Fining

How fining works

The principle is simple. A fining agent is added to the wine, where it binds to the target compound to form larger particles. These particles then fall out of suspension, either by gravity (racking) or with help from filtration. The wine is left cleaner, more stable and often more polished on the palate.

The choice of fining agent is a craft decision. Bentonite is aggressive on protein but can strip colour from reds. Egg white is gentle and traditional, the classic choice for top red Burgundies, but unsuitable for vegans. Isinglass is excellent for whites and rosés. Casein, used historically in fino sherry production, is effective at removing oxidised browning.

Vegan and allergen considerations

Most traditional fining agents are animal-derived, which is a problem for vegan and vegetarian consumers. The UK has responded with a clear labelling rule: any wine fined with a milk, egg or fish product must carry an "contains milk", "contains egg" or "contains fish" allergen warning. Many producers have moved to plant-based alternatives, including pea protein, potato protein and activated carbon, which are equally effective and avoid the allergen issue.

Several UK producers, including Litmus Wines and Davenport Vineyards, label their entire range as vegan-friendly. The Vegan Society's sunflower-trademark is the most common certification mark on UK wine.

Fining in English winemaking

English wines are fined less aggressively than in many other countries, partly because the cool climate already gives clean, well-balanced base wines that need less intervention. Most English still whites are fined lightly with bentonite or isinglass, then filtered. English sparkling base wines are usually fined to remove excess protein that would otherwise cause haze in the finished bottle, then filtered before the second fermentation.

Red wines, especially Pinot Noir, are often not fined at all. The tannins settle out naturally during barrel ageing and racking, and the winemaker wants to preserve as much colour and texture as possible. Some premium producers skip fining entirely and rely on gravity and time.

Fining vs filtration

Fining and filtration are different. Fining is chemical, in the sense that a binding agent is used. Filtration is mechanical, using pads or membranes to physically remove particles. Most UK producers use both, in a defined sequence: a light fining, then a coarse filtration, sometimes followed by a finer polish filtration just before bottling.

Excessive filtration can strip a wine of aroma and body. The art is to filter enough to make the wine stable, but not so much that it loses its character. The choice depends on the wine's style, the target market and the producer's house philosophy.