Cleanliness
Apart from bottling before the primary fermentation is finished, most
of the troubles experienced by home brewers are caused by lack of
cleanliness. The wort, and the beer itself, make an almost ideal medium
for the growth of bacteria, wild
yeasts and other moulds, which if they
gain access will spoil our beer and cause off' flavours.
The big breweries employ a staff of highly trained microbiologists whose
duty it is to keep the yeast strains pure and to check for contamination
of the beer. In fact, the standard of hygiene in the big breweries would
not be matched by quite a few of our hospitals. Of course, at home, we
do not have the facilities to do this, but if we are careful, we should
experience no trouble at all.
At all times, we should observe the normal standards of hygiene, but
there are some other factors that we should keep in mind.
One such factor is that bacteria, wild
yeasts and other organisms that
are likely to contaminate our brew, are airborne. Invariably they are
found in dust.
Every home, no matter how clean, has its quota of them. Those of us
who live where we experience a hot humid period during the summer will
know how moulds suddenly start growing on things, even our shoes. If
they will grow on shoes, imagine how much they would prefer the
wort,
specifically made so that the yeast we add will grow and multiply as
fast as possible thus giving us a good fermentation.
Another point we should remember is that under some circumstances, the
oxygen of the air itself can be regarded as a contaminant. It can cause
oxidation in our beer and produce 'off' flavours.
What can we do to guard against these factors? Firstly, we can make
certain that our equipment is clean and sterilized. Then we can be
careful about our methods. Do not cover your brewing container with
dusty, dirty cloth or bags, in an effort to keep the brew warm. When you
take these off to check the brew, dust will be disturbed and can get
into the brew. If you wish to cover the equipment, use only clean cloths
and preferably ones that do not shed much lint.
Avoid as far as possible making and bottling your brew in places where
there may be dust and dirt blowing around—such as in some garages.
When syphoning the brew it should be possible to keep the container
lid partially ciosed.
Do not keep removing the lid in order to check the brew, this only
increases the chance of contamination. Also, since carbon dioxide is a
very heavy gas, it forms a protective layer on top of the brew and you
will disturb this layer. Of course some skimming and checking of the
brew is necessary—do this as quickly and as cleanly as possible.
Above all, think continuously about possible sources of
contamination. If you do this, you should never have any failures.
Sterilization can be effected by boiling. However, this is impractical
for home brewers. Therefore we must use chemical methods of
sterilization.
The best and easiest chemical to use is sodium metabisulphite. This
is a white powder and it is dissolved in lukewarm water for use. Its
solution contains sulphur dioxide which is the sterilizing agent. Sodium
metabisulphite should be available at the store where you buy your other
ingredients. If not, chemical supply houses have it or your local
chemist should be able to obtain it for you.
The solution, for use, is made by dissolving one heaped teaspoon of
sodium metabisulphite per pint of luke-warm water. If you smell the
solution very carefully, you will notice the characteristic choking
smell of sulphur dioxide.
Articles are sterilized by soaking them in this solution. With
containers and bottles, the solution is swirled around the inside making
certain that the entire surface contacts the solution. In practice, the
solution may be poured from one container or bottle to another. It can
be re used until there no longer is any smell of sulphur dioxide coming
from the solution. The solution will keep for several months in a
tightly corked, glass or plastic bottle. Store this in a cool, dark
place.
A little of this solution left in your empty brewing containers will
keep them clean and sweet smelling.
All articles should be rinsed with clean water to remove the
sterilizing solution before use.
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