Beer can at least last 1–7 days in a growler. If sealed properly and kept in a cool place, it may stay good for 2 weeks. However, several factors can impact its shelf life.
(1) Storage:
- Cold Storage: Beer should be kept at a cool, consistent temperature (ideally in a refrigerator at 38°F / 3°C). This helps to slow down oxidation and preserve carbonation.
- Room Temperature or Warm Storage: Storing beer at room temperature can accelerate spoilage, making the beer flat more quickly.
(2) Type of beer:
- Light beers (like pilsners, lagers, pale ales): These degrade faster due to their lighter body and hop profile. Carbonation loss and oxidation will be more noticeable within 2–3 days.
- Heavy or Dark Beers (like stouts, porters, or barleywines): These beers tend to last longer in a growler due to their higher alcohol content and more robust flavor, which helps them withstand oxidation longer.
- Sours and High ABV Beers: Sour beers or high-alcohol brews age better than others.
(3) Pressurized or Non-Pressurized Growlers
- Pressurized Growlers: These growlers have a CO2 system (often a regulator and tap system) to maintain pressure and carbonation. This helps preserve the beer’s freshness for a longer period.
- Non-Pressurized Growlers: These growlers rely solely on sealing and refrigeration to preserve beer. Without added pressure, the beer’s carbonation will be lost more quickly, particularly after opening.
(4)Opened or Unopened
- Unopened Growlers: When sealed and stored properly, unopened growlers can retain their carbonation and flavor for a longer time, typically one to two weeks, depending on the beer type and conditions.
- Opened Growlers: Once opened, beer begins to lose carbonation quickly. And the exposure to air accelerates oxidation. The beer will still be drinkable, but within a few hours to a day, it will become flat and stale.