Beer Clarity – What to Do About Hazy Beer
Since the arrival of the first pilseners, beer clarity has become an important aspect for most beers. American light lagers are among the clearest beers in the world due to their low protein and high adjunct content. Beer drinkers now expect their beer to be clear. So, how does this affect homebrewers? Commercial breweries use filtration to achieve crystal clear beers. As a homebrewer, there are several things you can do to improve the clarity of your beers.
The main cause of haze in homebrew is called chill haze. Where does this haze come from? It primarily comes from the malt used. Malt contains proteins, and its husks contain tannins (polyphenols). These proteins and tannins, along with other polyphenols, combine to form small complex chains that are too small to settle out. These protein-polyphenol complexes are soluble at warmer temperatures but become insoluble at colder temperatures, resulting in the haze you see in your homebrewed beer. These small protein-polyphenol chains can also combine with oxygen to form larger chains that can settle out, reducing chill haze. However, clear beer comes at the cost of oxidation and staling. There are steps homebrewers can take to reduce chill haze by either reducing the proteins or the polyphenols (also known as tannins), or both.
Ways to Improve Beer Clarity and Eliminate Chill Haze
To reduce the protein and/or polyphenol levels in your beer, you can decrease the amount of malt used in the recipe.
Consider adding adjuncts like corn, rice, or refined sugar, as seen in American lagers, Belgian-style tripels, or strong ales.
Using huskless malt such as wheat or rye can reduce polyphenol levels, but it may increase protein levels in your grain bill at low percentages. As the percentage increases to 40%, the polyphenol levels decrease to a point where the proteins have nothing to bind with, resulting in very clear beers.
Hops also contribute to polyphenol levels in beer. Using lower alpha acid hops as bittering hops incorporates more hop cone material into the wort, thus extracting more polyphenols. Using high alpha acid hops for bittering will reduce hop-derived haze in your beer.
Try adding a protein rest, which breaks down large proteins into smaller ones.
Achieve a good hot break by boiling the wort vigorously and ensure a good cold break by using a wort chiller (or even a pre-chiller). While a large percentage of malt polyphenols survive the boil and chill, only a relatively small percentage of hop-derived polyphenols do.
Switch to a malt with low protein or low polyphenol content in your recipe.
Use a fining agent during the boil. Adding bentonite in the last 15 minutes significantly reduces protein and polyphenol levels. Adding 10-40 grams per 5-gallon batch is recommended, but keep in mind that bentonite absorbs a lot of water, so you may want to use the lower end of the recommendation.
Adding fining agents after the boil to reduce protein levels is a common practice in commercial brewing.
Consider using a batch sparge method, which is known to reduce the extraction of tannins from the malt husks.
Filter your beer, starting with a larger filter and then switching to a smaller one for polishing.
Lager your beer at near freezing temperatures (32°F or 0°C).
Minimize aeration during bottling and kegging, as increased dissolved oxygen can promote permanent chill haze.
Other Reasons For Hazy Beer
Make sure the clarity issue in your beer is not caused by a wild yeast or bacterial infection. Haze in this case indicates a serious problem. Common bacterial infections in beer include Pediococcus damnosus, which produces a significant amount of diacetyl. Lactobacillus bacteria can introduce various flavors into your beer, some pleasant and some unpleasant. Coliforms are another type of bacteria that produce vegetal flavors. Haze caused by these infections is often noticeable in the bottle after fermentation. The appearance of haze in the bottle indicates a potential infection. The solution to bacterial infections is improved sanitation.
Yeast is another source of beer clarity issues. Yeast haze can result from wild yeast, mutated cultured yeast that cannot flocculate out of suspension, or cultured yeast known for poor flocculation properties. If the haze is caused by wild yeast, review your sanitation procedures, as the wild yeast may have been introduced during yeast repitching. Regardless of how it got there, it is clear that you should not reuse this yeast. Some yeast strains simply do not flocculate well, and fining or filtration may be necessary to achieve clarity.
A chemical haze may occur due to an imbalance of chemicals in your water. A deficiency of calcium during boiling can lead to a clarity issue called oxalate haze. Ensure that your boil has more than 25 ppm calcium (50 ppm is even better) by getting a chemical water analysis. When treating your water to lower bicarbonate levels, the calcium level may drop significantly. Add more calcium as needed. 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. Consider carbon filtering your water or diluting it with distilled water, reverse osmosis (RO) water, or bottled spring water to reduce these minerals below the threshold that causes haze formation.
Some brewers believe that skimming off the krausen formed during fermentation can result in better beer clarity. Using a blow-off tube can produce similar results when fermenting in a glass carboy. Another technique called “dropping” involves siphoning the beer from underneath the krausen, leaving the krausen and trub behind.