What are common fining agents for wine?

• A. Bentonite (clay), egg whites, isinglass.
• B. Gelatin only.
• C. Charcoal filtrate.
• D. Pectin enzymes.

Answer: (A)

Fining agents are substances added to wine to bind unwanted particles—like haze-forming proteins, tannins, or phenolics—so they can be removed and the wine clarifies without losing aroma or flavor. Bentonite is a negatively charged clay that binds positively charged proteins, helping prevent protein hazes and stabilizing white wines and other wines prone to instability. Egg whites (albumin) supply proteins that attach to tannins and phenolics, which is especially helpful for softening astringency in red wines and aiding clarity. Isinglass, a collagen from fish bladder, acts similarly by binding particles to clarify the wine, often used to fine white wines without stripping aroma.

These three are among the most common and versatile fining options because they target different components (proteins, tannins/phenolics) and work well with minimal impact on aroma and flavor when used appropriately. Other choices mentioned—gelatin—exists as a fining option but is not the only one, so saying “gelatin only” isn’t accurate. Charcoal-based treatment is more about decolorization and adsorption during filtration rather than fining, and pectin enzymes are used to improve filtration by breaking down pectin rather than to bind and remove haze-forming particles.