go 
fame equable temperature for a fuf- 
ficient time. 
“0A box of this kind, in which the 
following experiments were made, 
was placed on a drefler in my 
kitchen, more than eighteen feet 
from the kitchen-fire, but againi a 
thin wall, which divides the kitchen 
from the fervants hall, juft behind 
the fire-place of that room; and 
the open fide of the box turned to 
the heated wall, the veffels them- 
felves uncovered. If you recollect 
the trouble you fo obligingly took 
in heating your office, you will 
think this method, fince difcovered, 
of performing the fame experiment, 
of confiderable utility. 
Experiment 1ft.—Three veffels 
were fet at the fame time in the 
warm box, containing a quart of 
liquor each, and of equal ftrength 
with refpect to malt: one was a 
decostion without hops, another with 
hops, the other a fimple infufion of 
malt: in about twenty-four hours 
the hopped decoction produced a 
fine head of yeait; the other de- 
coction fermented as. well, but was 
twenty-four hours later; the fimple 
infufion was near thirty-fix hours 
Jater, and the yeaft appeared dark 
and ill-coloured, fo that my hcufe- 
keeper thought it fpoiled ; but this 
bad appearance was merely owing 
to its not having been boiled and 
cleared, for it made very light 
break/aft rolls. 
This experiment, you will per- 
ceive, was made to try whether 
hops (as my fervant imagined) were 
neceflary; and it certainly proves 
that they accelerate the fermenta- 
tion; but it. proves alfo, that nei- 
ther hops not’ boiling are efiential 
to-the procefs. 
xperiment 
- 
f 24.— Four vefiels 
from a* common brewing ef ale 
g 
fy 
ANNUAL OREGISITER, 11790: 
were placed in a box of longer di- 
menfions ; one contained two quarts $ 
a fecond, one; a third, a pint; a 
fourth, half a pint: they all fhewed 
figns’ of fermentation at the fame 
time, viz. in about twenty-four 
hours; but that in the mug or pot 
holding a pint appeared the ftrong- 
eft, which my fervant thought was 
owing to the fmaller diameter of 
the veflel, which was fmaller in pro- 
portion to the half-pint; but as it 
ftood more centrally to the heat of 
the fire behind, I am perfuaded the 
excefs of fermentation proceeded 
from that caufe. . This proves that 
the quantity you begin the procefs 
with is not very material: though 
two quarts feem to be moft conve-: 
nient for the purpofe of baking. 
Experiment 3d, Was inftitated 
merely to find whether an addition 
of {ugar would accelerate the fer- 
mentation; for which purpofe, two: 
quarts of hopped liquor were tried 
in feparate veflels, a quart in each :/ 
and the refult was, that the decoc- 
tion, in which two large fpoonfuls 
of coarfe fugar were ftirred in, did 
not ferment in the ‘leaft, though: 
continued in the warm box five days 
and nights; the other fermented in- 
about thirty-fix hours. The reafon 
of this later fermentation than of 
that in the former experiments 
was, that the liquor ufed was from’ 
Hence: 
a brewing of fmall-beer. 
we may conclude, that a decottion 
of the ftrength of ale; if not of 
itrong beer, is the beft to begin 
with. 
Account of Experiments on the Gene- 
ration of Yeaft, made under the In- 
Spettion of the Committee of Che- 
mife-y, in the Month of November’ 
1789. 
FOUR 
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