Chill Haze

I am one of those brewers who believe in sticking to the fundamentals of brewing and then bringing in special tools and brewing aids only after knowing that the fundamentals are being addressed. It is really tempting to begin an answer about chill haze with a long discussion about fining agents and how proteins and polyphenols (tannins) can be selectively removed by the proper selection and use of these compounds. You may discover you need to travel down that road and if you do need to use finings to address your chill haze issues you can research this topic at that time.

It is possible to brew bright, stable beer without using finings, but this does not happen by accident. You are new to all-grain brewing, so there are several things that you need to make sure you are doing correctly before you begin looking for a silver bullet to solve the problem. Here is a short list of items that I would begin reviewing to address your quest for clarity:

1. Malt milling can influence beer clarity if the crush is very fine and you carry an excessive load of particulates into the kettle. Since malt husk contains tannins that react with proteins to form haze, an increase in these compounds from over-milling and poor wort clarity flowing from the lauter tun can cause haze problems in the finished beer. This is one of several reasons that brewers are careful about malt milling and mill gap adjustment.

2. When wort first flows from the lauter tun it is normal for the wort to be cloudy and a bit weak since the lauter tun bottom is normally covered with water prior to filling. For these reasons the wort is recirculated by gently pumping or pouring the “first wort” flowing from the lauter tun to the top of the mash. This flushes the weak wort to the top of the mash and allows the mash bed to establish its filtration properties. The recirculation process in a commercial brewery is typically continued until the wort is clear and the specific gravity has risen to the expected first wort strength. An inconsistent wort flow rate during wort collection can lead to spikes in turbidity so keep the wort flow steady during collection.

3. A vigorous kettle boil for at least 60 minutes is very important for beer flavor and beer clarity since certain undesirable aromas and protein and tannin fractions are removed during the boil. Many brewers add Irish moss, a good source of kappa-carrageenan, to wort towards the end of the boil in an effort to increase the size of protein flocs. Since the large flocs settle faster than the smaller and more fragile chunks of protein “break,” or denatured proteins and protein fragments, Irish moss aids in removing these haze-active proteins from wort and beer. With or without Irish moss, a vigorous boil is a must. Almost all commercial brewers use whirlpool vessels to separate protein break and pelletized hop residues (when pellet hops are used) from wort following the boil. Many homebrewers have begun using whirlpool-type vessels for the same purposes.

4. Rapid wort cooling after the boil is also very important if you want to brew bright beer. When wort is rapidly chilled “cold break” forms and this settles out in the fermenter. Cold break, like hot break, is comprised of proteins and tannins. Cold break formation is hindered by slow wort cooling; this is one reason why wort chillers are so valuable.

5. Cold storage prior to packaging is the closest thing to a silver bullet when it comes to producing clear, stable beer. The reason this method is so effective is that it causes chill haze formation and, given enough time, allows for the haze to settle from the beer. Most chill proofing aids accelerate this process, which is one reason why they are so critical in commercial operations, and do work very well, but at the end of the day are not required if you have time. The important thing about this process is temperature; you want the beer close to freezing, 30 °F (-1 °C) is perfect to cause as much chill haze formation and subsequent settling as possible. You will want to carefully rack your beer off of the sediment before bottling. Since yeast will also settle during this time, it is often a great benefit to add a small amount of yeast prior to bottling.

After you focus on the five fundamentals above, you should see the fruits of your labor. If you still want clearer beer, send us another question and I will discuss finings and enzymes that can be used to combat haze!

Response by Ashton Lewis.