How long will a 5 gallon beer keg last?

How Long Does a 5-Gallon Keg Really Last?

Planning a party or stocking your home bar? A 5-gallon keg is a popular choice for keeping fresh beer on tap. But how long can you actually enjoy it before it goes flat or stale?

The lifespan of your keg largely depends on whether the beer inside is pasteurized or not. Pasteurized beers, which include many imported and mass-market domestic drafts, are heat-treated to extend shelf life. These kegs typically last anywhere from 90 to 120 days—about 3 to 4 months—when stored at the proper temperature (ideally around 38°F).

On the other hand, unpasteurized draft beer, often favored by craft breweries for its fresher taste, doesn’t go through this heat process. That means it’s more perishable. You can expect an unpasteurized keg to stay fresh for roughly 45 to 60 days, or 6 to 8 weeks, under the same cool, stable conditions.

Temperature control is key. If the keg gets too warm—or worse, cycles between cold and warm—oxidation and bacterial growth can speed up, degrading both flavor and quality. Once the keg is tapped, keeping it connected to a properly functioning CO₂ system helps maintain carbonation and freshness.

It’s also worth noting that while the beer might still be safe to drink after these timeframes, the taste will likely degrade. Flat, stale, or off-flavors are telltale signs it’s past its prime—even if nothing is technically “wrong” with it.

So if you’re buying a keg, consider your timeline. For longer storage, pasteurized is the way to go. But if you're after peak flavor and plan to enjoy it quickly, fresh unpasteurized beer from a local brewery can be well worth the shorter shelf life.