One of the more difficult things to recognize in wine is faults. We can usually say “This wine does not taste right”, but few of us can explain why it does not. So, the question remains, is your wine flawed or not? Is it the taste of old-world wine or new-world wine, incorrect storage problems or your taster? Wine is made of four elements: water, alcohol, acidity and phenolic compounds which makes wine a living thing. The process of aging wine will give wine complexity and maybe some faults. The most common wine faults are corked, over-the-hill, oxidation, cooked, Brett (Brettanomyces’s), VA (volatile acidity) and reduction.
We will look briefly at these seven faults.
1. Corked Wine
Corked wine is a wine fault that will make the wine smell like a damp moldy basement, a wet dog, musty cardboard or a wet newspaper. The wine will have a muted fruit flavor and will be dull (a lack of fruit flavor) caused by TCA. TCA stands for 2,4,6-trichchloroanisole and is a powerful chemical behind corked wine. Just a small amount causes the musty flavors and aromas in wine. The 3 compounds of TCA are plant phenols, chlorine and mold. TCA does not occur naturally and is caused by a fungus. Corked wine usually occurs from the natural cork and TCA is transferred to wine. The other sources of corked wine are caused by the winery from damp surfaces, barrels, wooden pallets or chlorine-based cleaning products. TCA is not a health problem but spoils the taste of the wine. There is no legal standard for levels of TCA in wines and according to studies, approximately 1 to 3% of wine is tainted by TCA.
Wine eventually dies and will develop a taste of prunes and cooked fruit. One of the big misconceptions regarding wine is it improves with age, yet about 90% of wine that is produced is to be enjoyed at a younger date. Most wines are not produced to age more than a few years. However, there is no formula for calculating when a wine should be consumed, because there are too many variables in wine. So, don’t save your wine forever with the biggest aging factor being storage conditions. Aged wine will soften and become more integrated, but the color will start to fade, it will lose its original personality, freshness and structure. The wine will trade its primary fruit flavor for flavor notes of tobacco and cedar. The most useful factor is your taste buds i.e., what is good for some is not so good for others. The life span of all wine is finite and will eventually reach an over-the-hill flavor. White wine will not age long (think 2 or 3 years, at most 10) while red wines will last a little longer (think 5 to 6 years, at most 20). It is unfortunate when a wine is over-the-hill, because you cannot do anything to improve it; it is simply past its peak. To put it in simple terms, it is a dead wine.
This wine fault is caused in wine when it is exposed to excess oxygen. White wine will become brownish and ruddy and smell like sherry or cider. Red wine will look brownish-orange and will seem lifeless and flat. Air triggers a chemical reaction that converts alcohol to acetaldehyde and creates flavors of grass, nuts and apples. Oxidation is a common complaint and it can begin during winemaking, incorrect storage or hours after opening the bottle. Oxidation is one of the most common faults in older wine.
4. Heat Damage (cooked/maderized)
Heat exposure is detrimental to the quality of wine. Wine can be ruined by exposure to heat and will result in a wine that tastes like roasted stew or burnt fruit and will smell jammy or like cooked sugar. Ideally wines should be stored between 55 to 65F. Temperatures over 70F for a long time can permanently taint the wine and above 80F, you are starting to cook the wine. Cooked wine will become more tangy, astringent and rough. The wine fruit flavors will become secondary to acid. Light also contributes to the harm and the glass bottle amplifies the heat from the sun. The heat will cause the release of glucose-bound flavor precursors and decrease the protective sulfur dioxide, which causes the sensory character to change. The easiest thing to look for is a leak, disconfirmed cork or a pushed cork. So, heat damage can be disastrous for wine and will most likely ruin the bottle.
5. Brettanomyces (Brett)
Brettanomyces in wine contributes to earthy smells like: barnyard, horsey, sweaty socks or cured meat. Brett is a spoilage yeast that causes wine to disguise its real flavors and become funky by altering the palate and bouquet. Brett yeast grows slowly and feeds on a wide range of substrates and can survive anywhere. Although Brett can occur in white wine, it is a most common issue in red wines. Brett is not harmful to consume and can be both good or bad to wine aromas and flavors, so it is up to the taster to determine the “like”. Winemakers go the extra mile to keep their production facilities clean to prevent Brett in wine, so that it does not overwhelm the wine.
6. Volatile Acidity (VA)
Volatile Acid, also known as VA, refers to the acidic elements of wine that are gaseous rather than liquid, therefore they can be smelled. The aromas range from a sniff of acetone or nail polish, paint thinner, to downright vinegar. All wine has some degree of VA and VA is the process of wine turning into vinegar. VA is mostly caused by a bacteria (Acetobacter Aceti) in the wine creating acetic acid and with its byproduct ethyl acetate. With the help of oxygen, acetobacter converts sugar and alcohol into acetic acid. The best way to stop VA is to make sure everything has been thoroughly cleaned and disinfected. At low levels, VA adds complexity, at high levels it ruins the wine’s fruit flavor. VA is one of the fault parameters that has a legal limit; 1.2 g/l for white wine and 1.4 g/l for red wine. VA is basically unpleasant and at high levels, your wine has soured.
According to a chemical definition, reduction is a process that involves the loss of electrons, but in wine, it is the process of producing volatile sulphur compounds or mercaptans. Aromas range from struck match to garlic, gun flint, rubber and rotten eggs. Reduction is the opposite of oxidation. It happens when wine has limited exposure to air and that leads to volatile sulfur compounds. Minor wine reduction can be “blown off” through aeration. Another method that may help your wine is to drop a copper penny in the wine and swirl it around. These two methods may improve your wine.
A few other faults include secondary fermentation (think tiny bubbles in the wine), UV light damage wet wool sweater), tartrate crystals and herbal aromas (smells green).
Now that you know more about the types of wine faults, you can be more informed when you taste in the future, and have a better wine tasting experience. Enjoy!