When Wines Go Bad

It doesn’t matter if you make wine at home, in a commercial setting, or enjoy drinking it; there’s a good chance you’ve encountered wine with faults. Perhaps it was the subtle scent of geranium leaf, an aromatically soft glass pour, or the distinctive smell of a barnyard, or maybe you thought you’d poured yourself the perfect drink of nail polish remover, but you made an accident. Whatever the reason, it is important to recognize that wines exhibit flaws due to a variety of reasons, which are each a sign of something going wrong in the cellar, vineyard transport, or storage period, is crucial to better understanding of the process of making wine.

There are a myriad of books and articles devoted to investigating these issues thoroughly, which is the reason this article serves as a simple, practical guide when you are looking for a basic description of the most commonly encountered errors.

Before we dive into the subject of our investigation, we must first know the distinction between the two terms fault and a flaw and a. A wine can exhibit a variety of imperfections when, at a certain stage in the process of making wine, something was (or wasn’t) accomplished that results in the final product having an attribute that is not appropriate for the style or variety. The flaws in wine are not major issues but the wine might still be perfectly acceptable, and perhaps even enjoyable. The flaws could be visible (tartrate crystals sediment, haze tiny carbonation in a wine that is not sparkling wine) and also aromatic (volatile acidity sulfur dioxide Brettanomyces absence ofaroma that is not varietal and decreased sulfur compounds in low amounts diacetyl, excessive oaking) as well as flaws in taste (searing acidity, unintentionally sweet excessively high or unusually low levels of alcohol).

There isn’t a definitive moment when a flaw is an issue, but there are established thresholds that have been studied, the moment at which we can recognize that a wine’s fault is clearly identifiable and/or overwhelming of any other characteristic of the wine. Simply put, a wine that is faulted is a wine that has been contaminated and has reached extremely high levels. If a wine completely loses its uniqueness and the flaw emerges as the only characteristic that makes it stand out, covering the other aromas or taste, the wine is considered to be inedible at this stage. We will focus on the top prevalent errors you could be confronted with when crafting your own bottle of wine. A lot of them can be caused by co-creation or the same root issues; however, for the purpose of better understanding the root cause, each of them is listed separately.


While it is sometimes a deliberate and aesthetic decision (such for example, in the making of Sherry that has “oxidative characteristics”), the process of oxidation happens when wine and oxygen come into contact to produce recognizable aromas of oxidation by altering the chemical structure of wine. Oxidation doesn’t affect all wines in the same way. For instance, very aromatic white wines will suffer the effects resulting from oxidation much more quickly and clearly than phenolic heavy, tannic red wines. Wines can be oxidized in the process of or following bottle-bottled.

Sensitivity threshold Very variable, and dependent on wine style. The distinction between “oxidative characteristics” and “oxidized wine” is an issue of personal taste.

The reason: Excessive oxygen exposure following fermentation, prolonged maceration period due to inadequate use of inert gas Insufficient oxygen-free sulfur dioxide (SO 2) and bottling using faulty corks.

Identification: Diminished flavor and scent. A smoky aroma of stewed fruit like prune, walnut and fennel. Hay, Sherry-like. Red wines turn brick red/brown in hue (particularly evident in young wine that started with vibrant violet and red hues) while white wines develop a dark golden hue.

A brownish hue.

Preventive: Sufficient use of inert gas, SO 2, refrigeration, high-quality corks, and old bottles to stop the cork from drying. Corks of high quality are essential, as is long-term storage in an area that is cool and dark because heat speeds up the process of oxidation, and low humidity can cause the cork to dry.

Repair: Cannot be remedied. Prevention is the key to success.


Acetaldehyde results from the oxidation of alcohol. It is produced by acetic acid bacteria under low oxygen levels, high alcohol conditions. It is also possible for yeasts to transform ethanol into acetaldehyde when in an oxidative environment.

The threshold for sensorial perception is 100 to 125 mg/L. Lower concentrations (70 mg/L) may give fruity scents while greater levels (100plus mg/L) can be considered undesirable.

The reason: Film yeasts or Acetobacter in an environment that is oxidative, with low So 2 levels, high headspace, defective corks the addition of excessive amounts of SO 2 during fermentation, high pH and allowing fermentation temperatures to reach a high temperature.

Detected: Overall loss of characteristic characteristics of the varietal. Aromas of bruised or overripe apple, dry, vegetal straw roasting nuts, almonds and Sherry-like characteristics. The high concentrations of these wines display the metallic, sour taste. White wines acquire deeper brown or golden colors, while reds take on the brick red hue.

Protection: Top up barrels to reduce headspace. Be aware that a rise in the temperature of fermentation, pH as well as adding SO 2 in the course of fermentation can raise the level of acetaldehyde. Minimize wine’s exposure to oxygen after fermentation. Keep the proper levels of SO-free 2. levels.

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