What makes beer go bad?

1. Oxidation: This is the biggest culprit. It's a chemical reaction where oxygen interacts with the beer's ingredients, particularly hops, creating off-flavors.

* Signs: Stale, cardboard-like taste, loss of aroma, and a dull appearance.

* Prevention: Store beer in dark, cool environments to minimize oxygen exposure.

2. Light Exposure: Light, particularly UV rays, can accelerate oxidation and break down hop compounds, resulting in a skunky, unpleasant taste.

* Signs: Skunky aroma, loss of bitterness.

* Prevention: Store beer in dark bottles or cans, or use opaque beer glasses.

3. Temperature Fluctuations: Extreme temperature changes can affect the balance of flavors and aromas.

* Signs: Muddy taste, loss of carbonation.

* Prevention: Store beer consistently in a cool, dark place (ideally around 45-55°F). Avoid storing beer in direct sunlight or near heat sources.

4. Microbial Contamination: Microorganisms like bacteria and yeast can cause spoilage, resulting in sour, funky, or off-putting flavors. This is more common in homebrewing, but can happen with commercial beers under poor storage conditions.

* Signs: Sour, vinegary, or funky flavors, cloudiness.

* Prevention: Store beer in sealed containers and avoid exposing it to unsanitary environments.

5. Time: Even properly stored beer will eventually degrade. The aging process can cause the beer to lose its freshness and develop subtle changes in flavor.

* Signs: Dullness, slight loss of carbonation, subtle changes in aroma.

* Prevention: Consume beer within its recommended shelf life, which varies depending on the style and brewing process.

Key points to remember:

* Bottled vs. Canned: While both methods are acceptable, cans offer slightly better protection against light and oxygen.

* Nitrogen vs. CO2: Nitrogen-charged beers, like Guinness, tend to have a finer head and a smoother mouthfeel. They also often have less hop aroma, making them less susceptible to oxidation.

* Freshness: Look for "bottled on" or "packaged on" dates to gauge the beer's freshness.

Enjoy your beer! Knowing these factors will help you store and enjoy it at its best.