How Fining Works
A fining agent is added to wine, where it chemically bonds with specific unwanted compounds. The agent-particle complex becomes heavy enough to settle to the bottom, and the clarified wine is then racked off.
Common Fining Agents
- Bentonite — a clay that removes excess proteins (prevents haze in white wines)
- Egg white (albumin) — softens harsh tannins in red wines; traditional in Bordeaux
- Casein (milk protein) — removes browning and off-colours in white wines
- Isinglass (fish bladder) — creates brilliant clarity in white wines and sparkling wines
- PVPP — a synthetic agent that removes browning compounds
Vegan and Unfined Wines
Traditional fining agents (egg, casein, isinglass) are animal-derived, making those wines non-vegan. Increasing demand for vegan wines has led to wider use of bentonite, pea protein, and potato protein alternatives. Some winemakers skip fining entirely, labelling wines as "unfined."
When to Fine
Fining is typically done before bottling. Over-fining can strip desirable flavour and body, so winemakers conduct bench trials to determine the minimum effective dose.