What is a Beer System?

What is a Beer System?

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Bartender Pouring draft beer from a draft beer system

Walk into almost any establishment today, and you will likely see draft beer being served.  It is so common we do not think about what it means to install, service, and operate a draft beer system.


Draft Beer Systems

“What is a draft beer system exactly?” and “What is a draught beer system?” These are two questions we frequently answer because people have some idea, but don’t fully know the complexity of a system.  Not that our customers are dumb or ignorant, it’s just not important in their day-to-day operations.  However, having a better understanding of the equipment and process will allow prospects and customers to make better decisions when specifying a draft beer system.  This will typically lower costs, as the client can better schedule time and resources by having more information during an installation.  Additionally, the process may run smoother as the customer is more informed.

“We don’t think of the complexity behind the wall required to serve the perfect pour every time.”

This article will give a brief overview of the major components that make up a draft beer system or a draught beer system, and how they work together.

There are 3 Major Sub-Systems in Most Beer Systems

There are 3 sub-systems which are common to most draft beer systems.  These include the gas required to dispense the beer; the beer itself (from the familiar to the specialty craft options available); and, the cooling options needed to maintain the correct temperature for storage and consumption.

#1 – The Gas

There are several types of gas and delivery options, but Gas usually serves two purposes.

  1. It maintains the correct carbonation while helping to preserve the proper flavor.
  2. Moreover, it pushes or propels the beer from the keg to the tap.

Types of Gasses

Gasses are food grade and highly regulated for purity and consistency because they come into direct contact with the beer during storage and consumption.


C02 is the most common gas and is often use alone or in combination with other gasses.  As the most common Gas, C02 is often blended based on the system architecture or type of beer being served.


The most common blend gas is nitrogen (N2). Nitrogen is commonly mixed with C02 and is always show second when combined with C02 as a blend gas.


Blend gasses are manufactured locally on-site, or delivered to a facility pre-blended.  The formulations vary widely and can be almost limitless. The blend ratio is determined by the product being served.

Compressed Air


Compressed air should never be specified when installing a beer system.  It introduces impurities and moisture to the beer. It will ruin the flavor and spoil the beer.


#2 – The Beer

The drive in keg cooler at Legal Draft, Arlington TX The drive in keg cooler at Legal Draft, Arlington TX, showing the 40 tap system powered by a Micro Matic Pro-Line Glycol Power Pack. The trunk line is the thick black line on the right half of the back wall.

Most draft beer moves from the keg to the glass through tubing. Gas powers the movement of the beer from the keg to the faucet through a series of tubing.  Flexible tubing is specified today due to its ease of installation and labeling. Stainless Steel is also an option in some applications.

Different types of draught beer require different delivery systems.

Beers come in various types such as Ales, Lagers, Stouts, Porters, and Malts.  There are several different styles of beer also.  These include Amber, Blond, Brown, Cream, Dark, Fruit, Golden, Honey, India Pale Ale, Light, Lime, Pale, Pilsner, Red, Strong, and Wheat.  With this number of combinations, specifying the correct draft beer system is paramount.

#3 – The Cooling

The Micro Matic Pro-Line Glycol Power Pack The Micro Matic Pro-Line Glycol Power Pack showing the 29-degree temperature they system is able to maintain. This workhorse unit can support trunk lines of 250 feet and is a dual motor dual pump unit supporting 40 taps.

The cooling system is as critical as the beer and the gas. A cooling system maintains the beer at a constant temperature during storage and delivery to the faucet.  The cooling system consists of a refrigerated storage area or container to hold the draught beer kegs.

If the beer is dispensed close by (Direct Draw Beer System), that may be all that is needed. If the delivery location is farther away (Long Draw Beer System), cooling the delivery lines may also be required to maintain the optimal temperature of the beer. This keeps beer cool all the way to the glass.

If there is a difference in temperature from keg to faucet, problems with dispensing such as foaming may occur.


Components Common to Beer Systems

We have covered the 3 main sub-systems. Now, let’s take a look at the components required to assemble the 3 sub-systems into a draft beer system.  There are about 9 individual components needed to complete a typical draft beer system.  Additionally, we will look at the important parts of each component.

  1. Refrigeration / Cooling

Beer should be between 340 and 380 F from the keg to the glass. Temporary installations may use ice while permanent installations typically require a refrigeration system to maintain the proper temperature.

  1. Self-contained cooling

For small temporary installations, self-contained cooling may only consist of an ice/water bath in a large trash can.  Locally mounting a compressor and condenser is more typical in permanent installations. This compressor/condenser combination may be unique to the beer system or shared among multiple disciplines such as using a walk-in cooler to store beer and food products.

  1. Remote mounted compressor and condenser

A remote mounted compressor and condenser is an option when retail space is limited.  By installing the compressor and condenser remotely, limited space in the facility is utilized efficiently.  Additional plumbing may be required to connect the remote systems with the local beer delivery.

  1. Condenser Cooling Types

There are two types of cooling types, air, and water.  Each offers distinct benefits.

  1. Air-Cooling – Air-cooling is typically less expensive and easier to service and maintain.
  2. Water-Cooling – Water-Cooling requires both a source and drain for the water supply.  Water-cooling is more costly to install and maintain due to the added complexity of the cooling system.
  1. Keg

A keg is a pressurized container holding a specific amount of beer. Most kegs are made of stainless steel or aluminum. Plastic and rubberized containers are also becoming more popular in the industry depending on size.

All kegs are pressurized. “Tapping a keg” refers to attaching a connector to the keg neck and applying some form of gas to the keg, on top of the beer, to push it down and out the pickup at the bottom of the keg. The beer flows up the internal tube inside the keg and exits through the same keg neck connection.

5 common keg sizes are range from approximately 5 to 15 gallons.  Weight per keg can be from 58 to 160 pounds when full. Keg sizes also are rated in the number of 12oz. glasses of beer they hold.

  1. Couplers

The coupler is the physical connector that “Taps” the keg.  It allows gas to flow into the keg and beer to flow out of the keg. There are several different types of couplers available, and your installer will specify the correct one for the beer you plan to serve.

The most common connector type from US Distributors is the “Sankey D Coupler”.  Specialty and craft breweries may specify alternatives.

There are several safety features to keep the gas flow going into the keg and beer exiting the keg. One-way valves maintain the flow going in the correct direction. Check valves prevent gas or beer from flowing freely once the connector is disconnected. A pressure relief valve on each connector acts as a safety to keep the pressure inside the keg from building up to unsafe levels.

  1. Beer Line

The beer line is the medium beer travels through from keg to faucet.  Options range from vinyl and barrier tubing to stainless steel. Depending on the application and the length the beer travels from keg to glass determines the type of beer line specified. Vinyl beer line is inexpensive, flexible, and the most common. Installers use Barrier Tubing where the distance from keg to the faucet is longer. Stainless Steel is specified when the keg to tap distance is relatively short due to its added expense. Draft Beer systems incorporate one or all of the different beer line tubing types in a single installation based on requirements.

  1. Faucets (Taps)

Beer faucets are the customer-facing portion of the beer system. Commonly referred to as “Beer Taps. ” The faucets come in several designs, and each has pros and cons of the type of beer being dispensed. They typically have a tall handle with the name of the beer prominently displayed on each tap.

There are standard and European faucets in several configurations. Front sealing, rear sealing, vented and ventless faucets are available with and without flow control. Some faucets are specifically designed to pour nitrogenated beers or stouts. There are faucets to cream the beer (add bubbles) to achieve the proper texture for the beer.


Additionally, there are several faucets, which can dispense products other than beer such as wine, whiskey, coffee and other beverages.

Faucets are complex devices often made up of multiple parts and pieces to achieve the desired result. Pro’s and con’s of each faucet design must be weighed against the desired result to obtain the proper pour before the faucet is specified.

  1. Gas Source

NOTE:  Never use compressed air as a gas source for beverages due to oxygen spoiling anything it contacts, and contaminants pushed into the product.

To dispense beer there needs to be some way to push it out of the keg, through the beer line and faucet, and into the glass. Gas is the source used for this purpose. The gas source is either carbon dioxide or a carbon dioxide nitrogen mix.  Both types of gas are oxygen free.

This gas is beverage grade and meets stringent requirements to achieve the purity of the beverage grade label. Food grade gas keeps from imparting impurities, spoiling the beer, or altering the flavoring the beer.  Purity is also required to keep from ruining the beer.

Retailers purchase beverage-grade gas canisters directly and change them out as they become empty. For higher volume operations, gas is dispensed and refilled from a holding tank (Dewar) installed on location.

Gas is stored under high pressure and requires proper measures to ensure safety.  Atmospheric vents prevent the buildup of gas in confined spaces.  Safety alarms signal when leaks or gas concentration exceed a certain level.

The gas source can power both soda and other beverages along with beer.

  1. Gas Line

The gas line connecting the gas source to the draft beer system is under pressure and the gas line specified must meet the pressure requirements of the draft beer system. Gas lines often require a thicker heavier duty vinyl tube or a braided vinyl tube due to the pressure required for the beer system. Using colored tubing helps differentiate the beer line tubing from the gas source when installing and servicing a draft beer system.

  1. Regulators

Every beer system requires regulators.  There is at least one regulator on the gas source.  This regulator often uses two gauges; one gauge to show the pressure in the tank and, a second gauge to show the regulated flow pressure.

Many regulators incorporate shut off valves to stop the flow of gas without adjusting the regulator. Regulators now come equipped with safety relief valves to prevent unacceptable gas pressure build up.

Micro-Matic Manifords Panels and Gas Feed This view is the interior of the Walk-In Cooler showing RSI’s clean and well organized installation of the Micro-Matic Long Draw Beer System including the Manifolds, Gas Distribution Panel, FOB’s, and Keg Feeds.[/caption]

Nitrogen regulators differ from carbon dioxide regulators operate at higher pressures. To differentiate them from carbon dioxide regulators they have male threads and a conical fitting which carbon dioxide regulators do not have. Additionally, in multi-gas beer systems, different colored regulators quickly identify the gas source type.

There are three types of pressure in draft beer systems:

  1. Atmospheric Pressure (psi)
  2. Dispense Pressure (psig)
  3. Absolute Pressure (psia)

Absolute pressure is the total pressure acting on the beer system. It is determined by adding atmospheric pressure to dispense pressure. It usually consists of atmospheric pressure, determined by altitude, plus the additional pressure applied by the gas applied to the beer system.

Most regulators display pressure on their gauges in “gauge pressure” or “psig” which is the dispense pressure. Beer system regulators are typically set to dispense pressure.

  1. Tail Pieces and Connectors

Each component of a draft beer system is connected using special connectors and tail pieces.  These connectors connect vinyl tubing to other beer system components.  They also connect different sizes of tubing together where needed. The connections are chrome plated, stainless steel where they contact with the beer.  This keeps the connectors from altering or adding a metallic flavor to the beer.

Stainless steel is inert and the recommended material for beer systems as it does not alter the flavor of beer.  Chrome plated connectors and tail pieces can lose their plating over time due to beer flow or the abrasiveness of cleaners used in the system.

END CONCLUSIONS — Components Common to Beer Systems

We have determined there are 3 sub-systems common to all draft beer systems.  These are gas, beer, and cooling.  These 3 sub-systems require several types of components to assemble into a draft beer system.

Some form of compressed gas powers all draft beer systems. It can be a single element gas or blended gasses. The system configuration and beer type determine the gas used and dispensing method. System volume determines the delivery method of the gas. Replaceable single canisters are used for low volume systems while refillable holding tanks are used for larger systems. Also, gasses are manufactured on site when necessary.

There are several types of beer with more options available frequently.  The typical beers from the large distributors have been around for some time and are served almost everywhere. Craft beers are extremely popular, and new varieties become available almost daily. Each beer is different and requires a delivery method specific to the type of beer. These factors may be beer type, beer weight, carbonated gas required, volume, or a combination of all the factors.

Keeping the beer at the proper temperature from keg to glass is a critical element in the design of any draft beer system and requires special consideration depending on the distance the beer tap is from the keg. Additional factors are whether the system is air or water-cooled and whether the evaporator and condenser are located in the cooler or remotely.

In addition, we describe each of the 9 major components required in all draft beer systems and provide an overview of their use and place in the beer system. Additional components are used in different beer systems configurations, but some form of these 9 components is required for all draft beer systems.

All these considerations must be taken into account when designing the proper draft beer system to provide your customers with the perfect pour of draft beer every time.