The amount of beer that a keg holds can vary depending on the size and style of the keg. Most commercial kegs that you would find at a bar or restaurant hold either a half barrel or a sixth barrel of beer. Here are some quick answers about how much beer is in common keg sizes:
Half Barrel Keg
A half barrel keg holds 15.5 gallons of beer. This is the most common keg size for commercial draft systems in bars and restaurants in the United States.
Amount of Beer
15.5 gallons of beer
Amount in Ounces
1984 ounces of beer
Amount in 12 oz Beers
165 12-ounce beers
Sixth Barrel Keg
A sixth barrel keg holds 5.23 gallons of beer. This size keg is also commonly used for commercial draft systems.
Amount of Beer
5.23 gallons of beer
Amount in Ounces
664 ounces of beer
Amount in 12 oz Beers
55 12-ounce beers
Quarter Barrel Keg
A quarter barrel keg is half the size of a full barrel and holds 7.75 gallons of beer. This size keg may be used for some commercial draft systems but is more common for homebrew kegerators.
Amount of Beer
7.75 gallons of beer
Amount in Ounces
992 ounces of beer
Amount in 12 oz Beers
82 12-ounce beers
Slim Quarter Keg
Slim quarter kegs are shorter and slimmer than a standard quarter barrel. They hold 6.92 gallons of beer.
Amount of Beer
6.92 gallons of beer
Amount in Ounces
882 ounces of beer
Amount in 12 oz Beers
74 12-ounce beers
Cornelius Keg
Cornelius kegs, also known as Corney kegs, are stainless steel soda kegs that are commonly reused by homebrewers. They hold 5 gallons of beer.
Amount of Beer
5 gallons of beer
Amount in Ounces
640 ounces of beer
Amount in 12 oz Beers
53 12-ounce beers
Pin Lock Keg
Pin lock kegs are smaller Cornelius style kegs that hold less beer. The standard pin lock keg size is 3.5 gallons.
Amount of Beer
3.5 gallons of beer
Amount in Ounces
448 ounces of beer
Amount in 12 oz Beers
37 12-ounce beers
Mini Keg
Mini kegs are smaller kegs designed for personal, non-commercial use. Standard mini keg sizes include:
- 5 Liters = 1.32 gallons = 169 ounces = 14 12-oz beers
- 10 Liters = 2.64 gallons = 338 ounces = 28 12-oz beers
Factors That Affect Amount of Beer in a Keg
There are several factors that can affect how much beer a keg actually contains:
Overfill
Some breweries or distributors may overfill kegs, providing up to 10% more beer than the standard amount. This is done to ensure sufficient pressure is achieved for pumping the beer.
Underfill
On the other hand, some kegs may be slightly underfilled to allow room for foam and proper carbonation.
Different Keg Styles
There can be variations in capacity between different keg manufacturers and styles, such as European kegs compared to American kegs.
Short Pours
Spilled beer, foam overflow, or distributing samples from the keg can decrease the actual amount of beer remaining compared to the starting volume.
Measuring How Much Beer is in a Keg
Since the actual amount of beer remaining in a keg can vary, there are a few common methods for measuring or estimating the remaining volume:
Weighing the Keg
Weighing the keg periodically can help estimate how much beer is left. 1 gallon of beer weighs about 8.3 lbs. Knowing the starting weight and subtracting the current weight gives the weight of beer removed, which can be divided by 8.3 to get gallons remaining.
Measuring Remaining Liquid
A measuring stick can be inserted through the opening of the keg to determine inches or gallons remaining in liquid form.
Keg Pressure Gauges
Special keg taps with built-in pressure gauges can measure psi to estimate how full the keg is. This is based on the principle that more air pressure is required to pump beer from a near-empty keg.
Flow Meters
Flow meters installed on the beer line measure each pour and calculate exactly how much beer has been dispensed from that keg.
Floating Dip Tubes
Floating dip tubes rise up along with the beer level, allowing the pickup tube to remain submerged in beer until the keg is empty.
Tapping a Keg: Step-by-Step Process
Once you have your keg, here is a typical process for tapping it and serving the beer:
- Chill the keg – Kegs should be stored and served cold, between 38-42°F for optimum flavor and carbonation.
- Connect the CO2 – Hook up the CO2 regulator and gas line to the keg coupler inlet to pressurize the keg. Set PSI between 10-15 psi depending on beer style.
- Purge the oxygen – Briefly open the coupler valve to release oxygen and fill the headspace with CO2 before tapping.
- Tap the keg – Attach the coupler over the keg valve opening and turn to secure it.
- Check for leaks – Listen and look for any leaks where gas is escaping.
- Pull the relief valve – Vent any initial foam through the coupler relief valve.
- Pour beer! – Pull the tap handle to pour chilled, carbonated beer.
Remember to maximize keg freshness by keeping it cold and sealed when not serving. Replace the CO2 as it runs out. Follow careful sanitation practices and maintain proper system pressure.
Serving Beer from a Keg
Once tapped, kegged beer should be dispensed using these guidelines for the best drinking experience:
Use CO2 or a Beer Pump
Always use forced carbon dioxide or a beer pump to dispense keg beer. Do not attempt to pour from the keg opening.
Maintain Proper Pressure
Set the CO2 or pump pressure between 10-15 PSI for a smooth pour with proper carbonation. Higher pressure risks over-carbonation.
Minimize Exposure to Oxygen
Try to limit oxygen exposure by keeping the keg cold and sealed whenever possible. Purge keg headspace with CO2 if needed.
Clean Lines Regularly
Dirty beer lines can lead to off flavors or contamination. Clean all equipment regularly.
Watch for Foaming
If foam starts building up, pause the pour or vent using the coupler relief valve.
Avoid Temperature Fluctuations
Big temperature swings can affect carbonation levels and cause foaming issues.
Store Kegs Properly When Not in Use
Keep unused kegs refrigerated and sealed. Do not leave beer sitting in tapped kegs at room temp.
Troubleshooting Common Keg Problems
Some common issues that can arise when tapping and pouring kegged beer include:
Too Much Foam
Excessive foam may be caused by high system pressure, dirty lines, improper temperature, or agitation of the keg. Adjust PSI, clean equipment, chill keg, and handle keg gently.
Not Enough Carbonation
Flat beer can result from low CO2 pressure, empty CO2 tank, leaking connections, or serving at too warm of a temperature. Increase PSI to 12-15 range, refill CO2 as needed, and keep keg chilled to 38-40°F.
Bad Flavors
Off tastes or smells may indicate dirty lines or a contaminated keg. Use beer line cleaner and replace kits as needed. Sanitize all equipment.
No Beer Flow
If no beer flows when the tap is opened, the coupler connection may be loose, gas and beer lines reversed, or the keg may be empty. Check connections, line order, and measure beer level.
Slow Beer Flow
Slow pouring speed can result from low pressure, clogged lines, excessive line length or wrong line diameter. Increase PSI, clean lines, reduce length, and ensure 3/16″ ID tubing.
Keg Size Comparison Table
| Keg Size | Total Gallons | Total Ounces | 12 oz Beers |
|---|---|---|---|
| Half Barrel | 15.5 gal | 1984 oz | 165 beers |
| Sixth Barrel | 5.23 gal | 664 oz | 55 beers |
| Quarter Barrel | 7.75 gal | 992 oz | 82 beers |
| Slim Quarter | 6.92 gal | 882 oz | 74 beers |
| Cornelius | 5.0 gal | 640 oz | 53 beers |
| Pin Lock | 3.5 gal | 448 oz | 37 beers |
| 5 L Mini Keg | 1.32 gal | 169 oz | 14 beers |
| 10 L Mini Keg | 2.64 gal | 338 oz | 28 beers |
Conclusion
Keg sizes can range from large 15.5 gallon commercial kegs to smaller 5-10 liter kegs for personal use. The most common full size kegs are half barrel and sixth barrel, holding over 150 and 50 twelve ounce beers respectively. Many factors can affect the actual amount of beer remaining in a tapped keg. Weighing, measuring, or using a keg meter are the best ways to monitor how much beer is left. Follow proper tapping, storage, and serving procedures to get the most out of your kegged beer.