Fining

Fining is a winemaking technique used to clarify and stabilize wine by adding fining agents that bind with undesirable suspended solids, pigments, tannins, or proteins. The resulting complexes are heavier and settle to the bottom of the vessel or can be removed by filtration, leaving the wine clearer and more stable.

Common fining agents include gelatin, isinglass (fish bladder collagen), egg white (albumin), casein (milk protein), bentonite (a clay), PVPP (polyvinylpolypyrrolidone), and activated charcoal. Gelatin and isinglass help remove tannins and pigments; egg white and casein are often used to soften tannins and pale color in red wines; bentonite targets proteins to prevent hazes; PVPP adsorbs phenolics; activated charcoal can reduce certain off-flavors or colors. Some producers also use enzymes or synthetic polymers as fining aids.

The agent is typically added to the wine, mixed, and allowed to interact with target substances so they precipitate or adhere to the fining material, after which the wine is racked or filtered to remove the settled material. Fining can be performed during fermentation, after fermentation, or during aging, depending on the wine and goals. Because fining can remove or alter aroma, flavor compounds, or mouthfeel, winemakers choose agents carefully. Allergen considerations exist for agents derived from egg, milk, or fish, and labeling requirements vary by jurisdiction.

Alternatives to fining include filtration, cold stabilization, or timed aging to achieve clarity and stability. Fining remains a common, traditional tool for balancing appearance, stability, and style in wine.