Ask Mr. Wizard

Beer Clarification Advice


Don Harwood — Oxfordshire, England asks,

What is your preferred method of clarifying beer, including removing chill haze? I’ve tried finings (isinglass, silica-based, and gelatin), and filtering down to 1 micron but never had results as good as just leaving the beer chilled for a month or two.


My preference of clarification method is based more on process constraints than any true affinity for a particular method. Gravity plus time, finings plus time, filtration, centrifugation, and combinations of these can all be used to produce clear beer. From a commercial perspective, I prefer methods that are fast and effective while consuming as little energy and producing as little effluent as possible. This column is geared towards homebrewers and I am going to steer my answer in the direction of ease and reliability.

As you point out, gravity never takes a day off and works well to clarify beer. Nothing really beats the simplicity of cold-aging, a.k.a. lagering, for beer clarification. The primary downsides to this method include failure to remove chill haze, beer damage during lagering, space and equipment requirements, and the relatively long waiting time for something that can be conducted in a much shorter timeframe. Let’s dig into a couple of these points in more detail.

Chill haze is formed when proteins and polyphenols/tannins react at cool temperatures to produce beer haze. Beer clarification at cool temperatures works well, but if the clarified beer is packaged and chilled to lower temperatures, chill haze forms. The best temperature range for cold, gravity clarification is between 30–34 °F (-1 to 1 °C). Chill haze can also be prevented by adding silica gels or PVPP to adsorb chill haze reactants. One practical challenge with using these stabilizers is that they are not completely removed by gravity sedimentation and require filtration for complete removal . . . this comment is really intended for commercial brewers who are reading this. The bottom line is that cold-aging works great for both ales and lagers as long as the aging temperature is less than the serving temperature.

Beer damage can occur during lagering if oxygen pick-up occurs during racking or if microbes start to slowly grow and produce off-flavors. Both of these problems are easy to avoid by using good brewing techniques when handling beer and keeping a clean environment that helps minimize microbiological headaches.

Personally, I do like fining for homebrewing because fining agents speed up the rate of clarification. It also minimizes storage time and the equipment that is tied up with aging beer. I am not a vegan and have no issue using isinglass. Of all of the beer finings used, isinglass is the winner when it comes to overall effectiveness. And when so-called auxiliary finings, for example acidic polysaccharides and alginates, are added to beer before isinglass, the combined fining action produces very clear beer with a compact sediment in a short timeframe. This method of fining is best exemplified by brewers of cask-conditioned ales. Gelatin is another source of collagen, but instead of coming from the swim bladders of fish (isinglass), gelatin is usually rendered from pig and cattle skin. Not all collagen proteins are the same and the collagen from gelatin is not as effective a fining as isinglass (also called piscine collagen).

For those brewers who don’t want to use porcine, bovine, or piscine collagen for beer fining, silicic acid sols are a great alternate. These products are added to beer after fermentation and rather quickly settle yeast, although the sediment is usually not as compact as the sediment from isinglass fining.

Filtration is definitely an effective method of beer clarification and is a method that I personally favor for many beverage clarification applications. However, I don’t think most homebrewed beer should be filtered because beer haze generally has zero effect on beer flavor, provided that beer is not overly yeasty. And when filters as tight as 1 micron are used, flavor stripping can occur.

Your question asked for my opinion, so here it is. Homebrewers should focus on brewing the best tasting beers as possible. Once that goal is accomplished and the brewing of great beer becomes normal, then cosmetic methods can be pursued. But even then, I question the objectives. Is it to produce Pilsner that looks like something from a bottle? Or is the goal to brew great beer with minimal special tools? For me homebrewing is not trying to emulate commonly available commercial beer at home. Why? Because it’s much easier to buy a six-pack of great beer if your goal is simply to drink laudable beer. Homebrewing to me is about brewing what I cannot buy at my local grocery store/beer store. My jam is playing with raw materials and technique so that I am tasting what I did to brew my beer. I wear wrinkled clothes and don’t polish my shoes, and I don’t need a filter at home to produce aesthetically pleasing beer.

Response by Ashton Lewis.