Beer Tube Screens: How Do They Work?

A beer tube screen is a crucial component of a kegerator or draft beer system, ensuring that the final product is free of sediment and other undesirable elements. These screens are typically made of stainless steel mesh and are designed to filter out trub, whole hops, and other particles from the wort during the brewing process. They are also used in mash tuns, boil kettles, and carboys for dry hopping. The screens come in various sizes, with some designed to fit specific containers, and they can be purchased online or from homebrewing shops. Understanding how these screens function is essential for maintaining a smooth and efficient draft beer system.

The role of a beer tube screen in a direct draw system

A direct draw beer dispensing system is a self-contained, thermostatically controlled refrigeration unit in which one or more kegs of beer are stored at an optimum temperature of 34-38° F. This system is the most common and straightforward draft beer system for delivering draft beer from keg to tap across a short distance. It is the top choice for bars with a beer keg located within a few feet of the beer dispensing faucet.

A direct draw beer system may be contained within a walk-in cooler, a commercial keg box, or within a kegerator or converted refrigerator. The faucet is directly connected to either a cooler box or a tower directly connected to a self-contained cooler. The beer kegs are stored, cooled, and tapped in the same cooler. The beer in the keg, beer line, and beer tower connected to the faucet are all chilled by circulated cold air.

The direct draw system offers the benefit of no hidden beer lines, making service and access easier. Due to the short length of the beer lines, there is also much less waste during the cleaning process.

In a direct draw system, carbon dioxide or a mixture of nitrogen and CO2, known as beer gas, is used to push beer from the keg through the beer line up to the draft tower and faucet. The beer line is typically 3/16" inside diameter (I.D.) and made from food-grade vinyl. It attaches directly to the coupler on one side and the shank or faucet on the other.

How beer is pushed from the keg through the beer line

A draft beer system is made up of a series of components that work together to pour a pint of beer. There are three standard systems for dispensing draft beer: direct draw, long-draw glycol cooled, and long-draw air-cooled. All three systems use similar pieces of equipment, but each has its own way of delivering or cooling the beer as it travels from the keg to the tap.

In any draft system, there are six main components: a cooler, keg, coupler, gas, tubing, and faucet. This is the basic setup, but the system can get more complex. These six pieces all work together to ensure that the beer served is properly chilled and carbonated, with an appropriate foamy head.

The keg is where the beer resides. Kegs come in a wide variety of sizes, shapes, and materials, but beer made in the US is usually packaged in 5-gallon, 7.75-gallon, or 15.5-gallon kegs made of stainless steel. From the outside, you can see a valve on top. This is where the gas flows in and the beer flows out. Inside the keg, there's a long tube of metal extending from the valve to the vessel's bottom. To get beer out of the keg, gas pressure is applied to the top surface of the liquid, which presses the beer from the bottom of the keg up through the tube and out of the valve.

The coupler is another piece of equipment that is used to open the valve. The coupler plugs into the top of the keg and has a little handle that you pull down to open the valve and start the flow of gas into the airspace of the keg. The coupler connects to two tubes: one brings gas to the keg, and one lets the beer flow out on its way to your glass.

Most bars and restaurants use canisters of pure bottled carbon dioxide and nitrogen to push the beer out of the kegs. A regulator allows the operator to control the amount of pressure leaving the tanks. The gas is pushed into the keg through the coupler, and it forces the beer out into the beer line, where it eventually travels up to the tap so you can pour a pint.

On the trip from keg to faucet, beer travels through vinyl or polyethylene tubing measuring about a quarter of an inch in diameter. In systems where the beer has a long distance to travel from keg to tap, this tubing may be chilled to ensure the beer stays cold.

The last piece of equipment standing between you and your beer is the faucet. Here, you run into another valve, which is controlled by pulling the tap handle. The tap needs to be opened completely (by pulling the handle all the way forward), or you'll create turbulence that will cause foaming in the glass.

The function of a coupler

A keg coupler, also known as a keg tap, is an essential component of a kegerator or draft beer system. It connects the keg to the beer tap system, allowing beer to flow from the keg to the tap and enabling the perfect pour.

The coupler consists of various components, including the probe, handle, pressure relief valve, and check valve. The probe is inserted into the keg valve, piercing the keg's diptube, which extends to the bottom of the container. The handle is then used to engage the keg's valve, securing the coupler in place. The pressure relief valve prevents over-pressurization by releasing excess pressure, while the check valve permits the flow of beer when the tap is opened and prevents it from flowing back into the keg when closed.

There are several different types of keg couplers, each designed to fit a specific type of keg valve. The most common type is the D-Type or Sankey keg coupler, which is used for most North American beers, including Budweiser, Coors, and Miller. The S-Type coupler is used for European Sankey kegs, such as Heineken and Stella Artois, and has a longer probe than the D-Type. The G-Type coupler is used for German beers, including Warsteiner and Paulaner, and has a unique probe that fits a keg valve with a threaded opening. The U-Type coupler is used for some European beers, including Guinness and Harp, and is also known as a European Sankey coupler.

It is crucial to use the correct coupler for the specific beer and keg valve to ensure proper beer flow, carbonation, and dispensing. Using the wrong coupler can result in a poor pour, excess foam, or even damage to the keg or coupler. Therefore, it is important to identify the brand/style of beer, its origin, and the size of the keg to choose the right coupler.

The importance of a regulator

A regulator is a crucial component of a kegerator, controlling the flow of gas (usually CO2 or nitrogen) from the cylinder to the air tube. It ensures the gas is delivered at a consistent and appropriate pressure, which is vital for maintaining the carbonation level and overall quality of the beer.

Regulators are essential for several reasons:

Carbonation Control

The level of carbonation in beer affects its taste, mouthfeel, and presentation. Different beer styles require different carbonation levels, and regulators help maintain the desired level for each style.

Consistent Quality

Inconsistent gas pressure can lead to over or under-carbonated beer, impacting its quality. Regulators ensure that the beer maintains its intended flavor and texture from the first to the last pour.

Safety

Handling pressurized gases can be dangerous. Regulators mitigate this risk by controlling gas pressure, preventing accidents like keg explosions or gas leaks.

Primary Regulators

Primary regulators are directly connected to the gas tank, reducing the high pressure of the gas to a more manageable level. They typically feature one or two gauges: one showing the pressure of the gas being released (PSI) and the other displaying the remaining pressure in the tank. Some primary regulators also have a pressure relief valve (PRV) to prevent over-pressurization.

Secondary Regulators

Secondary regulators are used when multiple kegs require different gas pressures. They are connected downstream of the primary regulator, allowing individual pressure adjustments for each keg. Unlike primary regulators, they do not connect directly to the gas tank.

Choosing the Right Regulator

When selecting a regulator, consider the type of gas (CO2 or nitrogen), the number of kegs being served simultaneously, and the specific pressure requirements for each beer. It is also advisable to choose a high-quality and durable regulator due to its critical role in the brewing process.

The purpose of a glycol chiller

A glycol chiller is a specialised refrigeration system that uses a glycol-water mixture as a coolant. Glycol is a class of organic compounds that belong to the alcohol family and helps slow the rate of freezing. The most common glycol-water ratio is 60/40, which is the optimal combination to maximise the mixture's antifreeze properties.

Glycol chillers are often used to cool liquids, including alcohol and other beverages. They are particularly useful in the fermentation process, where they help maintain a steady temperature. This is important as fermentation generates heat. They can also be used to cool the wort after the initial boiling process or to crash cool beer after fermentation.

Propylene glycol, a food-grade antifreeze, is typically used when consumable products are involved. It is non-toxic, making it the safest option for breweries, food processing, and dairy, among other industries.

Glycol chillers offer several advantages, including consistent cooling temperatures, higher-quality food, and the ability to accommodate a narrow temperature range. They are also energy-efficient, with options such as a glycol economiser and EC condenser fans.

Frequently asked questions