Using Fining Agents (WineMaker)

White wine in glasses

Pesky cloudy wines!

Sediments in the bottle! There is nothing more frustrating to home winemakers than a wine that will not clear or that continues to throw sediments in the bottle.

Making crystal-clear wine is an important objective in any type of winemaking. Anything less is considered a serious wine fault — a telltale sign of poor winemaking control — and will probably be shunned by serious wine drinkers.

A seemingly clear wine can also throw sediments in the bottle. This is usually not considered a wine fault in older wines that have been aged for many years and that have not been clarified except for periodical rackings. However, sediments in early-drinking, young wines are a sign of insufficient clarification and rushed winemaking.

Grape juice and wine contain many naturally occurring particles as well as compounds acquired during winemaking, such as tannins during oak barrel aging, which will affect clarity and may result in sediments in the bottle. Proteins, pectins, phenols (such as color pigments, tannins) and salts are examples of such particles that need to be controlled through racking, use of natural additives (fining agents), and careful filtration.

Note: Clear (tartrate) crystal deposits at the bottom of a bottle or on the inside end of the cork are a result of the wine being subjected to cold temperatures. Tartrate crystals are a different beast altogether and should not be confused with other sorts of sediment. Tartaric acid, the most prominent wine acid, will cause some precipitation under cold temperatures; it is not a problem related to clarification. Cold stabilizing the wine prior to bottling prevents tartrate deposits. (Refer to “Fix Your Wine!” in the Winter 2001 issue of WineMaker for more information on cold stabilization.)

Many traditional commercial wine-makers, many of whom produce some of the best wines in the world, avoid the use of additives or filtration to clarify wine for fear it might be perceived as unnatural. These winemakers prefer to rely on periodical rackings, i.e., they rack every 3 months over a period of 18–24 months.

Home winemakers wanting to produce early-drinking wines without the hassle of multiple rackings or having to age wine should always clarify wine using fining agents and/or filtration. In this article, we will examine fining agents available to home winemakers, and explain how to maximize their effectiveness in clarifying wines.

Selecting and using fining agents

Early-drinking wines from fresh juice or grapes should always be clarified prior to bottling. The high-protein content in these wines can cause clarity instability, resulting in a cloudy wine or sediments in the bottle. Wines from concentrate or other processed juice (such as semi-concentrate or sterilized juice) are designed for quick production and bottling and therefore should also be clarified.

When selecting a fining agent, the main factors to consider are the type of wine you are making (white or red), the tannin concentration of the wine, and desired results relative to color.

Fining agents have varying levels of effectiveness in white versus red wines because of different particles present, namely concentration of phenolic compounds. Tannin concentration is the most significant difference in the context of clarification and may cause improper clarification with some fining agents, resulting in a cloudy wine or bottle sedimentation. Grapes and the process used in red winemaking impart a higher concentration of phenolic compounds. As a result, red wines have a significantly higher tannin content compared to white wines. Wines aged in oak barrels will also have higher tannin content because oak is rich in tannin.

The primary objective of clarification using fining agents is to produce a clear wine, free of suspended particles that could otherwise affect clarity. Color should be altered only minimally, except in the case where color must be corrected from such problems as browning due to oxidation. Great care must be taken with some fining agents to avoid over-fining, which would strip color compounds from the wine.

The table above lists common, commercially available fining agents for clarifying white and red wines, along with the recommended rate of addition and the type of wine where it is most effective, and other products used to improve the effectiveness of fining agents. Always start with the lowest rate of addition in the recommended ranges, and increase the rate, as required, if the wine requires further clarification.

Fining agents in solid form should always be dissolved in water first, unless specified otherwise, according to instructions before adding to wine. Fining agents lose their effectiveness if dissolved or introduced directly into the wine.

Fining agents detailed below include bentonite, casein, egg whites, gelatin, isinglass, kieselsol, pectic enzymes, pvpp, sparkolloid, and tannin.

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