Fining Agent

Definition - What does Fining Agent mean?

A Fining Agent is a substance used during the Fining or clarification stage of winemaking. It is added to the wines in order to bond with the soluble substances that cause cloudiness, haze or could cause wine faults in a wine.

The theory behind fining agents is that the soluble substances have a specific electric charge (positive or negative); therefore, each fining agent has an opposite charge in order to allow them to bond with the unwanted particles. Positively charged fining agents include gelatin, egg albumen, isinglass and sparkalloid; negatively charged fining agents include bentonite and kieselsol.

WineFrog explains Fining Agent

There are many types of fining agents, each used to target a specific "fault" in the wine or used in order to abide by a certain code (vegan wine, no added chemicals, etc.). They can come in liquid, powder or solid form; some, like Bentonite, proteins and polysaccharides must be prepared for use while others can just be tossed into the wine.

There are two main types of Fining Agents: organic compounds and solid/mineral materials. These two categories are then divided into sub-categories.

Organic Compounds
Proteins
Casein - derived from milk; used in white wines to remove undesirable odors, bleach color and clarify

Isinglass - derived from fish bladders; gentle alternative to gelatin usually used on white wines to clarify

Egg albumen - derived from egg whites; most commonly used to reduce harsh tannins in red wines

Gelatin
Clarifies overly astringent wines; used in conjunction with Kieselsol.

Solid/Mineral Materials
Earth
Bentontine Clay - effective in absorbing proteins and some bacteria

Sparkolloid - used to clarify wines after fining is complete

Carbons (from charcoal)
Activated carbons - removes some phenols that contribute to browning as well as some particles that produce "off-odors" in the wine.

Silica & Synthetic Compounds
Kieselsol - used in conjunction with gelatin in white wines for clarification and tannin reduction

Polyvinyl polypyrrolidone (PVPP) - used to remove bitter and browning compounds in red and white wines

Other possible fining agents include Kaolin, Carrageenan, copper sulfate, hydrated yeast, Alginate, Chitin, Gum Arabic and Pectin destroying enzymes.