Fault

Permanent haze

Cloudiness that does not clear with warming, usually from incomplete starch conversion or irreversible protein complexes.

Also called starch haze, colloidal haze, cloudy beer, cloudy.

What it tastes and smells like

Persistent haze in a style meant to be bright indicates a brewing problem, but it is cosmetic and harmless.

Not a safety issue. Beer’s alcohol, hop compounds and low pH make it inhospitable to organisms that cause illness.

Cause	Stage	How often	Who can act
Starch left unconverted in the mash, from too short a rest, too high a temperature, or insufficient diastatic power in the grist.	mashing	most common	brewer
Protein-polyphenol complexes that have become permanently insoluble with time and oxidation.	conditioning	common	brewer

Brewer: Confirm conversion with an iodine test before lautering, and check the grist has adequate diastatic power for its adjuncts. (prevents)

Steps that can produce this fault when they go wrong. Each links to what the step is for and how it is controlled.

Cellar conditioning — Receive, stillage, vent, fine and temperature-manage cask beer in the pub so it reaches the drinker in condition.
Cold crashing — Chill finished beer sharply to near freezing to force yeast and haze-forming material out of suspension before packaging.
Fining — Add a substance that binds with haze-forming material and drags it out of suspension, clarifying wort or beer without filtration.
Mash pH adjustment — Bring the mash into the narrow pH band where brewing enzymes work properly, using acid, salts or acidulated malt.

What BeerHQ knows about this, and how. Every statement carries the state of the evidence behind it rather than being presented flatly as fact.

BeerHQ treats the stable haze of a New England IPA as a style characteristic rather than a fault, because it is deliberately produced and does not clear on warming as an unintended chill haze would.
BeerHQ’s own reading