Some Causes of Hazy Beers – A Summary

From the Journal of the Institute of Brewing

SOME CAUSES OF HAZY BEERS – a summary (1924)
by C. G. Matthews, F.I.C.

Tabulated Causes of Haze and Turbidity in Beers as gathered from the References, etc.

A. I.   Amorphous particles due to proteins or hop resin or both;
II. Albumin turbidity due to metals, iron, copper and tin, but especially the two last
named.  Nickel is a possibility.
B.  Cooling as a cause of separation or precipitation of gluten and hop resin.
C.  Effect of CO₂ as a cause of separation or precipitation of gluten and hop resin.
D.  Difficulties ascribed to diffusible peptones causing turbidity.
E.  Starch turbidity especially from steely or badly-modified malt.
F.  Systematic testing of hazy beers. (P. Lindner.)
G. Resin turbidity.
H. Calcium oxalate and turbidity.  Abnormally low acidity of beers.
I.  Turbidity from crushed hop seeds.
J.  Temperature in relation to haze and turbidity.
K.  Colloids and the ultra-microscope.
L.  Unclean bottles and vessels.
M.  Effect of imperfect attenuation.
N.  Gluten turbidity in the light of changing acidity.
0.  Effect of formaldehyde as a possible cause of turbidity.
P.  Advantages and disadvantages of pre-mashing.
Q.  The electrical state of a beer.
R.  Wild yeasts as a cause of haze.  Imperfect sterilisation.
S.  Detrimental effect of C0₂ containing oxygen.
T.  Haze in low gravity beers.
U.  “Trade” causes of turbidity, bottles, agitation, changes of temperature, stoppers and
light.
V.  Caramel as a possible cause of haze.
W.  Amorphous haze (see also first clause of A.) and temperature.

Brewing has come a long way.  Not so many years ago “hazy” was actually seen as problematic and a flaw to be overcome – imagine that!  If you’re actually trying to brew a hazy beer, you now have more choices than “one from column A and one from column B.” I’m with my friend Neil B. on this one, “Bring back clear beer!”