Wine fault

Wine fault or wine defect is an undesirable characteristic of wine often resulting from poor winemaking practices or storage conditions, and leading to wine spoilage. Many of the compounds that cause wine faults are already naturally present in wine but at insufficient concentrations to adversely affect it. However, when the concentration of these compounds greatly exceeds the sensory threshold, they replace or obscure the flavors and aromas that the wine should be expressing (or that the winemaker wants the wine to express). Ultimately, the quality of the wine is reduced, making it less appealing and sometimes undrinkable.

Types of Wine Faults

There are many types of wine faults. Some of the most common include:

• Oxidation: This is the most common wine fault, and is usually the result of extended exposure to oxygen. Oxidation can occur at any stage of winemaking, from grape to bottle. The effects of oxidation can include a loss of color, the development of nutty flavors, and a decrease in fruitiness.

• Cork taint: This is a broad term referring to a wine fault characterized by a set of undesirable smells or tastes found in a bottle of wine, especially spoilage that can only be detected after bottling, aging and opening. Though modern studies have shown that other factors can also be a source of taint, including wooden barrels, storage conditions and the transport of corks and wine.

• Volatile acidity: This is a wine fault most commonly caused by bacterial spoilage. The most common cause of volatile acidity is the presence of acetic acid bacteria, which produce acetic acid (the main component of vinegar) as a byproduct of fermentation.

• Reduction: This is a wine fault that occurs when a wine has not been exposed to enough oxygen and develops a reductive, or "stinky", aroma. This can be caused by a number of factors, including poor winemaking practices and the use of certain types of closures.

• Brettanomyces: This is a type of yeast that can, in small amounts, add complexity to a wine. However, if present in large amounts, it can overpower the wine, producing off-flavors and aromas.

Prevention and Treatment

Prevention and treatment of wine faults is a complex and important aspect of winemaking. The first step in preventing wine faults is to ensure clean and sanitary winemaking practices. This includes the proper cleaning and sanitizing of all winemaking equipment and facilities. Additionally, careful monitoring of the fermentation process can help to prevent many common wine faults.

In terms of treatment, options vary depending on the specific fault. For example, oxidation can be prevented through the use of antioxidants like sulfur dioxide. Cork taint can be prevented by using high quality corks and ensuring proper storage conditions. Volatile acidity can be treated by using specific types of yeast during fermentation. Reduction can be prevented by ensuring the wine is exposed to sufficient oxygen during the winemaking process. Brettanomyces can be controlled through careful sanitation practices and the use of specific types of yeast.

See Also

• Winemaking
• Wine tasting
• Wine chemistry
• Sommelier

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