Signs That a Wine has Gone Bad
Most wines will improve with age but too much age will ultimately spell the end of what was once a great wine. 200 year old shipwreck wines are lucky if they taste like wine at all. While they may sell at auction for high prices, the most likely scenario is that the wine tastes like saltwater, nail polish remover, vinegar, or some combination of the three after extremely extended aging. Every wine ages differently and will reach optimal enjoyability at a different time. To complicate matters more, each drinker has different interpretations on what is the perfect wine. Dry, skin fermented red wines will often peak at three to six years of age for your average drinker. Fruit driven whites and rosés might peak as early as six or eight months. A red wine that is packed with tannin and acid may take two decades to really wake up. After a wine passes prime, it will begin to show subtle age related signs that are unfavorable to most. In this article, I will spell out some of those signs.
When Does the Wine Aging Clock Start?
The year on the wine bottle is not the time that it is bottled but rather the time that the grapes were harvested. Wines from the northern hemisphere will generally be harvested between September to November, so a 2017 Cabernet Sauvignon from Walla Walla, Washington will have likely been harvested around October of 2017 which is also when the fermentation would begin. The southern hemisphere is harvested towards March, April or May so a 2017 Chilean wine would be about six months older than a 2017 California wine. White wines are usually harvested first, followed by early ripening red wines and finally red wines that require a longer season to ripen fully.
What Drives the Ageability of a Wine?
There are a few factors to be considered here. A wine intended to be aged should drink like a caricature of a great wine when young. This means acid, tannin, pleasing aromas, and key flavors are really whacking you in the face... so much so that the wine will not taste particularly good or in balance for a long while. Over time, some tannin will precipitate while others will bind together contributing to a more pleasing texture. Some of the more overpowering smells which often include earthy or tobacco like components in a young red wine will blend into the background and be perceived as savory or spice like. As the more intense components settle down, the dark fruit or red fruit can shine through and come into balance.
A wine with big aging potential, should be virtually "flawless". Subtle oxidative flaws can really take over as a wine gets older and reacts with more oxygen. These would generally include smells like vinegar, sherry, or nail polish remover. Subtle reductive flaws (resulting from an oxygen starved wine) are a little more capable of hiding or blending in over time, especially for red wines. These would include musty or sulfury smells.
The pH, tannin, and free sulfur dioxide levels are major contributors to a wines long term stability. Low pH (high acid) levels in the 3.0-3.2 for a white wine and 3.35-3.55 for a red wine will usually have better aging potential as they tend to be more microbially stable and oxidation resistant. Tannin readily binds with oxygen, and can act as an anti-oxidant, stealing oxygen molecules before they can cause damage. Sulfur dioxide (Sulfite or SO2) is a natural biproduct of fermentation but readily binds or oxidizes away requiring a small boost to maintain protective levels through the wine aging process. Wines made without the addition of sulfur dioxide are extremely rare and may contain higher headache forming hystamine and tyramine levels due to the likelyhood of more undesirable bacteria playing a role in the fermentation. In normal to high pH ranges these wines are very prone to microbial spoilage but some wine drinkers may view traditional spoilage indicators as "interesting" or "funky" (cough cough... "Natural Wine").
The bulk aging vessel is often an oak barrel, carboy, or stainless tank and eventually a bottle. During the pre-bottle stage, larger volumes can age more slowly and gracefully whereas small volumes have more difficulty with oxygen management due to the high headspace to wine ratio. Air permeable oak barrels slowly concentrate the wine as it evaporates and can provide some beneficial micro-oxidation to smooth things out. At most, a wine is usually aged for about two years in oak (even neutral oak), as it is plenty long enough and tends to be a chore to keep up with sulfur dioxide additions and prevent oxidation.
Once a wine goes into a bottle, there are a few things to consider. Clear bottles can accelerate aging by allowing light to the wine. Inexpensive corks can be more permeable than high grade natural, premium colmated, or premium agglomerated corks. More permeable means more oxygen and evaporation over time which can help age initially but limit the length of ageability. Screw caps are often fitted with oxygen permeable seals to more closely mimic the oxygen transmission rate of a high grade cork (too air-tight can lead to reduction related flaws). In general high quality cork products and screw caps will allow a wine to age very long. In extremely old wines, the corks are periodically replaced (every 40-50 years maybe) and the bottles are topped up to replace any evaporated wine. A wax sealed bottle helps but a cork will still eventually need replaced after many many years due to degradation.
Finally, storage conditions will impact the ageability of a wine substantially. A wine cellar should be cool with a relatively constant temperature and relatively dark. At an ideal temperature of 55°F a wine can age slowly and controllably. At 45°F aging will be greatly slowed by at least a factor of two, whereas a wine at 70°F storage will age substantially faster. If you don't have a cool place to store your wine, consider a good wine fridge. Large temperature fluctuations can cause more ullage (wine level slowly dropping) and risk of oxidation as the wine expands and pressurizes and contracts to create a small vacuum. Storing a wine on the side to keep the cork wet is ideal for longer storage periods.
How do you know if a wine has peaked?
This is a tricky one to determine. A wine is a constantly evolving thing, and everyone's taste preferences are unique to them. For me, a red wine is right in the sweet spot when the perception of acid and tannin are right where I want them and the wine is aromatically complex and has not rolled over towards the "old wine" or nutty smells (which some people love). When a red wine in a bottle is too young, one or two individual smells can dominate which can really diminish the experience. When a red wine is a little too old, it can become a little more approachable to some, but "flabby" or dull to others (lacking liveliness and particularly lacking acid/tannin balance).
Sometimes a red wine can gather new life as it gets way past its prime and enters the "old wine" territory. While this is not my preferred style, an older red wine can take on a whole new style, shedding fruit for nutty, almost sweet sherry characteristics much like a port wine.
The more tannic, and acidic red wines are often just right for me around 3-7 years. A more fruit forward red wine is usually tasty in the 2-4 year range. Anything that really begins to taste great at ten years and beyond to me is usually very painful on the wallet. That being said, if you prefer the "old wine" silky smooth tastes and nutty aromas, the wines that I enjoy at seven years may have another ten years in them for you.
When a red wine has really gone bad it will often take on the traditional "bad wine" indicators like acetaldehyde (nutty), ethyl acetate (nail polish remover), or acetic acid (vinegar).
White wine comes in many different styles from crisp, and acidic dry wines to sweet, juicy, fruit blasters and everything in between. White wines are generally very low in tannin since they are not fermented with the skins and seeds and rarely oak aged. A crisp, dry wine often benefits from a low pH (high acid) which is beneficial for aging.
Most white wines are best drank relatively young, like six months to two years. At the younger stage the wines will generally be more fruit driven and lively. As a white wine ages it can become more approachable. Wines like chardonnay are occasionally barrel aged and more stable due to the completion of malolactic fermentation. A white wine that is a little too old will start to lose pleasing fruit aromas as it exchanges them for more oxidized aromas. This also applies to fruit (non-grape) wines and rosés.
A white wine that has gone bad will generally show a visible color shift towards brown and begin to take on nutty smells. Sometimes an unfiltered white wine may undergo unwanted malolactic fermentation in the bottle, leaving it spritzy and buttery.
These are best drank very young and will rarely if ever benefit from ageing beyond about a year. The one exception would be a sweet fortified wine like a port which is intentionally oxidized to some extent. A old sweet wine can undergo a second fermentation in the bottle if any contamination with yeast occurs or if the wine was not properly stabilized. A sweet wine that is too old can taste cloying like sugar water as the fruit and perception of acid starts to diminish and the sugar really shines through.
Wines made from juice concentrate are rarely intended to be aged and suffer from chronically low tannin levels. Many new home winemakers will age a kit wine for many years. The wine will become "smoother" but in most kits that is not necessary as the wine is already lacking in intensity. The ideal age for most kit wines is generally about six months to a year of aging. A kit wine will brown over time and eventually can show traditional signs of over-aging like nail polish remover smell, sherry/nutty smell or occasionally other volatile acids like vinegar.
Does Price Matter?
If a store-bought wine is selling for a budget price it is probably intended to be drank relatively soon after purchase. More expensive wines often have more skin and seed time during fermentation and can age substantially longer. In some cases those expensive wines may taste worse than a budget wine at the time of purchase but can reward you if you can cellar it. If someone has a budget for a $100 bottle of wine, it is expected that they probably have a wine cellar and can throw it on the shelf for a couple years to stare at while checking their investment accounts.
Price is not always an indication of quality though but often does mean that the raw materials were a little more premium and the wine has had considerably more labor and less automation in the winemaking process. Sometimes small regional wineries will charge big dollars for really bad wine.