Is an Opened Can of Beer Still Drinkable After 2 Days?

When it comes to leftover beer, many people wonder if an opened can or bottle can still be consumed after a couple of days. The options range from a quick drink to a deliberate choice in extreme circumstances. However, the health risks associated with drinking stale beer are significant, and it's generally not recommended. This article will explore the potential risks and why consuming old beer is not a good idea.

Is It Safe to Drink Beer After It Is Opened?

The short answer is no. Once a can or bottle of beer is opened, the beverage is exposed to air, leading to a variety of chemical and microbial changes that can render it unsafe for consumption.

According to health and safety regulations, by law, any opened beer, regardless of the brand, should not be drunk after a certain period. In the case of a big can of Foster's, the contents are likely to lose carbonation within a day, and an opened bottle of IPA refrigerated will last about 24 hours. However, after 24 hours, it is recommended to treat the beer as past its prime.

Health Risks and Chemical Changes

From a chemical standpoint, the alcohol in beer can be oxidized to produce carboxylic acids. Ethanol, the active component in beer, can be oxidized to ethanoic acid using an oxidizing agent. The balanced equation demonstrating this process is:

CH3CH2OH 2[O] → CH3COOH H2O

Here, the right-hand side of the ethanol molecule is unchanged, and the reaction involves the -OH group. Oxidation can lead to a sour, vinegar-like taste and a potential risk of gastrointestinal issues such as a burning sensation in the chest and neck, a sour sensation in the mouth, and bloating.

Microbial Contamination and Bacterial Growth

Beyond chemical changes, the growth of bacteria is another significant concern. Once a beer is opened, it is exposed to the air, which can facilitate the proliferation of harmful bacteria. Within a couple of hours, bacteria begin to grow, and by the first day, the beer is likely to be unappetizing due to the growth of excess bacteria. After two days, the beer may harbor a significant risk of foodborne illness.

While it's possible that some adventurous individuals may consume beer that is several days old, the health risks are substantial. Bacterial contamination can lead to various gastrointestinal issues, such as nausea, vomiting, and diarrhea. These symptoms can range from mild to severe, depending on the type and quantity of bacteria present.

Why Some Beverages Are Safer

It’s important to note that not all beverages pose the same risks when left open for extended periods. Wine, liquor, and apple cider vinegar, for example, have higher alcohol or acid contents that can inhibit bacterial growth. However, even these beverages are not guaranteed to be safe if left open for too long. Beer, water, and carbonated drinks like soda remain at risk for microbial contamination.

In summary, while the thought of drinking an old can of beer might be tempting, the potential health risks far outweigh any perceived benefits. It’s best to err on the side of caution and consume beer within its freshness period to avoid the risks associated with stagnant and potentially harmful beverages.