1. Not all beers age the same, so know what you’re drinking
Unfortunately, there’s no real timeline for when a certain beer will age into the “not fresh” category. But there are a few good rules of thumb you can use to know whether you should be worried about a beer's freshness or if you can stash it and still have a delicious beer one year down the road.
First, check the ABV: if it’s higher than 8%, you generally don’t need to worry about rushing to drink it (more on cellaring beer later!).
Next, check the style. If it’s a sour or a smoked beer, then it falls into the same category as high-alcohol beers. However, if it’s an IPA or another hop-centric beer, like amber lagers, American pale ales, or American strong ales, you’re holding a beer that’ll age quickly (IMPORTANT: this even includes some of those 8+ percenters that fall into these styles!). Herz says these should be consumed fresh because of their hop aromatics, which add to the distinctive flavor of the beer and fade over time.
Lastly, look for pasteurization. Herz points out that most craft breweries in America don't pasteurize their beers, so their shelf-life is shorter than mass-produced lagers, which are pasteurized.
2. If it’s not going into storage, drink the beer within three months of the bottling date
At least if you’re holding an unpasteurized beer. Can't tell when the beer you're holding was brewed? Check out FreshBeerOnly.com, which will educate you on how to find a bottling or packaging date on a ton of breweries' cans and bottles.
For pasteurized beer, well, you've got more time than a few months. In a course that Herz and Chef Adam Dulye taught about food and beer, they cited research from MillerCoors that stated that "storing beer in the following conditions will result in equivalent flavor loss: 1) 3 days in the trunk of a hot car (90 F), 2) 30 days at room temperature (71 F), and 3) 300 days in the refrigerator (33 F)." Which means you have almost an entire year to drink that can of pasteurized beer before it goes bad! Also, if you can't find time to drink a can of beer in 300 days, maybe beer isn't your thing.