Drinking opened wine that has been sitting for an extended period raises a common safety concern, but the risk of serious illness is low. Once uncorked, wine begins a natural process of degradation when it is exposed to the air. This change often leads to unpleasant flavors and aromas, but it rarely results in a beverage that is dangerous to consume. The primary issue with old, opened wine is its palatability, which decreases significantly over time as its chemical composition shifts.
Pathogens and Food Safety Risk
The structure of wine makes it a poor environment for the bacteria responsible for serious food poisoning. Most human pathogens, such as E. coli or Salmonella, cannot survive due to the wine’s high acidity (low pH, often 3.0 to 4.0). The ethanol present in the wine acts as a natural antimicrobial agent, further inhibiting bacterial growth.
Therefore, severe, life-threatening food poisoning from drinking spoiled wine is an extremely rare occurrence. While spoilage can happen due to microbial activity, the bacteria involved are usually non-pathogenic wine spoilers, like Acetobacter, not the kind that cause major illness. If the wine was improperly handled or stored during production, contamination is possible, but for a standard opened bottle, the risk of acute foodborne illness remains minimal.
Chemical Transformation and Spoilage
The primary spoilage mechanism in opened wine is chemical transformation driven by exposure to oxygen. This process, known as oxidation, begins the moment the cork is pulled and the liquid comes into contact with the air. Oxygen reacts with the ethanol in the wine, initially producing a compound called acetaldehyde.
Acetaldehyde imparts undesirable, flat, and nutty or sherry-like flavors, stripping the wine of its fresh character. When oxygen is present, airborne bacteria from the genus Acetobacter can convert the alcohol into acetic acid. Acetic acid is the main component of vinegar, and its presence causes the wine to taste sharp and sour, making it unpalatable. These changes solely affect the taste and aroma profile, turning the wine into something unappealing rather than toxic.
Health Effects of Consuming Spoiled Wine
Consuming wine that has undergone extensive chemical spoilage can still lead to temporary, non-fatal health consequences. The most common effect is mild gastrointestinal upset, which may include nausea or a stomach ache. This discomfort is primarily due to the increased concentration of acetic acid, which can irritate the sensitive lining of the stomach.
Some individuals may experience a headache after drinking spoiled wine, which is often mistakenly attributed to the spoilage itself. This reaction is more likely linked to the presence of biogenic amines, such as histamines, or sulfites, whose concentrations can shift during spoilage. The elevated levels of acetaldehyde, a compound known to be more toxic than ethanol, may also contribute to a general feeling of malaise, similar to a mild hangover. Although the experience is highly unpleasant, these effects are typically mild and resolve quickly.