Beer clarity has become an important aspect of most beers since the first pilseners arrived. American light lagers are some of the clearest beers in the world with their low proteins and high adjuncts. Beer drinkers have come to expect their beer to be clear. So how does this affect the homebrewer? Commercial breweries use filtration to get those crystal clear beers. For you the homebrewer, there are quite a few things you can do to improve the clarity of your beers.
The number one cause of haze in homebrew is called chill haze. Where does this haze come from? It comes primarily from the malt you use. The malt is full of proteins and its husks are full of tannins (polyphenols). These proteins and tannins (along with other polyphenols) cross-link to form small complex chains which are too small to settle out. These protein-polyphenol complexes are soluble at warmer temperatures but will become insoluble at colder temperatures, and form the haze you see in your homebrewed beer. These small protein-polyphenol chains can combine with oxygen to form larger chains which can settle out, reducing chill haze. But the clear beer comes at a price, oxidation and staling. There are some things the homebrewer can do to reduce chill haze. To reduce chill haze caused by protein-polyphenol linking is a matter of reducing the proteins or the polyphenols (aka Tannins) or both. There is a product on the market made by White Labs called Clarity Ferm. Clarity ferm cleaves polypetides (a protein fraction) so they cannot
bond with polyphenols (tannin). This product is also known as Brewer's
Clarex. One incidental but important side affect of using Clarity Ferm, it produces gluten-reduced beers (The majority of beers test below 10ppm gluten when used in the correct dosage). Here are some thing you can try:
Check to ensure that the beer clarity issue isn't caused by a wild yeast or bacterial infection. In this case, haze is an indication of a serious problem. Common bacterial infections in beer include Pediococcus damnosus which generates a lot of diacetyl. Lactobacillus bacteria can produce many flavors in your beer, some pleasant as in a lambic, and some not so pleasant. A third type of bacterial infection comes from the coliforms. These types of bacteria produce vegetal flavors like old celery in your beer. You will most likely notice these hazes in the bottle after fermentation. The appearance of haze in the bottle is an indicator that you may have an infection. The solution to bacterial infections is better sanitation.
Another source of beer clarity problems is yeast. The yeast haze can come from wild yeast, a cultured yeast that may have mutated and can't flocculate out of suspension, or a cultured yeast noted for its poor flocculation properties. If it is from a wild yeast, look at your sanitation procedures. The wild yeast may have been transferred from repitching the yeast from another fermentation. Regardless how it got there, it's obvious that you shouldn't reuse this yeast. You will find that some yeast cultures are just poor flocculators and recommend fining or filtration to get a clear beer.
You may be experiencing a chemical haze caused by an in-balance of chemicals in your water. A deficiency of calcium in your boil can cause a clarity problem from a chemical haze called oxalate haze. Make sure you have more than 25 ppm calcium (50 ppm is better) by getting a chemical water analysis. When treating your water to lower bicarbonates, the calcium level may have dropped considerably. Add more calcium back as necessary. Minerals such as iron and copper at levels exceeding 1 ppm, and tin at levels exceeding 0.1 ppm can also cause a chemical haze. Try carbon filtering your water or diluting with distilled water, RO (reverse osmosis) water or bottled spring water to reduce these minerals below the haze-forming threshold.
Some brewers believe that skimming the dirty head formed during fermentation will result in better beer clarity. If you want to do this, Al Korzonas in his book Homebrewing Vol. 1 suggests that you may be reducing the bitterness levels in your beers and that the other benefits are minimal. Using a blow-off tube produces similar results when fermenting in a glass carboy. Another procedure is called "dropping" whereby the beer is siphoned out from under the krausen, leaving it and the trub behind.
Above table adapted from John J. Palmer's How To Brew.
As you can see, there is a lot you can do to improve your beer clarity. To some homebrewers a little haze in their homebrew is not important because it does not affect the flavor or head retention. We as consumers have been conditioned to look for beer clarity in crystal clear beer, and to think there is a fault if the beer is hazy. If you want to enter competitions, haze is not acceptable in all but a few styles. If you try all the above mentioned tips and your beer is still hazy, try one of the brewing forums. There is a wealth of information out there waiting to be tapped on beer clarity.
References: Information for this article about beer clarity was adapted in part from How To Brew by John Palmer, Homebrewing Vol. 1 by Al Korzonas, and The New Complete Joy of Home Brewing by Charlie Papazian.
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