While heat will shorten the life of a beer, it does not make it go bad, spoil it, or skunk it in the short term. Extended exposure to elevated temperatures will accelerate aging and oxidation, contribute to off-flavors, and reduce the beer’s drinkability.
All beer has a shelf-life. In most cases, the sooner it can be consumed at a proper temperature, the better for the drinker’s enjoyment.
Bottles, cans, and kegs of beer all contain at least a little oxygen. Given time, the chemical reaction of the beer and oxygen together will result in oxidation. Oxidation causes a stale, cardboard-like taste to the beer.
According to Craft Beer USA, “A general rule of thumb for the brewing industry is that beer stored at 100°F for one week tastes as old as beer stored at 70°F for two months, or as old as beer stored at 40°F for one year.
Refrigeration will dramatically slow the natural oxidation process of beer. Storing beer at room temperature away from natural light will also curb oxidation, just not as effectively.
That’s all to say that beer isn’t too delicate to handle the transition from a refrigerator to room temperature and back again, even a couple of times.
From the brewing process through storage of the final product, homebrewers need to be mindful of temperature control each step of the way.