Ninkasi Director of Brewing Development Talks Chill HazeMar 06, 2017 Comments (0)
There are many opinions among beer drinkers regarding what is acceptable when it comes to beer clarity. At Ninkasi, we think that a great beer should look great, and for most of our beers that means clear, brilliant beer. To achieve this clarity, our clear beer is run through a centrifuge to remove particulates such as yeast, small hop particles or other suspended solids. The result is a brilliant, haze- free beer. Recently, some of our beers have developed sediment in the bottle even though they’ve gone through our centrifuge. I’ll chat a bit more about how and why this happens, but the most important things to know are that it is not bad for you and has no effect on the beer’s flavor. Also, this issue is not new to brewers and has been researched by brewing scientists such as Dr. Charlie Bamforth1 (UC Davis) and Dr. Karl Siebert2 (Cornell). Ben Chambers, our Quality Manager at Ninkasi, wrote on this same topic a few years ago as did Mitch Steele, previous brew master at Stone Brewing Co.3,4
Now for the what, how, and why.
(Left) Our beer clarity as intended. (Right) Our beer with chill haze.
What is beer haze?
Beer haze is the lack of clarity and requires three basic components5: 1) particles that don’t dissolve (colloids) when suspended in 2) a beer (colloidal suspension) and 3) light that is scattered when it passes through the beer. This interaction results in the phenomenon of haze. In beer, these insoluble particles can exist in two basic forms: Biological and non-biological. As the name implies, biological colloids are due to the presence of microorganisms, such as yeast in unfiltered or bottle conditioned beers. Non-biological colloids on the other hand are more common and are caused primarily by interactions between the proteins and polyphenols found in malt and hops. These interactions cause the formation of complexes over time and their rate of formation is largely dependent on temperature and the amount of protein and polyphenols in beer. Basically, as temperature decreases as time increases, the size of haze-forming particles also increases. If a haze forms only when the beer is cold it is called a reversible haze, or chill haze. Given the right conditions, this reversible haze may eventually form particles large enough to settle out and that are too big to go back into solution. This is known as irreversible chill haze which is what some consumers are noting in our beers.
In case you haven’t noticed, we love hops here at Ninkasi. Brewing beers with high hop loads requires carefully balancing the amount of polyphenols and proteins that end up in our beer. One small change to the levels of these compounds in our raw ingredients and the balance can tip, causing the formation of haze. Usually, we can catch these changes and account for them. However, sometimes we often don’t know when a certain change in the chemistry of our raw ingredients will cause haze formation.
What makes the prevention of permanent chill haze so difficult is that it usually forms in the bottles a few weeks after packaging. Because we strive to provide the freshest beers to our customers, this means that we don’t see haze formation in our beers until they have already left the brewery. For that reason, some beers with haze have ended up on the market.
We are reevaluating the way we examine our raw ingredients to ensure we have a proactive approach to keeping our beers haze free. In the meantime, if you come across a bottle of Ninkasi that looks hazier than it should, know that we are working to return our beers to their normal appearance and that chill haze has no effect on the taste of our beers.
Need to know more? Here are some additional resources mentioned above:
- Bamforth, C. W. Beer Haze. J. Am. Soc. Brew. Chem. 57, 81–90 (1999).
- Siebert, K. Effects of Protein-Polyphenol Interactions on Beverage Haze, Stabilization, and Analysis. J Agric Food Chem 47, 353–362 (1999).
- Chambers, B. Science Friday: Flavor Flakes. Ninkasi Blog (2015).
- Steele, M. Chill Haze, the more you know. Stone Brewing Blog (2011).
- Briggs, D. E., Boulton, C. A. & Brookes, P. A. Brewing: science and practice. (CRC Press, 2004).
About the Author
Daniel Sharp is our new Director of Brewing Development. He received his Ph.D. in Food Science and Technology at Oregon State University in Dr. Tom Shellhammer’s Brewing Science lab. His research studies focused on brewing factors that contribute to hop aroma in beer. A native Oregonian, Daniel earned a BA from the University of Oregon and his MS from Oregon State University. He has presented hop aroma research the Craft Brewer’s Conference, both the regional and national Master Brewers Association of the Americas meetings, and the World Brewing Congress. Daniel has received research awards from the Barth-Haas hop group and the American Society of Brewing Chemists. Basically, he loves hops.