The standard for storing packaged beer is “the colder the better,” according to the National Beer Wholesalers Association (NBWA) based in Alexandria, Va. The trade group recommends that temperatures between 33 degrees and 49 degrees are optimal for preserving the quality and integrity of the product in convenience store beer caves.

It is also imperative that retailers know that the beer has been held at this temperature range during transport to their stores, NBWA emphasized.

Cold temperatures make it possible to retain the level of carbonation that is developed in the beer during the brewing process. Because carbon dioxide (CO2) expands as it heats up, storage at higher temperatures depletes it over time resulting in a flat beverage.

While brewers try to limit the amount of oxygen that remains in the bottle or can during the packaging process, enough remains to affect the quality of the beer during storage. Therefore, lighter beers that are stored in warm temperatures and are allowed to oxidize for periods of time may develop off-flavors of wax, honey, paper or wet cardboard that overwhelm the flavors of the original product. Darker beers such as ales may take on a sherry taste. Unpasteurized craft beers are especially susceptible to temperature-related flavor changes.

To demonstrate the relationship between high temperatures and beer degradation, industry giant Miller Brewing Co. offered an example of what happens when the product is held at refrigerated temperature (38 degrees), room temperature (68-72 degrees) and in the trunk of a car on a hot day (90-98 degrees). Commonly known as the 3-30-300 rule, it concludes that the drinkability of beer kept at the highest temperature for three days was the same as the product held at room temperature for 30 days or under refrigeration for 300 days.