Chill Haze…The More You Know

Some of our fans may have noticed that our Stone IPA has not had its usual bright, golden, clear appearance lately. We have seen it ourselves: we are having issues with ‘haze formation’ (AKA ‘chill haze’) in this beer…and even some possible occurrence of so-called ‘floaties.’ We thought it might be useful to present an explanation so that everyone knows what is going on.

Some important things to know about chill haze and floaties:

  1. Chill haze will not affect beer taste at all. The chill haze has no flavor.
  2. There may be a slight increase in foaming as the beer is poured. The haze particles form nucleation points for CO2 bubbles. Again, this is not a flavor issue, as there is no taste difference.

So, what exactly is chill haze? (Hold on…we’re gonna go in deep! If you’re not interested in brewing science, it’s safe to stop here.)

The phenomenon known as chill haze is a colloidal haze that forms when proteins from the malt form a loose bond with polyphenols from hops. Without being overly technical [Too late Mitch! –ed.], this haze compound forms at colder temperatures (hence the name). And normally, when the beer warms back up, the haze disappears. You can observe this after you pour the beer into a glass and watch it clear up as the beer warms. Or take a bottle out of the refrigerator and let it warm up, and it will also get clearer. But eventually, especially if the beer is stored refrigerated (as it should be) the haze particles will not dissolve as the beer warms, and it then becomes known as permanent haze. Permanent haze tends to clump together in the beer and stay there. The scientific technical term for this permanent haze that clumps together is “floaties.”

Normally, our beers do develop a little bit of haze as they age. This is perfectly normal, and nothing to be concerned about. However, we don’t like the amount of haze that is forming in Stone IPA right now. It is too much, and we are working hard to get the situation back to normal. We especially do not like to see floaties in our beer! Here are some things that we are looking at to resolve this situation:

  1. Because chill haze is formed from protein and tannins, any change in composition in your brewing ingredients can result in a change in the amount of haze that forms. Thus, in years where malt has higher protein or beta glucan levels, we can see more haze form in our beer. Dry-hopped beers tend to form more haze, because the increased hopping adds more polyphenols to bond with the protein. So we are intensely studying our incoming malt to evaluate the changes in protein, beta glucan, and other factors that might be contributing to the haze.
  2. Chill haze can usually be effectively removed from beer before it is bottled. The traditional brewing procedure is to chill the beer after fermentation close to freezing, and age it several days or weeks before filtration, which forces the chill haze particles to form in the beer. Then, when the beer is filtered, the haze particles are trapped on the filter bed, leaving the beer clear and haze-free. That is what we normally do here at Stone, and up until now, it has been effective. However, one issue we are struggling with as we’ve grown is our chilling systems cannot keep up with our production, and some tanks are taking too long to reach chill temperatures. We suspect that these tanks are not getting good chill haze formation prior to filtration, and so the haze forming compounds are still in the beer after filtration and form haze and the dreaded floaties as the bottled or kegged beer is kept refrigerated.
  3. There are other techniques that can be used to reduce chill haze, including adding Irish Moss or other types of protein flocculants in the brewhouse. These compounds bond with the proteins during the kettle boil, creating larger, solid particles that are settled out as “trub” in the whirlpool. They are added to enhance the trub formation during the kettle boil, which is important, because wort needs to be good and clear before adding yeast. Excess protein in wort can impact yeast performance and beer flavor. An added benefit is that the decanting of clear wort off the trub effectively removes much of the protein that would otherwise go on to form chill haze in the finished beer. At Stone Brewing Co., we use a product called Whirlfloc in the kettle boil, which is used by many, many brewers. But as the beta glucan level of our incoming malts change (thanks to Mother Nature), we need to regularly re-evaluate the amount of Whirlfloc we are adding, and we are conducting those tests right now.
  4. We are also auditing and evaluating our filtration process and centrifugation process to make sure there isn’t something there that is contributing to the increase in haze formation.
  5. And there are other, more severe methods that can be used to remove chill haze components, such as adding silica gel, PVPP, or papain to the cold beer as it ages. These products react with either protein or polyphenol and form large haze particles that are easily filtered out. This is the kind of technique that is used by bigger brewers because it is generally foolproof. But it’s just not us to resort to these methods.   We’ve never added anything like that to our beers at Stone.  We don’t want to over-process our beers, nor do we want to start adding anything now that could affect flavor. We will get this solved without resorting to adding chillproofing agents.  Interesting that a chill haze beer can actually indicate a purer beer (even though the novice might interpret the opposite).

We’re telling you all this because we don’t mind just laying it on the table.  Even though there’s zero flavor difference, we love the look of a crystal clear Stone IPA just as much as you do (and also realize the potential for a hazy one to be misinterpreted in our often over-sanitized and processed world).  Please bear with us as we work diligently to solve this situation, and in the meantime, enjoy your slightly hazy Stone IPA just as much as any other time.