Will beer in a keg go bad?

How Long Does Keg Beer Stay Fresh?

One of the joys of serving beer from a keg is the freshness and quality it can deliver—when handled correctly. But yes, beer in a keg can go bad, and how long it lasts depends largely on the method of dispensing and storage conditions.

When kept under proper conditions—using CO2 for dispensing and maintaining consistent refrigeration (around 38°F or 3°C)—freshness can last well. Non-pasteurized draft beer, which is more delicate and full of flavor, typically stays fresh for about **45 to 60 days**. Pasteurized beer, having undergone a heat-treatment process that extends shelf life, can last longer—generally **90 to 120 days**—under the same controlled environment.

However, there's a critical caveat: the way you tap the keg makes all the difference. Many people use what’s known as a "party pump," a hand-pump system that forces air into the keg instead of CO2. While convenient for short gatherings, this method introduces oxygen, which rapidly degrades the beer. In such cases, the clock starts ticking fast—**the beer remains drinkable for only 8 to 12 hours** before it begins to taste flat and stale.

Oxygen is one of beer’s worst enemies, causing oxidation that dulls flavors and introduces off-notes. That’s why maintaining a sealed, CO2-pressurized system is crucial for preserving quality over time.

Ultimately, if you're storing a keg for any length of time, skip the hand pump. Use proper draft equipment, keep it cold, and you’ll enjoy crisp, flavorful beer until the last drop. Whether it’s for a party or a taproom, respecting the science behind draft systems ensures every pour tastes just as the brewer intended.