Collective name for defects or undesirable and unacceptable errors in wine, which are mainly unpleasant or disgusting odor and or taste or "only" in appearance (veil, opacities, Crystals, etc.). Among other things, you will be at a wine review and wine address determined, with certain errors or a certain extent such wines then fall out of the rating. Sometimes a distinction is made between wine defects (wine defects) and wine diseases. Second ones are through microorganisms ( bacteria. mushrooms. virus ) induced changes in the wine, which can increase in intensity if appropriate countermeasures are not taken.
In a few cases, it is subjective whether a certain smell and taste is positive or already perceived as an error. Because there are some borderline cases where a certain smell or taste is pleasant and positive for some, but unpleasant to flawed for others. Examples of this are typical petrol tone a Riesling or the earthy Smell and than horse sweat designated tone of a red wine. In addition, there are objectively ascertainable general defects that deviate from a certain standard. The spectrum ranges from barely or barely perceptible to unpleasant and spoiled and also depends on experience and sensitivity. A notable example is the notorious one corked, which is recognized by practiced people with the slightest expression. With appropriate experience, wine errors can be identified or identified quite precisely. You can also learn this, various manufacturers offer flavor sets for this:
Most of the time, however sensory Assessment insufficient for precise identification. The causes of wine defects can occur during the growth of the grapes and then during the entire processing chain from the vintage to the bottling, but also afterwards during the bottle aging occur. Mostly it is chemical and microbiological processes that are caused by microorganisms such as mushrooms or bacteria triggered or complex reactions of different substances. Causes can also be physical, such as too much contact with oxygen his.
The smell and taste of a wine is made up of many chemical compounds. The total extract is between 17 and 30 g / l for a quality wine. They do that flavorings 0.8 to 1.2 g / l. With almost all wine defects, the causative substances are now known. These mostly extremely small quantities are given in milligrams (mg = thousandths), micrograms (µg = millionths) to nanograms (ng = billionths) per liter. In the latter, this means a single grain of wheat of ten tons of wheat. They are perceived from a certain amount, which is called the perception threshold: