How Long Does A Keg Last? You'll Be Surprised At The Answer
You can’t have a party without a fresh keg of beer.
I was very worried when I realized my own keg had been tapped a month ago. Even though it was mostly full, I didn’t want to serve stale beer to my guests. I wondered if I should drink it or just open a new one. But I couldn't allow such a waste of delicious beer, so I decided to investigate a bit more until I finally found the answer.
How long does a keg last? Generally speaking, a keg can last for months if stored in the proper conditions, though a variety of factors will influence the shelf-life of your keg, including pump type, storage temperature, and beer type.
Thankfully, my keg was alright—and the party was a success!
In this guide, I’ll go over the science behind keg storage and examine the different factors that influence the shelf-life of your keg.
Keep reading to find out more!
Why Storage Temperature Matters
Let’s start by examining an important issue: storage temperature.
Though it may not seem so important at first (after all, you can always chill it again later, right?), storage temperature is one of the primary factors influencing the freshness of your beer.
You don’t want to store your beer in temperatures that are too hot or too cold, as each can have adverse effects on the quality of your beer.
Specifically, you can expect the following:
If your beer is too hot
Storing your beer in temperatures greater than or equal to 50 degrees Fahrenheit can speed up the oxidation process whereby your beer’s chemical makeup is gradually altered, resulting in staleness.
But it’s not just that. Bacteria can even begin to form in your keg if you store it under these conditions, greatly affecting the taste and overall quality of your beer.
If your beer is too cold
So we know storing your beer at temperatures that are too hot is a big no-no.
But what happens when your beer is kept in conditions that are too cold? While you want to store your keg in a cold, dark place, leaving it somewhere 28 degrees Fahrenheit or below could cause it to freeze.
Frozen kegs can even burst open due to carbon expansion on the inside.
According to science, the proper storage temperature for your keg is 38 degrees Fahrenheit - or 3,3°C-.
Make sure to approximate this temperature when storing your keg if you want beer that stays fresh for months to come.
How Do You Know When a Keg Goes Bad?
With all this being said, how do you know when a keg of beer goes bad? Let’s take a look at a few common signs that your beer has lived past its prime:
The most obvious red flag of a bad keg is a foul taste.
Your beer may be unnaturally sweet, with the taste of ripe apples or other fruit. Conversely, it may also taste like sulfur. Either way, these strange (and potentially foul) tastes can let you know right away that your keg isn’t good anymore.
You may not have to taste your beer to know it’s bad.
Beer from a stale keg often has a cloudy appearance. If your beer is unusually cloudy or foamy, this is a sign that it’s no longer good.
NOTE: a little foam is okay — particularly if you’re using a manual pump —.
However, you should have second thoughts about beer that appears way too “bubbly.”
A keg that’s stayed past its welcome can also smell bad.
Much like a bad taste, this smell can be sulfuric or overly sweet. In simple terms, it won’t smell like the beer you know and love. While drinking old beer won’t necessarily harm you, it won’t taste great, either, and won’t win you any favors at your next party.
Can a Keg Be Tapped Twice?
If you’re like most of us, you can’t drink a keg of beer in one sitting—even if you’re surrounded by some of your rowdiest friends. Naturally, you’ll want to know if you can tap your keg twice. The good news is yes, you can tap a keg twice —with some limitations, of course.
In the event that you’re using a manual or O2 pump, you’ll unfortunately only get one tap out of your keg.
If you’re using a CO2 pump, however, you should be able to tap your keg at will, as you aren’t introducing any foreign gases into the keg, which already comes with CO2.
With that being said, it won’t matter if you don’t store your keg the right way, so make sure to follow all steps of the storing and tapping process if you want to get maximum use out of your beer.
Kegs Shelf-Life: Manual Pumps vs CO2
With all this being said, let’s turn our attention to another important issue when it comes to your keg: pump style.
Generally speaking, there are two major styles of keg pumps: manual pumps and those that operate with CO2. You may not have thought much about it, but the style of pump you use could influence the shelf-life of your keg (and the quality of your beer).
What’s the difference? Let’s take a look:
If you’ve ever taken a keg to a party, it’s likely you used a manual pump. Manual pump kegs work by pumping oxygen into your keg, forcing the beer out and into your glass. This is a highly effective method at dispensing alcohol, but it doesn’t do much to keep your beer fresh.
Here’s why: once oxygen is introduced into your beer, the oxidation process hits rapid speed. Manual pump kegs can go stale in a few as eight hours as a result.
As such, you don’t want to use one of these pumps if you’re looking to store your keg over the long term.
A CO2 pump works similarly by applying pressure to force the beer out of the keg.
Unlike manual pumps, however, CO2 pumps don’t use oxygen. Instead, they work by using carbon dioxide, which helps your beer stay fresh longer.
With a CO2 pump, your keg can last for months, even after it’s been tapped!
Of course, there are other considerations you’ll want to keep in mind, so make sure to keep reading to ensure your beer stays as fresh as possible.
3 Practical Tips to Keep Your Keg Fresh
We’ve touched on this a little bit already, but it’s worth tackling them again. If you want your beer to last a long time, you’ll need to keep your keg fresh.
Let’s go over some of the most effective ways to do that:
#1 Buy it Fresh
The first step to a long-lasting keg is to buy one that’s freshly made. If you buy a keg that’s already nearing it’s “sell-by” date, you’ll have far less time with it for yourself.
REMEMBER: the sell-by date isn’t the same as an expiration date, which could be months after you tap the beer if you follow the right storage instructions.
#2 Store it Correctly
This leads me to my next point: you’ll need to store your keg properly in order for it to last a long time.
Ideally, this is somewhere cool and dark, as both heat and light are damaging to the quality of the alcohol inside the keg. This also means keeping the right pressure on your kegerator. Pressure that’s too low can result in excessively foamy and flat beer, and pressure that’s too high can lead to waste, as the beer will shoot out of the keg too rapidly and be foamy, as well.
The amount of pressure you need to use on your kegerator differs by the type of beer you use, but for most standard ales and lagers, you should keep the machine anywhere from 10-12 PSI.
#3 Use The Right Pump
Finally, you’ll want to use the right pump. As discussed, CO2 pumps are the way to go if you’re looking to maximize the shelf-life of your keg.
Differences in Shelf-Life Depending on the Type of Beer
In some ways, the shelf-life of your beer has nothing to do with the keg itself. You’ll also want to pay attention to the contents of your keg.
Remember that different beers have different shelf-lives.
A good rule of thumb is this: the stronger the alcohol content, the longer the beer will last.
Still, even normal ales and lagers can last up to four months—not too shabby, if you ask me.
Broadly speaking, the shelf-life of your draft beer will depend on whether it’s:
Pasteurized beer, or beer that’s been treated for damaging microorganisms, has the longest shelf-life of any draft beer, lasting anywhere between 90-120 days (3-4 months) in total.
Assuming proper storage conditions, unpasteurized beer, or beer that hasn’t been treated pre-packaging, will last between 45-60 days (or 6-8 weeks) total.
Remember: this timeline will start before you tap it.
By now, you should have a good idea whether that keg in your basement is good or bad. Following the right protocols, you can extend the shelf-life of your kegs for months—saving you money and ensuring you always stay the life of the party.
If you’re looking to buy a keg in the near future, make sure to use this guide as your ultimate reference for both storing and tapping!