The term “expired” for wine does not imply a strict expiration date like spoiled milk or meat. Wine is an agricultural product whose consumable life is limited. “Expired” refers to wine that has undergone chemical changes, usually due to improper storage or excessive time, causing it to deteriorate past its peak drinkability. This decline is a natural process accelerated by exposure to oxygen and heat, unlike most foods which spoil due to external contamination.
Health Implications of Consuming Deteriorated Wine
The most frequent question about spoiled wine is whether it poses a health risk. Consuming wine that has merely deteriorated in flavor is generally not dangerous. The high acidity and alcohol content create an environment hostile to most foodborne pathogens responsible for severe illness.
The main consequence of drinking spoiled wine is typically an extremely unpleasant sensory experience. If you consume a large amount of wine that has turned into vinegar, the resulting high concentration of acetic acid can cause mild gastrointestinal upset. This may manifest as a stomach ache, nausea, or, in rare cases, diarrhea, especially in individuals with a sensitive digestive system.
This mild discomfort is a reaction to the wine’s acidity and bacterial spoilage byproducts, not severe food poisoning. The alcohol acts as a natural preservative, inhibiting the growth of harmful bacteria like E. coli or Salmonella. True toxicity from spoiled wine is extremely rare and is generally limited to the ingestion of non-pathogenic spoilage organisms.
If wine has chemically deteriorated, it is primarily a matter of quality and taste rather than safety. The primary risk is an unpalatable drink and a spoiled evening. It is wise to trust your senses; if a wine tastes foul, it should be discarded.
Recognizing Sensory Cues of Spoilage
Spoilage can often be detected visually before tasting. Oxidized white wines deepen in color, shifting from pale straw or gold to a dark amber or brownish hue. Red wines lose their vibrant purple or ruby color, becoming duller and taking on a brick-orange or brown edge.
Other visual cues include a noticeable haziness or fine bubbles in a still wine, indicating unintended secondary fermentation. The cork itself may also be a warning sign; if it appears pushed out or sticky, the wine may have been exposed to excessive heat, compromising the seal.
The aroma is the most reliable detector of wine faults. A high concentration of volatile acidity, caused by the formation of acetic acid, will produce a sharp, vinegary smell. If the wine smells like nail polish remover or paint thinner, this is a distinct sign of ethyl acetate, a related compound created by the same acetic acid bacteria.
Another common fault, known as “cork taint,” is caused by the chemical compound 2,4,6-trichloroanisole (TCA). This fault imparts a pronounced, musty aroma often described as damp basement, wet cardboard, or moldy newspaper. Upon tasting, spoiled wine lacks its characteristic fruit flavors, often presenting as flat, overly sharp, or intensely sour.
The Underlying Chemistry of Wine Deterioration
Wine deterioration is primarily driven by two mechanisms: oxidation and microbial spoilage. Oxidation begins when oxygen interacts with the ethanol and phenolic compounds. This reaction is accelerated by a poor seal or an open bottle, initiating chemical transformations.
Ethanol is first converted into acetaldehyde upon contact with oxygen. Acetaldehyde is responsible for the flat, bruised apple, or nutty aromas typical of oxidized wine. Over time, this process continues to the final stage of deterioration with the help of specific bacteria.
The presence of Acetobacter bacteria, which are common in the environment, accelerates the conversion of acetaldehyde into acetic acid. Acetic acid gives vinegar its characteristic sharp flavor, a process known as acetification. Since the bacteria require oxygen for this conversion, exposure to air is the dominant factor in wine spoilage.
Other spoilage organisms, such as the yeast Brettanomyces, can also compromise wine quality. They produce compounds like 4-ethylphenol and 4-ethylguaiacol, which create distinctive off-odors described as barnyard, medicinal, or smoky. Wine deterioration is ultimately a microbial or chemical shift away from the desired balance of flavors and aromas, rendering the product unpalatable.