Homebrewing: Cleaning and Sterilisation
Our lovingly prepared homebrew provides the perfect environment for brewing yeast
to flourish in. Unfortunately, it is also the perfect environment for the
millions of bacteria and wild yeasts that are floating round in the air and
living on our brewing equipment. Nearly all of these will harm the flavour of
our brew if they are allowed to take hold.
To prevent these unwanted nasties from munching on the precious malt sugars
which were meant for our yeast, we need to clean and sterilise ALL the equipment
that our beer will touch.
Cleaning
Brewing equipment, like our cutlery and crockery, needs to be thoroughly
washed and cleaned. Unlike them, it also needs to be thoroughly rinsed,
following cleaning, to remove any traces of detergent. Traces of detergent in
the finished beer will affect the surface tension and result in poor head
retention (i.e. a flat, unattractive pint!). Sterilising Agents
Sterilisation is different from cleaning; it involves rinsing the equipment
in a prepared solution which is designed to kill bacteria and yeast.
Strictly speaking, the 'sterilising' done by us homebrewers should be called
'sanitising', as we don't kill off all the life forms on our equipment, but
simply reduce them to a harmless level. However, I'll assume that we all know
what we mean by 'sterilising' in homebrew context and I'll continue to use that
term! There are
two main types of sterilising agents available to the homebrewer: -
- Sulphur dioxide-based sterilisers (e.g. sodium metabisulphate)
- Chlorine-based sterilisers (e.g. bleach)
Of the two, I would recommend chlorine-based sterilisers, as they are more
effective against wild yeasts, and actually kill them, rather than just inhibiting
growth (as sulphur dioxide does). While is is possible to make your own
chlorine-based steriliser from household bleach, I would recommend buying a
commercially available one, especially if is combined with a cleaner (which
saves a lot of work!) I use VWP Cleaner Steriliser, which comes in the form
of a white powder which you dissolve in water.
Sterilising Tips
- Sterilise equipment as near as possible to the time it will be used
(certainly no more than an hour before)
- Rinse thoroughly in clean tap water just before use (otherwise the
sterilising agent will kill your brewing yeast!) I rinse 5 times to ensure
all steriliser is removed
- If it moves, sterilise it!
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