From the HBD Archive
From: olson@antares.cs.Virginia.EDU
Subject: dreaded chill haze
Date: 1989-12-05 20:08:57 GMT

Tim Harris writes:
>If fact, every time I cool any of these beers they become cloudy. Now all
>the chemistry buffs are thinking - ah, a percipitate! That's probably what
>it is, but what is it and why does it come out of solution at cold temp's?
>Or is the yeast somehow getting stirred up by two hours of sitting in at 45
>degrees (not what I consider worth waking up for)? Most importantly how do
>I avoid this problem in the future? The beer tastes pretty good, but
>a little yeasty still.

Tim, you are suffering from the Dreaded Chill Haze. There is some
discussion in The Complete Joy of Home Brewing, to my recollection
going like this: the wort contains a variety of things besides sugars and
starches, notably tannin (from the grain husks) and proteins. At low temps
the tannin bonds weakly to the protein and comes out of solution, creating
a haze. (don't shoot me, chemists! I'm just a dumb brewer!) Now my
understanding is that this has no effect on the flavor at all, unless you
have a LOT of tannin. TCJoHB's unhelpful advice is "If the haze bothers
you, try drinking from an opaque mug". But I like to see the color of my
brew; presumably you do that by controlling either the protein or the tannin.
To do the former, I believe you have to mash -- right, experts? Or maybe be
more careful about excluding trub after the boil. To control tannin, you
should at least be careful not to boil any grain -- put it into the wort cold,
and strain it out when the wort finally reaches a boil. There's nothing us
extract brewers can do about the tannins in the extract, though. Finally,
you can do what I do: cheat! A couple of hours (12?) before bottling, stir
in a tablespoon of Polyclar, which is basically pulverized plastic. This
adsorbs tannins and sinks to the bottom. Works great for me, and also
gives me that warm glow that comes from being politically incorrect... :-)

- --Tom Olson (

By the way, would some kind soul send me the current price and address for
subscribing to Zymurgy? The back of my TCJoHB says $17, bet that's wrong...

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