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Wine faults

winefault (GB)
difetto del vino (I)
défault d’un vin (F)
defeito de vinho (PO)
defecto de vino (ES)

Collective term for defects or undesirable and unacceptable faults in the wine, which are expressed mainly by unpleasant to disgusting smell and/or taste or "only" in appearance (haze, turbidity, crystals, etc.). They are determined, among other things, during a wine evaluation and wine appeal, whereby such wines then fall out of the evaluation in the case of certain faults or to a certain extent. Sometimes a distinction is made between wine faults (wine defects) and wine diseases. The latter are changes in wine caused by micro-organisms(bacteria, fungi, viruses), which can increase in intensity if appropriate countermeasures are not taken.

Nagellack-Ton, Schimmel-Geschmack, Böckser, Korker

Whether a certain smell and taste is already perceived as a fault is subjective in some cases. For there are some borderline cases where a certain smell or taste is pleasant and positive for one person, but unpleasant or even faulty for another. Examples of this are the typical petroleum tone of a Riesling or the earthy smell and tone of a red wine known as horse sweat. In addition, however, there are objectively identifiable general defects that deviate from a specific standard. They range from barely or weakly perceptible to unpleasant and spoiled and also depend on experience and sensitivity. A good example is the notorious cork taster, which can be recognized by trained persons even at the slightest degree. With appropriate experience, wine faults can be detected or identified quite accurately. This can also be learned, various manufacturers offer aroma sets for this:

Aromaset Weinfehler

In most cases, however, sensory evaluation is not sufficient for accurate identification. The causes of wine defects can occur already during the growth of the grapes and then during the entire processing chain from harvesting to bottling, but also afterwards during bottle ripening. In most cases, they are chemical and microbiological processes triggered by microorganisms such as fungi or bacteria or complex reactions of various substances. Causes can also be of a physical nature, such as too much contact with oxygen.

causative substances

The smell and taste of a wine is composed of many chemical compounds. The total extract of a quality wine is between 17 and 30 g/l. Of this, the aromatic substances account for 0.8 to 1.2 g/l. For almost all wine faults, the substances causing them are now known. These mostly extremely small quantities are indicated in milligrams (mg = thousandth), micrograms (µg = millionth) to nanograms (ng = billionth) per litre. For the latter, this means a single grain of ten tons of wheat. They are perceived from a certain amount, which is called the perception threshold:

Wine faults Substance Quantity
Bitter almond tone Prussic acid 0.04 mg
Strawberry Flavour Furaneol 30 to 40 ng
Foxton Aminoacetophenone 0,5 µg
Cork taster Methoxy-dimethylpyrazine
Tribromanisole (TBA)
Trichloroanisole (TCA)
2 to 4 ng
3 to 4 ng
1 to 5 ng
Mice Acetic acid ethyl ester and others 0,1 to 1,6 µg
Horse sweat Etyhylcatechol (horse stable, sweat)
Ethylguajacol(cloves, tar)
Ethylphenol (medical grade)
50 µg
50 µg
300 to 600 µg
Black fracture, metallic Iron
10 mg
2 mg
5 mg
UTA (atypical age tone) Aminoacetophenone 0,5 µg

The wine defects or substances causing defects can only be determined beyond doubt by analytical methods. One of these methods is chromatography (gas chromatography). A new method for the detection of microbiologically caused wine defects is PNA-FISH (Peptide Nucleic Acid Fluorescence In Situ Hybridisation). Most important in wine production is absolute cleanliness and sterility and (usually) avoidance of oxidation (oxygen access). If these measures, some of which are quite complex, are observed, many wine faults can be avoided.


The list contains not only wine faults but also related terms:

Literature and sources

Three particularly recommendable books on this complex subject area, which have also been used as sources with the kind permission of the publishers/authors

Wine faults - recognition, avoidance, correction
Österreichischer Agrarverlag Druck- und Verlags Ges.m.b.H. Nfg.KG, Leopoldsdorf
Dipl.-Ing. Dr. Reinhard Eder (editorial management) et al.

Recognizing wine faults - determining, avoiding, remedy
Eugen Ulmer KG 2007 / Dr. Edmund Lemperle

Wine cellar management
Austrian agricultural publishing house - 2001 Leopoldsdorf
HR Dipl.-Ing. Robert Steidl Department of Wine Cellar Management / Dept. of Enology
Federal College and Federal Office for Wine and Fruit Growing Klosterneuburg Lower Austria

Nail polish: Picture from donations welcome on Pixabay
Grape: From Robert Owen election on Pixabay
Böckser: From Capri23auto on Pixabay
Corker: From 445693 on Pixabay
Wine defect set: © www.aromaster.com

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