Chill haze from crash cooling?

[seanppp]

I was told recently by a professional shift brewer that crash cooling too fast causes chill haze. I don't understand how this could be, chemically speaking.

Is he correct? If so/if not, why?

 

[maddcow]

I don't know if crashing too fast causes the haze, but crash cooling will cause a haze. There are still proteins in your beer. As temperature drops, the protein tends to clump together to form bigger particles which is seen as haze. If left long enough (a few weeks?), the particles should get heavy and eventually drop out. Many commercial brewers use the method of crash cooling on purpose to create haze. From there, they have an easier time filtering out the proteins and making a clearer beer.

 

[GHBWNY]

Cold-crashing does not *cause*, but emphasizes the real reason for chill haze, which is leftover proteins in the wort clumping together due to not having fallen out of suspension (hot break) during the boil. Finings like Irish moss added at the end of the boil will help the proteins coagulate. Along with a good hot break, a fast cold break (getting the wort chilled down as quickly as possible) will also help the proteins flocculate and settle out, giving you a clearer, tastier beer. Chilling in the brew kettle as opposed to in the fermenter will help leave more of the cold break material behind.