Types of Draft Beer Systems

Serving beer on tap has a long tradition that started with hand-pumping beer from wooden barrels. Since the mid-1900s, when beer began to be served from pressurized containers and carbonated with CO₂, several draft (or "draught") beer systems have evolved to meet bartenders' needs.

There are three common technologies built for serving beer on tap: direct draw, air cooled, and glycol systems. This article will discuss these three draft beer systems, along with the benefits, drawbacks, and recommendations for which system will work best for your operation.

Why Draft Beer Systems?

Draft beer keeps beer cold and fresh. Beer from kegs should be served at 38 degrees Fahrenheit to maintain the right carbonation and best taste.¹ If it gets too warm on its way to the tap, it will release CO₂ prematurely, losing some of its carbonation. This affects the beer's flavor and produces too much foam.

If the beer gets too cool, however, it won't release enough CO₂, preventing a foamy head from developing and causing CO₂ to release in the customer's stomach after consumption. Additionally, very cold beer will numb your customers' taste buds. Draft beer systems are intended to keep beer at the proper serving temperature from the keg to the tap.

Draft System 1: Direct Draw

Direct draw systems are the simplest and most cost-effective beer draft systems. They implement methods like keg boxes or beer walls. Keg boxes—also called kegerators—are back bar coolers with a beer tower mounted on top. Most can only accommodate a few half-size kegs and one to four taps.

Beer walls can hold many taps along the back wall of a bar. To set up a beer wall, operators must install a walk-in cooler directly behind the back wall of the bar. From there you can drill holes through the wall and connect shanks or shadowboxes to feed the beer from the kegs to the taps. This results in dozens of beer taps that come directly from the walk-in cooler.

Pros of Direct Draw Systems:

• Simple setup without installing long beer lines
• Economical cost
• Kegerators are easy to add to tight spaces
• Wall-mounted beer taps provide a unique bar setting

Cons of Direct Draw Systems:

• Limited product capacity in back bar kegerators
• Beer taps must come directly from the walk-in cooler

Draft System 2: Air-cooled Design

Air-cooled designs require more intricate setups. Like the beer wall method, beer kegs are stored in a dedicated walk-in cooler, but each keg connects to a line running out to beer towers on the bar for remote access.

Here's how it works:

The beer lines are encased in an insulated duct; a fan within the walk-in cooler pushes chilled air through this duct and all the way to the beer tower. Then, a special valve allows the cold air to flow around the tower where beer is dispensed and return to the walk-in cooler, either through a larger tube encasing the "cold" beer duct or a separate duct traveling back to the walk-in cooler. This creates a closed system that cools the beer all the way to the tap.

The line is limited to 25 feet, since the cold air can only travel so far before heating up; it's also usually restricted in the number of taps it can accommodate.

Pros of Air-cooled Systems:

• Can source beer remotely up to 25 feet
• Keeps beer chilled all the way to the tap
• Cheaper than glycol systems

Cons of Air-cooled Systems:

• Limited to short beer line lengths
• Limited number of taps

Draft System 3: Glycol Lines

Glycol systems are the most complex, versatile, and expensive type of draft beer system. They work similarly to air-cooled long-draw systems but can be stored hundreds of feet away from the tap. Each beer line is fed into a glycol trunk line that then runs either under the floor or in the ceiling until it reaches the tap.

Within the glycol trunk line, there will be a few glycol lines surrounded by beer lines. Some trunk lines house up to 16 beer lines. These are then insulated and wrapped with a foam cover to keep the line cool.

Glycol, a synthetic liquid with a low freezing point, travels from a power pack that cools it, through the trunk line, and into the beer tower, all the way to the beer dispensing point. The power pack cools the glycol to a temperature lower than 38 degrees Fahrenheit, so as it heats up due to friction against the tube, it will maintain beer at the ideal temperature. From there, the glycol returns to the walk-in cooler for rechilling in the power pack. Glycol systems sometimes use a mixed gas of CO₂ and Nitrogen to displace the beer in the kegs. This "beer gas" allows beer to retain its carbonation and temperature while being dispensed.

Pros of Glycol Systems:

• Can source beer from kegs located several hundred feet from the tap
• Large tap capacity
• Multiple tap locations from one walk-in can serve multiple bars

Cons of Glycol Systems:

• More maintenance required
• Higher cost

Other Types of Beer Tap Systems

Although these are the three industry-standard systems for cold draft, temporary draught beer systems include hand pumps and jockey boxes. Hand pumps use either compressed air or CO₂ canisters to force beer out of a single tap connected to the top of a keg. Jockey boxes flash chill beer by running the beer line through an ice box or cold plate. Both options are meant for temporary use, as exposing the keg to room temperature or compressed air will impact the beer quality over time.

Choose a Draft Beer System to Match Your Bar Style

Direct draw systems using kegerators are ideal for small operations offering limited selections. They're also more budget friendly since they don't require a dedicated walk-in cooler.

If you can afford the space and price of a walk-in cooler, beer walls enable you to offer dozens of taps in one place. You'll be limited as to where you can put these taps, but you'll save money by eliminating the need for long beer lines.

Air-cooled systems are good for operations with remote access to a walk-in cooler. While many air-cooled systems have been replaced with glycol systems, the cheaper price point may be attractive to smaller operations that can't offer direct draw.

Glycol systems are the most versatile options. They're best for large bars, breweries, or pubs, and they can serve numerous taps in multiple locations from one dedicated walk-in cooler. You can also create stylish beer tower designs for serving craft beer.

Find draft beer replacement parts or get help designing your own draft beer system at KaTom.com.

References

1. Draught Beer Quality Manual. Brewers Association. Accessed April 2025.