Wine fault: Encyclopedia - Wine fault

Wine fault

A wine fault or defect is an unpleasant characteristic of a wine resulting from poor winemaking or storage. Faults can be loosely grouped into three main categories:

Wine fault - Oxidation

Oxygen plays a critical role in the production and aging of wine, but its interaction with it must be carefully managed. The following by-products of fermentation and their characteristic aromas are always present in well-made wines—and are responsible for pleasant aromas in low quantities—but are considered defects at sufficiently high enough concentrations to be apparent.

• Acetaldehyde — rotten apples, sherry
• Acetic acid — vinegar
• Ethyl acetate — nail polish remover, glue, or varnish

Wine fault - Sulfur

Sulfur is also used throughout the winemaking process, primarily to stop oxidation and fermentation. Common faults include:

• Sulfur dioxide — matchsticks
• Hydrogen sulfide — rotten eggs
• Mercaptans — onion, rubber, skunk

Wine fault - Fungus / Yeast

Defects caused by fungus or bacteria are usually the result of improper storage of the wine. They include:

• Cork taint — cardboard, wet dog
• Brettanomyces — horse saddle, band-aids
• Refermentation — coarse or funky aromas, slight carbonation

Adapted from the Wikipedia article "Wine fault", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki