The attenuation should in no case proceed at the rate of
less than one pound every twenty-four hours ; so long as
the attenuation proceeds at above one pound, there is no
danger.
The period at which ales above the gravity of 23 should
be cleansed into casks or skimmed, is when the attenuatioa
has gone down about two-thirds, or when the heat has
reached 74°, w^hether the attenuation has gone down two-»
thirds or not.
The great advantage of completing the fermentation in
the squares, is that you insure your attenuation being con-
ducted to nearly any point required, whilst by finishing the
fermentation in casks, it is impossible, you cease in fact, to
have any control, hence great irregularity in (he attenuation
and consequently flavour and condition.
Let a brewer's experience or scientific knowledge
be ever so great, not one yet has been enabled to
ensure a perfect uniformity in all his fermmitatians



201

.There are many causes operating to produce this irregu-
larity, — first, the presence of sulphur in all ^ops^ and
more or less in malt. Second, the high temperature
at which fermentations are generally conducted. Third,
the imprudent arrangement of the plant, rendering perfect
cleanliness impossible, in this I refer particularly to the
quantity of metal pipe, and wort pumps. Fourth, electri-
city. Fifth, the want of a uniform character, quality, a,nd
color in malt.
A perfect fermentation has several distinct changes, with
the rise of the carbonic acid gas you have a pungent aroma,
and vinous to the smell.
