Defects in Wine

Affecting the taste and odor

Some minor changes in the condition of a wine are of a nature that will not detract from the aroma or flavor. The most common example is the precipitation of tart rates, yeasts or coloring substances, which form sediment in the bottom of the bottle. More serious defects due to contamination alter the taste and odor.

The most common defects which alter a wine are:

• Taste/smell of cork: a moldy smell of mushrooms or damp earth caused by corks made from raw material infected by a parasitic fungus, Armillaria Mellea. Another source of contamination is a mould, which can form under the corks of bottles left standing upright and which has a smell reminiscent of wet cardboard. It can be avoided by storing bottles horizontally so the wine is always in contact with the bottom of the cork.
• Taste/smell of dry wood: is the result of the neglect of barrel hygiene. Left empty without cleaning with sulphur, barrels may transmit odors of dry wood and astringent flavors to wine aged in them.
• Smell of Sulphur: an acrid odor similar to that of a struck match, caused by the excessive use of Sulphur dioxide. Also leaves a bitter, prickly sensation at the back of the throat.
• Oxidation: is a serious defect, which mainly affects dry white wines. Also known as maderization. Oxidized wines have an unhealthy dark and lifeless color and an unpleasant odor like burnt caramel.