This will be the dullest brewing article you’ll ever read. It will stretch out over several posts, spanning several weeks. Nothing in it will be exciting. However, you should read it if you are serious about brewing. It’s nominally about cleaning and sanitation, but it’s really about brewing the cleanest beer possible.
In this article, I’ll cover what a brewer should know about bacteria and wild yeast in general, and the most common brewing contaminants specifically. I will cover where contaminating microbes live and how they can end up in your wort or beer. This will include a brief description of when beer is most vulnerable, although I’ve covered this before.
I will show how various brewing techniques either encourage or discourage the growth of contaminating microbes and how brewing clean beer requires more than just cleaning your brewing equipment and squirting sanitizing solution on surfaces that will contact wort. I will discuss various cleaners and sanitizers that are effective on brewing equipment and also discuss the pros and cons of no-rinse sanitizers.
Most importantly, I’ll show you how to assess the level of contamination in your beer. None of this — and I can’t stress this enough — will be exciting. It will lack the thrill of talking about what hop varieties go in an IPA or how decoction mashing affects the malt profile in a German-style lager. It will, however, be important. Your reward for slogging through it may potentially be to bring your beer to a new, higher level.
The Importance of Limiting Contamination
Before I dive in, let’s outline why brewing clean beer is important. First and foremost, heavily contaminated beer tastes and smells bad. In some cases, an undesirable mouthfeel may accompany the off flavor or aroma. Contaminated beer — no, it’s not “infected” — may be sour, phenolic, or have other characters that make it unpleasant to drink. Contaminated beer may also be cloudy or be lacking in foam. Beer that is only lightly contaminated, even below the level that definite off flavors or other negative characteristics are detected, can be robbed of the fresh character that beer in its prime should have.
Secondly, contaminated beer will not be stable. In other words, even if it is initially drinkable, it will go bad more quickly than it should. Finally, contaminated beer in the brewery can serve as a reservoir of contaminating microorganisms. One contaminated batch can lead to a series of contaminated batches.
Next week, I’ll post about bacteria and wild yeast, including the species of microbes most common found in contaminated beer. This will actually be fairly interesting, but don’t worry — later installments will get tedious fast.