Eliminating chill haze

Chill haze is the product of protein and polyphenol (tannin)
interactions in beer and occur when beer is chilled, hence the name
chill haze. There are various methods aimed at chill haze reduction and
they all either are based on reducing the content of chill haze proteins
and/or polyphenols. The first thing brewers can do to minimize haze is
to begin with low protein raw materials. This is one of the reasons that
the protein content and degree of modification of proteins in malt are
of importance. Although some brewers frown upon the use of adjuncts,
protein dilution of wort is beneficial to a certain degree when higher
protein barley is used for malting.

Irish moss added in the kettle reacts with hot break to form larger trub
flocs that settle more quickly than smaller flocs. Many brewers today
use silica gels prior to filtration to remove even more protein.
Polyvinylpolypyrrolidone (PVPP) can be added alone or in conjunction
with silica gel, and PVPP is used to remove the polyphenol component of
haze. In all cases, a cold aging step prior to packaging allows chill
haze to form and permits its removal by gravity sedimentation or
filtration. Ale brewers often add isinglass finings to remove yeast, but
isinglass also removes some haze forming proteins.

In my opinion neither mash time nor mash profile are significant
contributors to chill haze. It is certainly true that longer mashes
remove more protein in the mash than shorter mashes, but long mashes and
those mashes using low temperature protein rests are not commonly used
to specifically address chill haze.

I have a Teutonic view of chill haze control and it seems to work for
most of our beers. We begin with high-quality 2-row malt that tends to
be on the lower end of total protein (10.5–11%). In the brewhouse we use
the mash profile that works for what we want in terms of beer flavor
and no special concern is given to haze control. During boiling we
evaporate about 6–8% of the kettle full volume and no finings are added.
We use no finings before filtration, but we do hold our beers awaiting
filtration at 30–32 °F (-1–0 °C) for several days to allow chill haze to
form. This works for all of our beers except beers that are dry-hopped
as well as those that begin with under-modified Pilsner malt. If I had
to correct the haze in these two beers I would use PVPP to go after
tannins in dry-hopped beers and silica gel for the haze forming proteins
associated with under-modified malt. But a little haze is not a bad
thing in some beers and I prefer to let the flavor express itself
without excessive meddling.

Response by Ashton Lewis.