Studies on Fermentation: The diseases of beer, their causes, and the means of preventing themPasteur, Louis
Science
Studies on Fermentation: The diseases of beer, their causes, and the means of preventing them
Pasteur, Louis
Beer; Fermentation
“If we use a perfectly filtered wort, containing no granulations, and
prepared at a temperature between 60° C. and 70° C. (140° F. and 160°
F.), there will first of all appear a multitude of fine granules that
will develop into active bacteria, which, losing the faculty of motion,
will constitute lactic ferment, as I have repeatedly pointed out. A few
days after the appearance of the first granules, we shall perceive
others rather larger in size and isolated. These will increase in size,
and, in the course of time, assume the form of little globuloid, or
elliptic cells; they will not commence to bud before they have attained
a comparatively large size, approaching that of ordinary yeast,
consequently, there will be a considerable interval of time, during
which the young cells will present no buds, especially if we work at a
low temperature, as from 20° C. to 35° C. (68° F. to 95° F.)
“As for the transformation of the spores of _penicillium_ into alcoholic
ferment, the possibility of which M. Pasteur also denies, I have very
often obtained it by using liquids, such as boiled wort and sugared
barley water, which had stood for a month or six weeks without setting
up an alcoholic fermentation. These liquids, sown with spores of
different forms of _penicillium_, chosen when young and in full growth,
fermented after a varying number of days, even at a temperature of 12°
C. (54° F.), the condition of fermentation being that the flasks were
closed with very elastic corks, which had been boiled for a quarter or
half an hour; these corks, as I have already pointed out, it is best to
keep for a month after the boiling, to make sure, by drying them
thoroughly again, of destroying any _mycelia_ adhering to them. It is
necessary to keep the flasks stoppered that the corks may be always
moist, and it is also advisable to shake the flasks once or twice a day,
to secure the submersion of the spores. If these conditions are carried
out, we shall soon see the spores increase in size, gradually lose their
green colour and then bud, and often a very active fermentation will
manifest itself. All the spores will be transformed, if the flasks are
perfectly air-tight.”[60]
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account