When serving your homebrew to friends or family, it's fun to pour them something that has the look of a commercial craft beer they could have purchased at the store. While appearance may take a back seat to flavor and aroma when it comes to quality beer, serving a good-looking brew adds a level of professionalism to your final product.
Beer clarity can be difficult to achieve, but there are a couple of steps you can take that will get you on the road to clearer beer. The haze in homebrew comes primarily from two sources.
The first is simply the sediment in the bottom of the bottle that gets poured out with the beer. While it's inevitable that some sediment will end up in your glass, it can really be minimized to the point where it's not noticeable.
The second source of haze is soluble proteins suspended in the beer. These proteins come from both the grain and hops, and it's not as initially obvious as the sediment sitting on the bottom of the bottle.
In either case, with proper technique you can minimize the haze and serve crystal clear homebrew.
Secondary fermentation is really more about conditioning than it is about actual fermentation. The idea is to wait until fermentation is complete, usually about two weeks, and then transfer the beer into a secondary vessel to allow it age in bulk for a few weeks. Secondary fermentation allows the majority of the sediment to be left in the primary fermentation bucket or carboy, and allows time for more yeast to drop out of suspension. Less sediment ends up in your bottle, which leaves less to pour into your glass. This is the easiest way to eliminate the majority of particles or dormant yeast from your beer.
First check two different gravity readings and make sure they are the same, just as you would if you were going to bottle. Sanitize a 5 gallon carboy and an auto-siphon racking cane. Transfer the fermented beer to the carboy, leaving as much sediment in the primary fermentation vessel as possible, and let it sit in a cool, dark place for two to six weeks. When you're done, simply transfer to a bottling bucket and bottle as usual.
As an additional benefit, the extra time the beer spends in the secondary helps flavors to develop in bulk. This is particularly useful when brewing beer with high alcohol content or complex flavors, such as an Imperial Stout or a Belgian Tripel. Many homebrewers will use secondary fermentation every time they brew, specifically for the bulk conditioning benefits.
Hot and Cold Break
Hot break and cold break are terms for proteins that bind together during the boiling and cooling of your beer. Failure to produce sufficient hot or cold break will cause these proteins to stay separated and they will stay suspended in the beer even through secondary fermentation. You will end up with a cloudiness that will be almost impossible to get rid of.
The more rapidly you boil the wort on brew day, the more proteins will clump together. Hot break begins to show itself about ten minutes after the wort has boiled. If you look into the wort, you'll be able to see flaky particles floating around. Homebrewing author John Palmer aptly describes these flakes as looking like egg drop soup. If you see a lot of hot break in the wort, it's is an indication that you are doing a good, rolling boil and you're on the way to clear beer. The clumped particles are so heavy that they'll drop straight to the bottom of the fermenting vessel right away.
Cold break is formed after the boil. These particles bond together as a result of a rapid cooling at the end of the boil. The faster you cool the beer, the more cold break will be produced and the clearer your final product will be. The best way to produce a good cold break is to cool your wort with a copper wort chiller. Not only will a chiller cool your beer quickly to help with clarifying, but it also saves a lot of time at the end of your brewday. If you use a carboy for your primary fermentation vessel, you will be able to see the cold break float down right after you cool and transfer the wort. It looks like a hazy cloud slowly sinking to the bottom of the fermentor, and often makes your beer look two-toned for awhile.
Sometimes your brewing equipment won't allow you to have a rolling boil or rapid cooling of the wort. Finings are additions to the beer that will also cause the proteins to drop out of suspension. The most common finings used by homebrewers are Whirlfloc or Irish Moss. Just add half a Whirlfloc tablet or one teaspoon of Irish Moss during the last ten minutes of the boil to help the beer clear quickly. Many homebrewers keep these ingredients on hand and add them to every brew.