The length of time beer stays fresh in a keg depends on many important factors, such as whether the keg is sealed or tapped, how the beer is dispensed, the style of beer, and how it is stored. Usually, an unopened, properly refrigerated keg of beer can remain fresh for two to six months. The variation in shelf life is due in part to the brewing process. Pasteurized beers, which undergo a heat treatment to kill bacteria, can normally last on the longer end of that range—up to six months. In contrast, unpasteurized beers, often found in craft breweries, are more delicate and should be consumed within six to eight weeks even when kept cold.

Once a keg is tapped, the clock mostly starts ticking much faster. If you're using a CO₂ dispensing system, like those found in bars or home kegerators, the beer can maintain its freshness for about 4 to 8 weeks. CO₂ helps preserve the beer by keeping oxygen out and maintaining carbonation. However, if you use a manual pump—commonly seen at parties and pubs —that introduces oxygen into the keg, the beer will typically go stale within eight to twelve hours. Oxygen speeds up oxidation and encourages bacterial growth, quickly degrading the beer’s flavor and quality.

Home draft systems like PerfectDraft are designed to prolong this freshness. Their 6-liter kegs, when kept chilled in the machine, can keep beer fresh for up to thirty days after tapping thanks to their pressurized and sealed environment.

To ensure your keg beer lasts as long as possible, it's fundamental to store it at a consistent, cold temperature (ideally 3–5°C) and to use a clean, well-maintained dispensing system. When stored and handled properly, keg beer can offer excellent freshness for a long time.

Read other articles : How much does a keg of beer weigh ? and How many pints in a keg of beer ?