Proceedings of the British Association. 105 



of malt, weighing 125 lb. 3 oz., were wetted with 30 gallons of water at 

 167°, and the mixture being well agitated, the mash was left covered up 

 at a temperature of 140° during three hours, when 19 gallons of fine 

 worts were drawn off at the specific gravity of 1.0902, or 90.2 degrees. 

 Twenty gallons more water at 167° were then added to the residuum, 

 which afforded after two hours 28 gallons of wort at the gravity of 1.036 ; 

 12 gallons of water at 167° were now poured on, which yielded after 

 other two hours 15 gallons at the gravity 1.0185. Forty gallons of fine 

 worts at 1.058 gravity, and 68° temperature, were collected in the even- 

 ing of the same day, and let into the tun with 5 per cent, of yeast. 

 The attenuation amounted in six days to 54 degrees. The third wort of 

 this brewing, amounting to 15 gallons, being very feeble, was mixed with 

 7 gallons of the first and second worts, put into a copper, and concentra- 

 ted by boiling to 11 gallons, which had a gravity of 1.058 at 60° F. 

 They were separately fermented with five per cent, of yeast, and suffer- 

 ed an attenuation of 48l degrees. The produce of spirit from both, 

 indicated by the attenuation was 5.36 gallons ; the produce in low wines 

 was actually 5.52, and that in spirits and feints was 5.33, being a perfect 

 accordance with the Excise tables. 



The next experiments were made with a view of determining at what 

 elevation of temperature the activity or efficiency of yeast would be 

 paralyzed, and how far the attenuation of worts could be pushed within six 

 hours, which is the time limited by law for worts to be collected into 

 the tun, from the time of beginning to run from the coolers. When 

 worts of the gravity 1.0898 were set at 96° Fahr., with 5 per cent, of 

 yeast, they attenuated 26.9° in six hours ; worts of 1.0535 gravity set at 

 110° with 5 per cent, of yeast, attenuated 16o in about 5 hours; but 

 when worts of 1.0533 were set, as above, at 120°, they neither fermented 

 then, nor when allowed to cool ; showing that the activity of the yeast 

 was destroyed. When fresh yeast was now added to the last portion of 

 worts, the attenuation became 5.8° in 2 hours, and 28.4° in 3 days ; 

 showing that the saccharine matter of the worts still retained its fermen- 

 tative faculty. Malt worts being brewed as above specified, were set in 

 the tun, one portion at a temperature of 70°, with a gravity of 1.0939, 

 and 5 per cent, of yeast, which attenuated 66° in 3 days ; other two por- 

 tions of the same gravity were set at 120°, with about 10 per cent, of 

 yeast, which underwent no fermentative change or attenuation in 6 

 hours, all the yeast having fallen to the bottom of the tuns. When these 

 two samples of worts were allowed, however, to cool to from 74° to 72°, 

 fermentation commenced, and produced in two days an attenuation of 

 about 79°. It would appear, from these last two experiments, that 

 yeast to the amount of 5 per cent, is so powerfully affected by strong- 

 worts heated to 120°, as to have its fermentative energy destroyed ; but 

 that when yeast is added to the amount of 10 per cent., the 5 parts of 

 excess are not permanently decomposed, but have their activity merely 

 suspended till the saccharine liquid falls to a temperature compatible 



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