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Faults and Troubleshooting

Asparagus - Overripe grapes, wine kept too long in bottle. Fix - there isn’t a technical fault in this case. Buy a more current vintage next time.Banana - Caused by malolactic fermentation. Can be pleasant when subtle, but tastes odd in larger amounts especially in red wines. Leads to a nail polish aroma.
Fix - Not a fault, but not a good thing either. Make Sangria promptly.

Band-Aid - Indicates the presence of brettanomyces
Fix - If the odor doesn’t go away after several minutes, there isn’t a cure.

Burning Match/Sulfur - Caused by excesses of sulfur dioxide. All wines have sulfites, but too much can be unpleasant.
Fix - Swirling the glass or decanting removes the odor.

Cork - Bits of cork floating in bottle
Fix - If the wine itself is not spoiled, fish them out and drink up! It was your fault.

Corked - Indicated by a musty or moldy odor and taste. This is a common, naturally occurring wine fault. It is usually caused by exposing chlorine-soaked corks to warm, moist conditions, allowing the formation of a chemical called 2-4-6 Trichloroanisole, or TCA.
Fix - if the wine is truly corked, it will worsen, in which case there is no cure.

Crystals (tartrates) - Tartrates are harmless crystalline deposits that form during fermentation or aging. These crystals are made up of tartaric acids that are less soluble in wine than in water or juice. Many wineries remove these compounds with a process called cold stabilization.
Fix - straining the wine is the easiest way to remove these harmless crystals.

Dilute wine - A watery, weak taste in wine. The winemaker allowed the yields from his vineyards to grow unacceptably high; or that it rained just before or during the harvest, so that the grapes were literally diluted with rainwater.
Fix - Drink it as quickly as possible or cook with it.

Dirty Socks - Result of many problems, can be unclean barrels or bacterial contamination.
Fix - There isn’t a cure.

Film/Oily Slick on Surface - Improperly washed glasses.
Fix - Use detergent and rinse thoroughly in warm water. Don’t use glass-drying cloths for anything else.

Hard-Boiled/Rotten Egg- An odor caused when sulphur attaches to hydrogen, creating hydrogen sulphide.
Fix - If you have the patience, you could place a brass or copper object in the wine, and the odor should precipitate out as a fine sediment.

Barnyard aroma can be a sign of a wine-spoiling yeast

Horse Blanket/Manure - Sign of Brettanomyces, a wine-spoiling yeast.

Maderization - Certainly acceptable in Madeira and Vins doux naturels. In most wines, however, this is a fault where wine is allowed to become oxidized and is exposed to warm temperatures, acquiring a cooked toffee-like flavor with some browning of the wine.
Fix - There isn’t a cure.

Margarine - Excessive amounts of diacetyl, the buttery compound formed during the primary fermentation.
Fix - Spread the wine on toast.

Moldy Odors - Bacterial spoilage, moldy grapes, or unclean barrels can cause this.
Fix - There isn’t a cure.

Musty Odors - Caused either by unclean barrels or corkiness in the wine.
Fix- There isn’t a cure.

Nail Polish - Produced by intensive carbonic maceration, found in the worst Beaujolais Nouveau, is also known as banana oil or pear oil.
Fix - Don’t be so cheap next time.

Onion/Garlic/Burnt Rubber - A serious fault caused by the reaction of alcohol to hydrogen sulphide, another wine fault, to create a foul-smelling compound called ethylmercaptain.
Fix - There isn’t a cure.

Re-fermentation/bubbles - Unless the wine is labeled as a sparkling wine, this is a bad thing (some exceptions include Freisa, Brachetto, Moscato d’Asti, etc.). It is caused when unspent yeast that has not been removed reacts with residual sugar and ferments for a second time, trapping gasses in the bottle.
Fix - if the problem is minimal, use a vacu-vin to remove the gas.

Rubbing Alcohol - The wine’s alcohol level is out of balance. Apply to wounds to prevent infection.

Sauerkraut - Lactic smell of excessive malolactic fermentation. Even worse in wine than sour milk or sour cream aromas.
Fix - There isn’t a cure.

Sediment - Non-soluble deposits consisting of crystalline and phenolic compounds precipitate from the bottled wine over time. This is harmless and normal, though sediment is not pleasant to drink.
Fix- Decant or strain the bottle.

Sherry-like aromas - Excessive acetaldehyde, which turns wines into vinegar. Sherry itself is protected from acetaldehyde by high alcohol levels which prevent spoilage.
Fix - There isn’t a cure.

A wet dog aroma is asure sign the wine is corked.

Skunky - A sign of mercaptain compounds, which are terrible smelling sulphur compounds that are created when hydrogen sulphide and other basic sulphur compounds combine to create an even worse problem.
Fix - There isn’t a cure.

Vinegar - A sign of acetic acid bacteria, formed when fermentation is not handled correctly. Combination of alcohol, oxygen, and acetic acid bacteria.