96

FERMENTATION.

the production of 302 gallons of proof spirits ; while the produce of the first disti ^tion was 2-93 in low wines, and that of the second in feints and spirits was S'6o- ■[

these experiments the wash, when fermenting most actively, seemed to simmer an ? ca f.on the surface, with the emission of a hissing noise, and the copious evolution oi ‘- nbonic acid gas. They prove beyond all doubt that much alcohol may be generate ^grain worts without the addition of yeast, and that, also, at an early period; bu ,fermentation is never so active as with yeast, nor does it continue so long, or P r ° ^ orlto nearly the same degree of attenuation. I was never satisfied with the eonstruc^^.of the mash tun used in these experiments, and had accordingly suggested an ^ jeform, by which the mash mixture could be maintained sit the proper temp e ! a t j,eduring the mashing period. It is known to chemists that the diastase of malt i3 0 ib&true saccharifying ferment which converts the fecula, or starch of barley and a ndcorn, into sugar ; but it acts beneficially only between the temperatures of j a jj-168° F. When the temperature falls below the former number, saccharificat 1 ® ^yguishes ; and when it rises much above the latter, it is entirely checked. 1“.^ yy a smash tun was made of sheet zinc, somewhat wider at bottom than top; ' t heplaced in a wooden tun, so much larger as to leave an interstitial space I ,et '' e urr ei' ttwo of a couple of inches at the sides and bottom. Through this space aof water at 160° was made to circulate slowly during the mashing period. ^ jgy°,bushels of malt, weighing 125 lbs. 3 oz., were wetted with 30 gallons of water a tu reand the mixture being well agitated, the mash was left covered up at a at the f pe:of 140° during three hours, when 19 gallons of fine worts wore drawn oil a* a( jdedcific gravity of T0902 or 90-2°. Twenty gallons more water at 167° were th e ^yjtyto the residuum, which afforded after two hours 28 gallons of wort at the = 0 (jier1*036; 12 gallons of water at 167° were now poured on, which yielded a ^ j-05®two hours 15 gallons at the gravity T0185. Forty gallons of fine worts aIlt t letgravity and 68° temperature were collected in the evening of the same <j a I> Sh-into the tun with 5 per cent, of yeast. The attenuation amounted in six d a J mi* .The third w r ort of this brewing, amounting to 15 gallons, being very feeble, W

with 7 gallons of the first and second worts, put into a copper, and concen aI ateWboiling to 11 gallons, which had a gravity 1:058 at 60° F. They were ^ ^ o( j U cefermented with 5 per cent, of yeast, and suffered an attenuation of 48J°. jn 1 o'*

of spirit from both indicated by the attenuation was 5-36 gallons; the P r0 aC comwines was actually 5*52, and that in spirits and feints was 5*33, being a perance with the Excise tables.

ration

far

of

the

LbC Willi 11LC JjAvJQC lUUlvo* ip.»

The next experiments were made with a view of determining at what e joitemperature the activity or efficiency of yeast would be paralysed, and n ^ped Wattenuation of worts could be pushed within six hours, which is the tIin f r oiu Wlaw for worts to be collected into the tun, from the time of beginning to cen t. °coolers. When worts of the gravity 1-0898 were set at 96° Fahr., with I jj qo w)yeast, they attenuated 26-9° in 6 hours; worts of 1-0535 gravity se j.Q533'"’ c5 per cent, of yeast, attenuated 16° in about 5 hours; but when worts o . sh 0 ' taset, as above, at 120°, they neither fermented then, nor when allowed ^ a dde aing that the activity of the yeast was destroyed. When fresh yeast was o jn 3 d®T |the last portion of worts, the attenuation became 5-8 in 2 hours, and jj ve fa ca •showing that the saccharine matter of the worts still retained its * erine rt j 0 n at a te te iMalt worts, being brewed as above specified, were set in the tun, oae Wattend* yperature of 70°, with a gravity of 1-0939, and 5 per cent, of 7 ea j’nno with a ' , ° U u rS'66° in 3 days; other two portions of the same gravity were set at 1 . Qn jn 6 h° 0 {per cent, of yeast, which underwent no fermentative change or atten q s amP^ e ce i,all the yeast having fallen to the bottom of the tuns. When tliea n conrn iea , s eworts were allowed, however, to cool to from 74° to 72 3 , ^' eTm . e J 1 „ ve ai, fro® 0 -, -tedand produced in two days an attenuation of about 79°. It woul ’ ver fully a *7 f],atlast two experiments, that yeast to the amount of 5 per cent, is s0 P stro yed; bu , )C rby strong worts heated to 120° as to have its fermentative energy egs a re n °. a jjn®when yeast is added to the amount of 10 per cent., the 5 parts o ^ ^ sa® cmanently decomposed, but have their activity merely suspenae according an s*liquid falls to a temperature compatible with fermentation. a itog et ' ier °- nC h ' 11

observations, when viewed in a good acromatic microscope, ‘ ar t of ° n V. th®)'

lucent spherical and spheroidal particles, each of about the oO a little wa ’ p ro iudiameter. When the beer in which they float is washed away ' ,. ain jned dir eC ■ p theare seen to be colorless; their yellowish tint, when they are jnfus'on^.jiJcr

the fermenting square or round of a porter brewery, being du 0 f partid eS ^, lie re-

brown malt. The yeast of a square newly set seems to co gjjerable- t tl> e

than those of older yeast, but the difference of size is n ° f0 sh b eel>searches of Schulze, Cagniard de la Tour, and Schwann , P es whichvinous fermentation, and the putrefaction of animal matter , p