Collective term for defects or unwanted and unacceptable defects in wine, which are mainly due to unpleasant to disgusting odor and or taste or even "only" in appearance (veil, opacities, Crystals etc.). You will be among others at one wine review and wine address determined, then fall for certain errors or a certain extent such wines from the rating. Sometimes a distinction is made between wine defects (wine defects) and wine diseases. The second are through microorganisms ( bacteria. mushrooms. virus ), which may increase in intensity if appropriate countermeasures are not taken.
Whether a certain smell and taste is perceived positively or already as a mistake is subjective in a few cases. Because there are some borderline cases, where a certain smell or taste for one pleasant and positive, for the other, however, is unpleasant or faulty. Examples are the typical ones petrol tone a Riesling or the earthy Smell and as horse sweat designated tone of a red wine. In addition, there are objectively detectable general defects that deviate from a certain standard. The range goes from barely perceptible to uncomfortable and corrupt and also depends on experience and sensitivity. A good example is the notorious one corked, which is recognized by experienced persons even at the lowest level. With appropriate experience one can recognize or identify wine mistakes quite exactly. You can also learn this, and various manufacturers offer aroma sets for this:
Mostly, however, is the sensory Assessment for exact identification is not sufficient. The causes of wine defects can be found as early as the growth of the grapes, and then throughout the whole chain of production, from the vintage to the first bottling, but also later during the bottle aging occur. Most of them are chemical and microbiological processes caused by microorganisms such as mushrooms or bacteria be triggered or complex reactions of different substances. Causes can also be physical in nature, such as too much contact with oxygen be.
The smell and taste of a wine is composed of many chemical compounds. Of 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 off. Almost all wine defects meanwhile know the causative substances. These mostly extremely small amounts are given in milligrams (mg = thousandths), micrograms (μg = millionths) to nanograms (ng = billionths) per liter. In the latter case, this means a single wheat grain of ten tons of wheat. They are perceived from a certain amount, called the perceptual threshold: