Beer goes flat when it is opened and then put in the fridge for more than a few hours. Our best advice, if you're going to have a beer just finish it. Flat beer much like flat soda has lost its carbonation and gets a stale taste. Beers with low ABVs stored on a shelf unopened will go flat within about 6 months.
Keeping this in view, is it safe to drink flat beer?
Beer doesn't become unsafe to drink as it matures, but it will begin to taste flat -- either because it loses flavor or develops an off-putting flavor profile. The alcohol content of beer (and wine, for that matter) is determined during the fermentation process and will not change over time.
How do you make beer go flat?
How to Make Beer Flat
- Take the beer out of the refrigerator and let it warm to approximately room temperature.
- Pour the beer in a large bowl. The size of the bowl depends on the amount of beer you're using.
- Whisk the beer for five to 10 minutes to remove the carbonation. Let the beer sit for five minutes before using.
What do they mean by stale beer?
The aftermath of a party is like a gross beer scavenger hunt. After finding all of the containers your friends left sitting around the night before, you usually pour out all the old, stale beers. But before you drain that last bottle of ale, consider putting your flat beer to better use.