Wet dog? Barnyard smell? Pickled cabbage? Rotten apples? Vinegar? Glue? Mold? Nobody likes such attributes in their wine tasting notes. Unfortunately, sometimes even if manufacturers, distributors, and even consumers try their best, the wine ending up in our glasses has one of these defects. What is the best solution? Can we avoid these situations?
Can we identify bottles of flawed wines, or do we always play Russian roulette with our senses?
How severe are these flaws? Do they endanger our health or just our good mood? Can they be removed or the only solution is … another bottle?
Compared to other industries, the wine business has a failure rate a couple of thousand times higher. For example, while 3-4 defects per million are acceptable in car production, in the case of wine, cork taint is considered normal in 2-5% of the cases, i.e., up to 50,000 bottles affected in one million. As consumers, it is essential to know this, so we do not necessarily blame the manufacturer, sometimes it is just how the industry works.
How do we define wine flaws?
In the case of certain severe defects of the wine, a consensus has been reached. For example, no one appreciates the smell of cooked cabbage, onion or garlic in a glass.
However, there are situations when consumers or even specialists believe that wines that could be classified as flawed are, in fact, attractive, either due to the wine-making style or by exploiting a particular philosophy. This category includes slightly oxidized wines that get notes of cooked apple, almonds or nuts. Another situation is that of red wines, especially Bordeaux-style blends that get a hint of barnyard or tanned leather due to wild yeasts. In this case, intensity makes the difference between defects and character.
Classification of wine defects by cause
From the vineyard to the glass, wine can is exposed to various factors that affect its quality. The most dangerous categories of flaws include oxidation, the opposite, reductive processes that are related to sulfur and, last but not least, the influence of microorganisms. On top of all these comes the human negligence, manifested most often as improper storage conditions or the lack of hygiene in the cellar.
During the production, aging, bottling and storage processes, the wine must be protected from coming in contact with air. Otherwise, the fast degradation process begins. Oxidized wines change color, the whites become golden, while the reds get tawny hues. The taste becomes flatter; the alcohol content is lower and overall, the wine begins to lack fruitiness and freshness. In the nose, there are intense notes of rotten apples, walnuts, almonds due to the formation of the acetaldehyde. This substance is dangerous since it gives severe headaches the next day.
A more advanced stage of oxidation is the smell of vinegar which is due to bacteria that consume alcohol. Prevention in the wine cellar means filling the containers with either wine or inert gas. Although all wines contain a small percentage of vinegar, when it becomes perceptible in the nose (“volatile acidity”), it means that the wine is already on a descending trend. In extreme cases, oxidation goes further and volatile acidity increases. In these cases, the wine smells like in solvents (e.g., glue, nail polish) or even soap.
Since historically certain wines, such as the Spanish sherry, have deliberately included oxidation in the production process, it is time to make the difference between oxidized wines and oxidative wines. Oxidative wines contain the notes of candied fruits, nuts, almonds, and bruised apples, but in proportions that give flavor. These wines are usually fortified and have a significant alcoholic content (15-17%), which provides balance.
In Romania, there is a long legacy of oxidized wines on the market. Some consumers, usually the older ones, consider this flaw to be worthy of appreciation. The bad news is that oxidized wines cannot be saved.
To prevent oxidation, oenologists use sulfur dioxide (SO2), also known as E220. Chemically, reduction is the opposite of oxidation. Defects of this type occur when sulphuric components are used excessively in wines, and the odors associated with these compounds become evident to the consumer, especially in whites. Moreover, an excess of sulfur dioxide can cause severe migraines.
Enologists are responsible for exact math in terms of SO2. Too little SO2 and the wine can oxidize or referment in the bottle, too much leads to an unpleasant experience, smelling like rotten eggs. If it is added too early, when the wine is still under fermentation, it can turn into hydrogen sulfide that smells like sewage or burned rubber. Sometimes the sulfur present in the wine is due to the insecticides and fungicides used in the vineyard and not to the subsequent addition, but the effects are similar.
There is an international trend to reduce the amount of sulfur present in wine, following the principle of minimal interventions, especially in the case of organic wines. To achieve this classification, there are strict international regulations.
When the presence of sulfur is excessive, mercaptans that give onion taste or other compounds that remind of boiled cauliflower appear. In these situations, wine is unpleasant, and consumption is not recommended. These advanced degradation stages are often due to defective storing by excessive exposure to UV light, as is the case with wines kept too far on shelves in the supermarket.
If the wine has only a hint of sulfur, it can be aerated or decanted, most often regaining its pleasant and fruity nature. Another method of removing sulfur compounds is to dip a copper coin or a silver spoon into the glass.
Perhaps the most common and upsetting flaw is the “cork taint”. It imparts the wine’s taste and smell with odors of wet cardboard, newspapers, stagnant water or wet dog and leads to the loss of freshness or fruity nature.
It is mainly due to TCA (2,4,6-trichloroanisole), but also to TBA (2,4,6-tribromoanisole). TCA occurs due to specific fungus present in wood treated with chlorinated compounds during processing. Sometimes TCA infects whole segments of the production line or even the entire cellar; it is challenging to remove.
The affected bottles cannot be saved in any way, requiring replacement of the product. Professor Waterhouse from the University of California suggests that wine can be improved by pouring it into a glass in which a food film is placed, as the TCA molecule tends to cling to the plastic.
Hygiene in the wine cellar is the most crucial aspect to produce quality wine. If we find a wine with a moldy or rotten odor, it is a clear indication that the barrels or other equipment have colonies of unwanted microorganisms and the wine should not be consumed.
A particular case is when we are dealing with a wine with complex flavors ranging from matured cheese to animal scents (barnyard or horse sweat). These flavors are caused by wild yeasts called Brettanomyces or simply, Brett. Depending on the Brett concentration, the affected wine can be described as enriched or be deemed unpalatable. Not all connoisseurs believe Brett is a defect; many even appreciate such flavors in robust red wines, such as Bordeaux, considering that they become more gastronomic and more expressive.
Good manners at the restaurant
In conclusion, it is important to note that the reason waiters offer the customer the wine for tasting and even the cork for inspection is to determine if there are any flaws. If one of the defects is identified, the client can always refuse the bottle. It is the role of the sommelier to explain to the client the possible style particularities that could be considered flaws and to ensure that the client’s preferences are fit for the chosen wine.
Parts of this material were presented at the “Wine defects – Les Fleurs du Mal” masterclass, which took place on March 9th at Vin la Braşov.
Behind the keyboard...
Silvia Palasca- web dev by day, wine storyteller by night (or the other way around)
Hello, I'm Silvia, wine and travel enthusiast. Looking to turn my passions into a lifestyle. As I writer and web designer I thrive on great sips and epic scenery. WSET Level 2 graduate, I love writing, talking and analyzing wine. If you have a project in mind, let's talk!