There are lots of things you can do to make your brew clearer when that quality is desirable for the style–and it’s not always.  But if you’re brewing a lager or pilsner and want to have the brew cleared there are a few simple things you can do that will help.  There are also additives you can put in your beer while fermenting, but we’ll save those for another time.  What we’re talking about here are things you can do whlie brewing to help out with clarification.

What causes cloudy beer?  Generally there are three main factors:

1. Proteins left from the malt and specialty grains that are suspended in the wort.
2. Small clumps of yeast that remain suspended after fermentation.
3. Yeast clumps in the bottle from bottle conditioning.

The first of these issues is most easily addressed at the time of the brewing. The simplest thing to do is to add Irish moss to your brew just about 10 minutes before the end of the boil.  This is a natural algae that grows along the ocean in Northern Europe and other places.  It attracts proteins from the brew and helps keep them clumped to the moss so that they strain out of the wort when you put it into the fermenter.  It’s called a fining agent, which is anything that is added to clarify beer. This stuff is not expensive and you only need about 1 tbsp. of it for a 5 gallon boil.

The second thing you can do about this issue is to cool the wort as quickly as possible, which helps the proteins drop out of suspension.  Fancy brewers do this with a wort chiller.  In our guide we provide some solutions that are simpler and several orders of magnitude cheaper.

So what about #2 and #3 then?  Several factors can affect that.  The primary one is which yeast you are using.  If your style is a clear one, then you ought to use a yeast that has high flocculation.  That’s a brewing term that means “high clumping factor.”  Basically the larger the clumps the yeast form, the more easily they drop out of suspension.  White Labs and Wyeast post this information about most of their strains, and some other yeast suppliers do as well.

In commercial brewing of bottle conditioned beers it is not uncommon to use a different strain of yeast to handle the bottle conditioning, one that produces less sediment.  That’s a bit extreme for home brewing, and not something we ever bother with.  If you’re hardcore you could experiment with this.  We advocate simple solutions, so we won’t go into it here.

As I said before there are other things you can add to the fermentation process to clear your beer and we’ll get into those another time.  Generally this is not needed.

Keep in mind that clearer beer is not always desirable.  Many styles look and taste better with a bit of clouding.

EDIT: Also see Part 2 in this series.