This is the first part of my detailed series on beer clarity and finings, and is based on a presentation I did for this year’s National Homebrew Conference on the same subject. In this first part, I’m going to cover what beer clarity is, how its defined and measured and the potential causes of haze or clarity problems in beer.
When Clarity Matters
Crystal clear beer is a goal for many beer styles. Commercial brewers go to great lengths to assure the clarity and stability of their finished beers. However, clarity does not always matter. For darker beers like Browns, Porters, Bocks, and Stouts, clarity is not as important, so we see many haze producing malts and adjucts added – since you won’t notice them in the finished product. Some beers are even intentionally hazy, such as hefe-weizen which is served with yeast intentionally mixed in – either by storing kegs inverted and turning them before serving, or bottle conditioning and serving them with the sediment.
Understanding and Measuring Haze in Beer
Haze in beer is nothing more than suspended particles that reflect light. The most frequent sources of haze are from yeast cells, proteins and polyphenols (tannins), but bacteria, foreign material, and even excessive finings can all contribute to haze in finished beer. Beer haze is measured using a Radiometer haze meter, a special device that shines light through a sample of beer and measures the intensity of the light reflected off particles in the sample at a 90 degree angle, typically on an EBC scale.
Even a high quality haze meter has its limitations due to a phenomena called “pseudo-haze”. Pseudo haze is when you have haze that is detectable by a haze meter, but may not be visible to an observer. Pseudo-haze is caused by small particles that reflect light but don’t affect the clarity of the finished beer.
The term “turbidity” is used to describe the particles that are visible, and pseudo-haze is the difference between the haze measured by the meter and the “turbidity” actually visible in the finished beer. Pseudo-haze can be a real problem for commercial brewers who want to consistently measure and control the haze stability of their beer.
Types of Haze in Beer
There are two major types of haze in beer. The first is a chill haze, which often occurs at near freezing temperatures but disappears as we warm the beer. The second is a permanent haze, which is simply present all the time. Chill haze, however, can be a major concern even for beers served at warmer temperatures since chill haze will often become a permanent haze over time as the beer matures.
Potential Causes of Haze in Beer
The vast bulk of effort in controlling clarity in a finished beer is focused around proteins and polyphenols (tannins) which primarily come from malt and hops. These will be covered in detail in part 2, but these two ingredients are the cause of most chill haze as well as permanent haze issues in a finished beer. A secondary concern is suspended yeast, which often contributes to clarity issues when a beer is young. While yeast does not often contribute to permanent clarity issues, some steps are needed to assure that yeast falls out of the beer quickly after fermentation.
The other causes of haze which are less common include:
- Calcium deficient worts (causes Oxalates)
- Wheat derived adjuncts (causes Pentosans)
- Inadequately modified malt (Beta-glucans) – though very uncommon with modern malts
- Dead bacteria from an infection
- Damaged or overstressed yeast (Induces carbs and proteins)
- Lubricants, excessive finings or other foreign material in the beer
That’s a quick overview of measuring haze and the major causes of clarity issues. Next week in part 2, I’ll go into detail on proteins, polyphenols and yeast and begin to discuss how you can improve the clarity of your beer using both techniques and finings.
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Excellent stuff! Looking forward to Part 2.
Hey Brad,
Great start to article on clarity and I look forward to part 2. Clarity has recently been a concern to me since I am currently conditioning a cream ale; by far the lightest beer I’ve ever made, in color and taste. I have been brewing for over 30 years and all grain brewing with pure yeast for well over 25 years. I never thought that much about clarity and how it might also affect taste, head retention and the likes; but thinking back in general the best tasting homebrewed and craft beers I have had were generally either crystal clear or almost, with a few exceptions. Those that aren’t generally, while may be well brewed beer, just have something in their flavor that is hard to put one’s finger on, but one might say that they, in general, don’t taste quite as “clean”, (whatever that may mean) as a clear beer. Understanding that some beers are meant to be cloudy or hazy. Those particles typically do have some kind of flavor or taste associated with them.
Most all of my brewing mentors in my early days made crystal clear beers either by fining and cold storage or by filtration. If you will allow me to drop a name, one of my mentors where I lived back in my early brewing days was George Fix, who lived fairly close to where I lived and was dean at the university. Back then he was writing his books and doing a lot of research. As good as George was I felt my other two older mentors at the time actually made beers I liked better, not that there was anything wrong or bad with George’s beers; he made some of the cleanest tasting homebrewed beers I’ve ever had. I tell you this not to brag, but to show you the depth of knowledge I was exposed to back in my early brewing days.
I have seen a beers flavor drastically improve within minutes through filtration at a friends house back in the 80’s; he cold filtered his light beers after carbonation with a plate filter he had fabricated, and I swear he made the best tasting light beers I have ever had, and I am talking about really light American style beers, before or since then. He was truly a master. While I am not an advocate of filtration on the home scale, mostly because of how much trouble and time it takes. I do believe that clarity can have a major effect on how a beer taste, and can usually be adequately achieved with cold conditioning and fining..
Finally, the point I originally wanted to make was something I read today in Greg Noonan’s book New Brewing Lager Beer, which he states on page 195 under the subject of Fining: “Whether or not the beer is being lagered, fining improves its head retention, lacing and clarity, and reduces aging times. It precipitates degenerated yeast cells, haze proteins, and tannins out of the beer. Gelatin and isinglass act as fining substances by enveloping suspended particles in their matrix, and gelatin further combines with tannic acid to form an insoluble precipitate.”
I don’t need to tell you how well researched Noonan’s book is, but Wow, didn’t realize how many things fining could achieve to include a clean taste; head retention and reduces aging times… sign me up for something that really isn’t that much work or trouble in producing a product I am proud of.
Well, sorry for being so long winded and going off on some tangents, but I just felt that some of this information; particularly that from Noonan’s book might be something you would want to reference. I’m sure you have read the same information in past, but if you’re anything like me, it’s always good to hear it from someone else’s prospective at times.
Thanks for all of the great work you do, and I look forward to your future articles.
Randy Rancier
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