Draft System Overview (Provided by Summit Brewing Company)
There are three main types of draft systems.
1. Direct Draw – Kegs are stored directly underneath the taps, not in a remote cooler. This system generally holds from 1 to 5 kegs and is easy to clean. Bar supplies should not be stored in the unit because the constant opening of the doors can warm the unit and cause excess foaming.
2. Air Cooled – The beer is stored in a walk-in cooler and air from the cooler is circulated from the cooler to the taps via a tube, this cooling the beer lines and taps. This system should never be used in runs over 25 feet. The air-cooled system is very common and works well if installed and maintained correctly. Cooler temperatures (38°F) are critical.
3. Glycol Bath – A “power pack” refrigeration unit pumps food grade glycol through a trunk housing or “python.” The trunk housing contains beer lines wrapped in foam insulation. The glycol lines also run directly to the tower and faucets for cooling. Glycol systems have become increasingly popular in the United States. Their ability to keep beer cool for long distances (up to 500feet) makes them a very versatile system.
Draft System Maintenance:
Preventative maintenance keeps your system running well and problems at a minimum. The two most critical aspects of maintenance are making sure your cooling system continues to operate efficiently and cleaning your lines regularly.
Temperature – Temperature is critical to the quality of your beer. It will affect how it pours, looks, smells and tastes. Keeping your cooler at 38°F is always best. TIP –Put a thermometer in a glass of water and place this in your cooler to determine the actual temperature of your beer.
If you are using a glycol system, the power pack or glycol bath reservoir should be filled with the proper mix of glycol – usually 2 parts water to 1 part glycol. Distilled water is recommended. The temperature of the glycol should be maintained at approximately 29 to 30°F. To keep the system operating efficiently, keep grease and dirt from building up around the fan and remove any airflow obstructions. Fan blades in walk-in coolers should be cleaned whenever build-up is noticed. Remember: Always shut the unit off before attempting to clean.
Line Cleaning – No matter how well you tend your beer, if the lines are not clean, you will never pour the perfect pint, and you will lose sales. Lines should be cleaned every 7 days. Cleaning MUST include the removal and manual cleaning of the faucets and couplers.
Current research shows the old “fill and soak” method of line cleaning is not the most effective. In fact, by using a pump system and creating a rapid, turbulent flow, the cleaning effect is 80 times greater. Whether you are cleaning your own lines or contracting with a professional line cleaning service, the investment in a pump system will be money well spent. At Summit brewery, we clean our lines every 7 days using a sodium hydroxide cleaner. Every fourth cleaning we switch to a phosphoric acid cleaner to remove beer stone. Always circulate your cleaner for a minimum of 10 minutes and rinse the lines thoroughly with clean water when finished.
Gas Control Issues
Gas has two jobs in a draft system: To maintain carbonation and to push the beer out of the keg. The two main gases used in brewing are CO₂ and nitrogen. CO₂ is an ingredient in all beers. It affects flavor and appearance. The volume of CO₂ in beer is determined by the brewery and based on the style being brewed. Typically, American lagers have between 2.6 and 2.8 volumes of CO₂, while a stout’s volume could be as low as 1.2 to 1.8.
Beer is pushed by applying gas pressure to the keg, usually either by CO₂, nitrogen, or a blend of both. When beer is pushed with straight CO₂ the amount of pressure used to push the beer should be approximately 13 to 15 psi. However, when the pressure on a keg is turned up to 16 to 17 psi, or even 20 psi, the beer will start to absorb the CO₂ and in time, over-carbonate. Waste on an over-carbonated keg can be anywhere between 2 to 15%. This means that with the average wholesale cost of a keg around $100, the loss per keg can be around $2 to $15. If you are having problems with foam, switching to a blended gas may be an option. Nitrogen is the perfect choice as a second gas. It is 100 times harder to dissolve in beer than CO₂. By blending CO₂ and nitrogen, you can have the 13 to 15 psi of CO₂ needed to maintain carbonation and push the beer with the nitrogen at about 20 psi.
CO₂ and nitrogen are usually supplied in cylinders pressurized to hundreds of pounds per square inch. If you were to rupture a cylinder, the result could be fatal. For that reason always handle gas cylinders with extreme care. Store them upright and chained or secured to the wall. The gas pressure in your system is controlled by a regulator attached to the gas cylinder. Never try to by-pass the regulator and go directly to the keg. This can rupture the keg and could prove fatal. For more information on handling gases, contact your CO₂ provider.
A word of caution: Often, a well meaning proprietor will reduce over-carbonation simply by replacing CO₂ with “Guinness Blend,” which is approximately 70% nitrogen and 30% CO₂. This gas is great for nitrogenated products like Guinness, but will, in time, destroy the flavor and head on most other styles of beer. After only 5 days, a 30% CO₂ blend will cause most beers to look flat.
The simplest and most cost-effective way to change over to a gas blend is to install a blender box. Your beer will pour and taste better, and you will avoid the high expense of pre-blended tanks. A blender box can also be used to replace outdated compressed air systems. Contact your brewery rep or distributor for more information.
Remember: CO₂ and nitrogen both displace oxygen and can be deadly. If you suspect a leak, ventilate the cooler before entering and call your CO₂ provider.
Summit, along with most major U.S. brewers, agrees that air should NEVER be used to push beer. Air will destroy the flavor and integrity of beer.
Troubleshooting tips
If prepared you can quickly solve many problems with your draft system by following these troubleshooting tips.
FOAMY OR OVER-CARBONATED BEER – Is the cooler set at 38°F? If the keg has just been delivered, is it warm? If you have a glycol system, is it running? Is the glycol reservoir full enough to cover the coils? Is the glycol warm? It should be at approximately 28° to 30°F. Did you open the tap all the way?
NOTHING HAPPENS WHEN YOU OPEN THE TAP – Is the keg empty? (Sounds like a stupid question, but check it anyway.) Is the keg coupler connected properly? Are you out of CO₂ or nitrogen? Are the valves open on the gas cylinders? Is the regulator frozen? If so, pour some warm water on it and check for leaks. Is a fob stuck?
LITTLE HEAD OR FLAT BEER—Did you use a “beer clean,” cool glass? Rinse the glass and try again. If the beer pours better, check your dishwasher. Did a batch of glasses get washed with the posts and pans, thereby picking up head-destroying grease? If the beer still pours flat, check your CO₂ or gas blend. Is it set too low (below 12 psi)? Is the beer being poured correctly? Rinse glass with cold water and place it at an angle about 1 inch below the faucet. Open the faucet all the way. When the glass is about half full, tip it to an upright position. Now, let the remaining beer pour directly down the middle of the glass. This should insure the desired 1 inch head. When the glass is full, close the faucet quickly. Lastly, how old is the keg? Try a new one.
BEER TASTES “OFF” –When were the lines last cleaned? Summit Brewing recommends cleaning every 7 days. Is your glassware really clean? If you have an air blender system (which is NEVER recommended) you may have dirty filters in the compressor or water in the tank. Air in the tank can become contaminated by food odors, cleaners, pest control and bacteria. The only true way to correct this problem is to change the system over to a gas blender box and remove the air blender system. Doing this will greatly improve the quality of all your draft products.
THERE’S STUFF IN MY BEER – ICK! -- Lines that are not cleaned weekly will develop a build-up of beer stone (calcium oxalate) and protein. This eventually flakes off and ends up in a customer’s glass. Although this debris is not lethal, it will kill sales. There is no substitute for effective line cleaning. The process must include removal and manual cleaning of the faucets and couplers. If lines are neglected for too long, they can become uncleanable and the only resolution is the installation of new lines. You can perform the cleaning yourself, or contract with an outside firm. Either way, it’s a good idea to keep a record of when the lines are cleaned. A Summit draft tech would be happy to demonstrate proper cleaning techniques and answer any questions you may have.
This material was provided by Summit Brewing Company.