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Protein haze

Physical and stabilityRecoverable if caught early

Nothing. It looks like a fine, even mist that appears after the wine has been left somewhere warm.

What causes it

Heat-unstable proteins in white wine coagulating when the bottle gets warm. The wine is perfectly sound.

Detection threshold

Visible against a light. Confirmed with a heat test: 80C for two hours, then cool and look.

What you can do

Bentonite fining before bottling, at the rate a bench trial gives rather than a guessed one.

How to prevent it

Heat-test every white and rose before bottling. This is the most common reason a home white goes cloudy in summer.