As a beer enthusiast and brewer, I can confidently say that drinking a hot beer is not ideal, but it is certainly possible. The flavor and overall drinking experience may not be as pleasant as when the beer is served at its optimal temperature, but it won't cause any harm to your health.
When beer is served hot, certain undesirable characteristics can emerge. For example, the aroma may become muted or even unpleasant, and the taste can be overly sweet or malty. Carbonation levels may also be affected, resulting in a flat or overly fizzy beer. These changes occur because heat can accelerate the aging process and cause the beer to oxidize more rapidly.
However, if you accidentally find yourself with a hot beer and don't have the means to cool it down, there's no need to fret. Simply placing the beer in a refrigerator or an ice bucket for a while will help it cool down gradually. Rapid temperature changes, such as putting it in the freezer, should be avoided as they can cause the beer to foam over when opened.
It's worth noting that beer can tolerate temperature fluctuations to some extent. Brewers often subject their beers to temperature variations during the fermentation and conditioning processes without causing any harm to the final product. So, if your beer has warmed up and then cooled down again, it is still perfectly safe to drink.
That being said, it's best to avoid subjecting beer to extended periods of warmth. Prolonged exposure to heat, especially in direct sunlight, can lead to off-flavors and spoilage. This is why it's important to store beer in a cool place, away from sunlight and extreme temperatures.
In my personal experience, I once left a six-pack of beer in the trunk of my car on a scorching summer day. When I finally retrieved it, the beer was definitely warm, bordering on hot. I decided to give it a try anyway, and while the flavors were not as vibrant as they would have been if the beer had been properly stored, it was still drinkable. The carbonation was a bit lacking, but it didn't ruin the overall experience.
To sum it up, drinking a hot beer is not ideal, but it won't harm you. If you find yourself with a warm beer, simply cool it down gradually, and you should still be able to enjoy it. Just remember to store your beer properly in the future to ensure the best possible flavor and drinking experience.