A 15 gallon keg is a common size for kegs of beer. Breweries and bars often use these to store and serve beer. But how many beers can actually be poured from a 15 gallon keg? The answer depends on a few factors.
What is a keg?
A keg is a small barrel used to store and transport beer. Modern kegs are made of stainless steel and have a smooth inner surface that does not react with beer ingredients. The most common keg sizes in the United States are the sixth barrel (5.16 gallons), quarter barrel (7.75 gallons), half barrel (15.5 gallons), and sixtel (6.6 gallons).
15 gallon keg
A 15 gallon keg, sometimes referred to as a half barrel, is a very common size. These kegs measure about 23 inches tall and 17.5 inches in diameter. The most popular brands of beer like Budweiser, Coors, Miller, and Heineken are packaged and distributed in 15 gallon kegs. This makes the half barrel a convenient size for bars, restaurants, and large parties to serve beer.
Factors that determine beer yield
There are a few key factors that determine how many 12 ounce beers can be poured from a 15 gallon keg:
1. Amount of beer in the keg
A full 15 gallon keg does not actually contain 15 gallons of beer. There is empty space at the top to allow for carbonation. The amount of beer is typically around 13-14 gallons. The exact amount depends on the brewery.
2. Alcohol percentage
Beers with higher alcohol percentages tend to be heavier, which reduces the overall yield. For example, a full-bodied 9% triple IPA would produce fewer beers than a 4% light lager from the same keg size.
3. Foam
When pouring a draft beer, foam is produced. The foam displaces some of the liquid beer, reducing the total amount. Heavily carbonated beers like wheat beers tend to produce more foam.
4. Spillage
There will inevitably be some wasted beer at the end of the keg from spillage. The dregs may be difficult to pour evenly. While waste can be minimized with good serving technique, some will be lost.
Standard beer yields
The typical yield from a 15 gallon keg is about 165 12 ounce beers. Here are some standard estimates for full kegs based on style:
- Light lager: 170 beers
- IPA: 160 beers
- Wheat beer: 155 beers
- Stout: 150 beers
These numbers are based on brands like Bud Light, Sierra Nevada, Blue Moon, and Guinness respectively. Of course, exact yields vary between specific brands and batches, but this gives a good rule of thumb.
Factors that increase beer yield
There are a few tricks both breweries and bars can use to increase the number of beers poured from one keg:
Overfill
Some breweries will intentionally overfill kegs. By putting 14-14.5 gallons in a “15 gallon” keg, they can eke out a few more servings.
High carbonation
Adding extra carbonation reduces the amount of liquid beer in a keg. While this can increase foam and waste, it forces more carbon dioxide into the space, allowing more beer to be dispensed overall.
Lower ABV
Using a lighter beer style with lower alcohol content like a lager or pale ale results in higher yields compared to heavier beers.
Reduce foam
Bartenders can pour and manage the beer to minimize excess foam. This keeps more CO2 in solution and reduces waste.
Factors that decrease beer yield
On the other hand, there are also some things that can reduce the number of beers poured from a keg:
Underfilling
Some kegs may be underfilled by breweries, containing only 12-13 gallons instead of a full 15. This immediately cuts down the possible beers.
High alcohol
Full-bodied beers with elevated alcohol like double IPAs will have lower yields than lighter beers, since they take up more liquid volume.
Excess foam
If beer is poured improperly allowing lots of foam, or there are issues with the tap system, the nitrogen or CO2 content gets depleted faster, reducing overall yield.
Spillage and waste
Sloppy bartenders and lots of spillage drives down the number of usable beers per keg. Waste should be minimized as much as possible.
Estimating beers needed for a party
Planning a keg party or bar event? Here is an easy guideline to estimate the number of 15 gallon kegs needed:
- Casual party: 1 keg per 40-50 people
- Semi-formal party: 1 keg per 30-40 people
- Formal party: 1 keg per 20-30 people
This accounts for factors like some people drinking more than others, different beer styles, and plenty of supply. When in doubt, it is better to have extra than run out! After factoring in the number of attendees and their drinking habits, use the standard beer yields above to calculate the minimum number of kegs required.
Keg size calculator
Here is an easy calculator to figure out how many beers you can get from different keg sizes. Just plug in the keg volume, beer style, and alcohol percentage – it will automatically estimate the number of 12 oz pours!
| Keg Size (gallons) | |
| Beer Style | |
| Alcohol Percent | |
| Number of Beers |
Try it out with different values to see how the yield changes!
Factors affecting cost
In addition to yield, several other factors affect the cost per beer from a keg:
- Keg deposit – Many breweries charge a deposit up front for the keg (e.g. $30) that is refunded when returned.
- Keg return procedures – Returning the keg properly can take staff time and gas for pressurization.
- Tap system – Bars require specialized tap systems to serve kegs which are an upfront investment.
- Refrigeration – Keeping kegs cooled to 38-42°F consumes electricity.
- Cleaning lines – Beer taps and lines need regular cleaning to avoid contamination.
- License fees – Bars must pay annual fees for a liquor license to serve alcohol.
While kegs may seem like an economical way to serve beer, there are many additional hidden costs involved that can drive up the effective price per pint. Kegs are more cost effective at large scale, but for smaller establishments, the costs of the associated infrastructure and operating expenses make bottled or canned beer more profitable.
Other common keg sizes
In addition to 15.5 gallon half kegs, there are several other common keg sizes used by breweries and bars:
Sixth barrel
At 5.23 gallons, a sixth barrel keg is the smallest commercial size. They are sometimes called “sixelts” or “sixtels.” These are convenient for smaller draft systems.
Quarter barrel
Quarter barrel kegs contain 7.75 gallons of beer. This size is commonly used for craft beers and at bars that go through different products quickly.
Pony keg
Pony kegs hold around 8.5 gallons. This non-standard size is primarily used by smaller craft breweries.
Half barrel
The half barrel is 15.5 gallons and the most common full-scale keg size. Half kegs are widely used for large parties or venues.
Keg tapping equipment
To serve beer from a keg rather than bottles or cans, you need some specialized equipment:
Keg coupler
Keg couplers connect the keg to the beer line and tap. Different couplers are required for the D, G, S, and A style keg valves from major manufacturers.
Beer line
Vinyl or stainless steel beer line carries beer from the coupler to the faucet. Lines are normally 5-10 feet long.
Faucet
A draft tower or faucet is needed to actually pour and dispense the beer. Commercial bars use specialized taps.
Drip tray
Drip trays attach to the draft tower to catch any overflow or spillage that occurs when filling glasses.
Refrigeration
Kegs need to be kept ice cold. Draft systems use glycol cooling systems or cold plates to chill beer lines and faucets.
Gas
CO2 or nitrogen gas is required to pressurize and propel beer through the lines to the faucet.
Kegging homebrew
With the right equipment, you can fill and serve kegs of your own homemade beer or soda. This enables you to enjoy draft beers at home.
Used kegs
It is possible to purchase used kegs that previously held commercial beers. Once cleaned, these can be reused for homebrew.
New kegs
Many homebrew supply shops sell new stainless steel kegs specifically intended for homebrewing in 5 gallon and smaller sizes.
Kegging equipment
Filling and tapping kegs at home requires a kegging kit consisting of hoses, valves, a cylinder, regulator, and likely a small CO2 tank. These allow you to fill, carbonate, and dispense the beer.
Counterpressure filler
A counterpressure bottle filler lets you purge, fill, and cap the keg while maintaining carbonation. This piece of equipment is essential for proper home kegging.
Pros of kegging
There are several benefits to beer in kegs compared to bottles or cans:
- Less oxidation – Kegs are purged of oxygen and sealed
- No light exposure – Kegs completely block light
- Better carbonation – Kegging allows precise CO2 levels
- Lower serving costs – No bottling/canning line needed
- Less storage space – Empty kegs stack efficiently
- Portability – Kegs are easy to move with dollies
With proper cleaning and handling technique, kegged beer can remain fresh and high quality for months.
Cons of kegging
However, there are also some downsides associated with kegging beer:
- High upfront cost – Kegs themselves are expensive
- Specialized equipment – Tapping requires an investment as well
- Short shelf life – Once tapped, kegs go stale within days
- No individual portions – Must finish a keg once opened
- Heaviness – Full kegs can weigh over 160 pounds
- Deposit hassle – Need to deal with returns for deposit refunds
Kegging makes the most sense for larger scale production and serving. Small breweries and homebrewers often find bottles or cans more convenient.
Keg FAQs
How long does an open keg last?
Once tapped, a keg will last 1-2 weeks at most before the beer starts to degrade in quality. With proper refrigeration and closed lines, open kegs can last up to a month before going stale.
How much does a keg weigh?
A full 15.5 gallon keg weighs about 160-170 pounds. The keg itself is 30 pounds, with the rest being liquid beer.
What is the PSI for keg beer?
Most keg beers are carbonated to 2.5-3 volumes of CO2. This equals a pressure of 11-14 PSI at 38°F beer temperature.
What pressure should a kegerator be set to?
Kegerators are normally set to 38°F and 12 PSI. Higher pressures can lead to overcarbonation and foam.
How much headspace should be in a keg?
Ideally a keg should have 4-6 inches of headspace above the liquid beer. This allows for proper carbonation.
Conclusion
While the exact beer yield from a 15 gallon keg depends on factors like the amount of overfill, foam, and waste, the typical full keg holds around 13.5 gallons of beer and will pour about 165 12oz servings. With proper line balancing, pouring technique, and fresh kegs, yields can reach up to 170 beers per half barrel. For planning parties, events, or just stocking a backyard bar, you can use these standard beer yields per keg to estimate your needs!