day was attenuated to 1.0418; in two days to 1.0202 ; in three days 

 to 1.0125; and in five days to 1.0105 : constituting in the whole an atten- 

 uation of 32| degrees, which indicates the production of 3.12 gallons of 

 proof spirits ; while the produce of the first distillation was 2.93 in low 

 wines ; and that of the second in feints and spirits was 2.66. In these 

 experiments, the wash when fermenting most actively, seemed to simmer 

 and boil on the surface, with the emission of a hissing noise, and the 

 copious evolution of carbonic acid gas. They prove beyond all doubt, 

 that much alcohol may be generated in grain worts, without the 

 addition of yeast, and that also at an early period ; but the fermentation 

 is never so active as with yeast, nor does it continue so long, or proceed 

 to nearly the same degree of attenuation. I was never satisfied with 

 the construction of the mash tun used in these experiments, and had ac- 

 cordingly suggested another form, by which the mash mixture could be 

 maintained at the proper temperature during the mashing period. It is 

 known to chemists, that the diastase of malt is the true saccharifying 

 ferment which converts the fecula or starch of barley and other corn in- 

 to sugar ; but it acts beneficially only between the temperatures of 145° 

 and 168° F.* When the temperature falls below the former number 

 saccharification languishes, and when it rises much above the latter it is 

 entirely checked. The new mash tun was made of sheet zinc, somewhat 

 wider at bottom than top ; it was placed in a wooded tun, so much larger, 

 as to leave an interstitial space between the two of a couple of inches at 

 the sides and bottom. Through this space a current of water at 160° 

 was made to circulate slowly during the mashing period. Three bushels 



* M. Raspail's observations upon diastase are entirely erroneous; and cannot be 

 allowed to invalidate the facts adduced by Payen, Persoz, and Guerin Varry. In 

 fact, were Raspail correct, wheat flour boiled with water should immediately form 

 sugar. 



