How To Keg

Set up a Simple Home Draft System by Kirk R. Fleming;  John Palmer, Brewing Techniques' Jan/Feb 1997 issue.  
     Sooner or later you'll meet a brewer who shares with you the joy of home-brewed draft beer.  Drawing a glass of fresh ale or well-aged lager from the keg has an appeal that somehow goes beyond mere words.  After you've seen for yourself how much fun (and how cool) draft-at-home can be, you'll probably be on your way to the store to get set up.  In fact, you may have just received a draft system are wondering how to use it.
    Understanding the benefits, costs, and special considerations involved in kegging will help you make better choices when it comes time to set yours up. This column describes what you'll be getting into, and what you'll get out of the whole experience.
     First off, kegging is all about convenience and control. Convenience, because you can forget about cleaning and sanitizing bottles, storing empties, and waiting weeks for beer to condition in the bottle. Control, because you'll be able to easily adjust carbonation levels to your liking for a given style or batch. A home draft system also opens the door to other possibilities, like closed beer transfer and filtering for crystal clear beer. 
     Of course, all these benefits have some cost, depending on the type of draft setup you choose. The cost of the basic Basic Home Brew Draft Kits  itself can be relatively high (though it will pay for itself many times over in convenience).
 single tap
     Storage and refrigeration of kegs is another concern. Kegs come in a variety of sizes, including convenient 5-L mini kegs. While the smaller kegs fit neatly into any refrigerator, larger kegs are a bit bulky and place demands on storage locations, transportation, and cooling needs. A dedicated beer storage refrigerator is almost a requirement, and it takes a fairly sizable fridge to store more than a couple of kegs. Other options are available for getting cold beer from a keg (jockey boxes, for example), and many brewers get by just fine without dedicated refrigerators.
Hardware You'll Need
     By far the most common system used by home brewers for draft beer is the 5-gallon soda canister, originally manufactured by the Cornelius Company (Annoka, Minnesota). Though other companies also make similar models (notably the Firestone brand [Spartanburg Steel Products, Spartanburg, South Carolina], whose kegs are virtually identical to Cornelius's -- though parts are not necessarily interchangeable), the style is usually referred to as a Cornelius or "Corny" keg. These stainless steel canisters were developed and used to distribute premixed soda for common restaurant dispensers. The keg shape, capacity, and fittings are standardized, and over the years millions have been manufactured. It takes only a small conceptual leap to see they can dispense beer the same way they once dispensed diet cola.
     The complete keg draft-beer system is very simple. A typical system includes a Corny keg to hold the beverage, a CO2 (carbon dioxide) gas tank to pressurize the keg (for force-carbonation and dispensing), a gas regulator to lower the gas-tank pressure to a usable level, a hose with a quick-disconnect fitting to connect the CO2 tank to the Corny keg, and a hose with a plastic faucet or "picnic tap" and quick-disconnect fitting to dispense the beverage.
     The keg: Most kegs are 8-1/2 in. in diameter, about 26 in. tall, and hold 5 gallons of liquid. The top and bottom ends of the kegs are covered with shock-absorbing plastic caps. The cap on the top end of the keg is molded to provide handles for easy lifting, although older kegs made by the Cornelius Company had no end caps at all but relied on a single metal handle bolted to the top. Kegs may or may not have a pressure-relief valve in the lid -- an important safety feature.
soda keg
Kegs are available with two types of valves, ball-lock and pin-lock, which refer to the method used to couple the hose fittings to the valves. The fittings are threaded slightly differently and are not interchangeable, so it's a good idea to pick one keg type and stick with it to avoid confusion. Ball-locks are a bit easier to disassemble with your average socket set. Plan to buy at least two kegs so you won't have to finish one batch before kegging another.
     CO2 tank: You'll also need a high-pressure CO2 tank to provide gas for carbonation and dispensing the beer. All tanks should be stamped near the top with a pressure test or certification date, and must be recertified every five years. If you can't find a date stamp, ask the person selling the tank to show it to you. No responsible dealer will fill a tank with an expired certification. Recertification, if needed, will cost you extra. 
     Pressure regulator: You'll also need a single or dual-gauge gas pressure regulator for the tank, which is used to drop the gas pressure from the 800 phi or so in the tank to the 10-30 psi you'll need for force carbonation and dispensing The regulator is adjustable so you can set the output pressure to control carbonation levels and to control how the beer serves. Regulators include a pressure relief valve that will blow at or below the maximum pressure indicated on the low pressure gauge.
     One or two gauges? Both single and dual-gauge styles work perfectly well. Both include a gauge that indicates the output (low) pressure setting, which is the most important information you need.
     The dual-gauge unit also includes a second gauge that indicates the tank pressure, which tells you roughly how much gas is left. Knowing the tank pressure, though, is only marginally useful; it drops from 400 to 0 psi in what often seems to be the last few minutes of use. When the gauge says "almost empty," for all practical purposes, it's empty.
     Connections: To connect the gas tank to your keg and to dispense the beer, you'll need two quick disconnects, a gas line, and a beverage line with a picnic faucet.
disconnects                 picnic tap
     Disconnect fittings are available in both ball-lock and pin-lock styles to match the keg type.
     To gain the most from your investment, use the flare-style outlet -- it's a short metal insert with a male thread. This style of fitting allows you to connect either pin-lock or ball-lock fittings to your regulator and even connect several kegs at the same time. 
Getting Your Beer into the Keg
     If you know how to fill a bottle, then you can fill a keg. The process is basically the same, and sanitization is every bit as important.
     Cleaning: Most of the component parts of Corny kegs will contact the beer, so it is extremely important that all parts -- especially in used kegs -- be properly cleaned and sanitized before use. For details on  how to disassemble and clean Corny kegs, see the box, "The Care and Feeding of a Cornelius-Style Keg." After cleaning your keg, leave it inverted in a clean container while you prepare for racking.
     Priming: It is possible to prime your beer just as you would normally do for bottle-conditioning. You could then use a hand pump and picnic tap to dispense the beer. A CO2 system, however, makes it easier to obtain a consistent level of carbonation, and the carbonation can be adjusted at will.
     Racking and purging: Some brewers prefer to purge the Corny keg with CO2 before racking to avoid any possibility of oxidizing the beer; others simply rack into the keg as they normally would any carboy. If you choose not to purge the keg, make sure your racking tube is long enough to reach to the bottom of the Corny keg when you begin. Ideally, it should be long enough to remain below the surface of the beer during the entire process to prevent aeration and premature staling of your finished beer.
     After racking is complete, fit the sanitized keg lid into the top of the Corny keg and seal it with the retaining bail. Whether or not you purge before racking, it is important to purge the headspace with CO2 before pressurizing. If your keg has a pressure-relief valve, open the valve by pulling on the valve ring and turning the ring 90deg to lock the valve open. To purge the keg, set the tank regulator to about 30 psi and connect the gas to the IN side of the keg. Let the gas flow into the keg for about 30 seconds or so, then close the relief valve. If your keg doesn't have a relief valve in the lid, an alternative purging technique is to leave the lid unsealed to allow the keg to vent. You will need to reduce the purge pressure to about 5 psi to reduce splashing. Once the headspace has been purged (it should only take a minute or two), seal the lid. You're now ready to carbonate.
Force Carbonation
     Background: Your beer's carbonation level, known as "the condition in the beer," is determined by both the temperature and the pressure of the beverage.
     Most gases are more soluble in cold liquids than in warm, and higher pressures keep that gas from escaping into the atmosphere. The amount of gas dissolved in beer (its carbonation level) is measured in volumes. To say the carbonation level is "2 volumes" means that every cubic inch of beer has 2 cubic inches (at standard temperature and pressure) of CO2 dissolved into it.
     As with all other aspects of beer, tradition and personal taste determine how much the beer is conditioned. Un pressurized finished beer has between 1.2 and 1.7 volumes of CO2 per volume of beer. Most beer is packaged with 2.3-2.8 volumes of CO2 (compare this to sodas, which contain 3.5 volumes). Each beer style, however, has a traditional carbonation level, just as it has a traditional hop bitterness. Belgian ales and German Weiss, for example, are usually carbonated to 3-3.2 volumes but are sometimes found with as much as 5.1 volumes. In the case of cask-conditioned real ale, the desired level has to do with physics. At typical cellar temperatures (50-55 degrees F [10-13 degrees C]) and ambient pressure, an open cask of ale can hold only about l volume of CO2. That defines "true-to-style" carbonation for a British real ale.
     For ale served at about 50 degrees F (10 degrees C), a good starting point is to carbonate the beer for several hours, maintaining 10 psi. The 3/16-in. diameter vinyl beer line tubing drops about 3 lb of pressure per foot of length, with an additional half pound pressure drop for every vertical foot that the keg is above the source. If you're dispensing with a 3-ft., 3/16-in. ID. dispense hose and picnic tap, a 10 psi pressure should give you a very nice serve. At pressures of 15 psi and above, you'll probably see a little excess foam.
     Now you're ready to carbonate the beer: With the tank set at the pressure required for the desired carbonation level, allow the keg to pressurize until you no longer hear any gas flow, then agitate the keg by rocking it gently (on its side, for best results). This agitation exposes more surface area of the beer to the CO2 and allows the gas to dissolve faster.
     If you can refrigerate the keg with the gas supply attached, then simply leave the regulator set to the desired pressure and agitate occasionally. When the beer is at serving temperature and no more gas flows into the keg when you agitate it, the beer is conditioned. The time needed to get perfectly conditioned beer depends only on how quickly you can cool the beer to serving temperature and how much time you spend agitating it to dissolve the CO2.
     If you can't refrigerate the keg while connected to the CO2 tank setup, you'll have to repeatedly connect the gas, agitate the keg, disconnect, and continue cooling. With the regulator set to the desired final keg pressure, each charge of gas is fairly small. To speed the process, you can over pressurize on the first few charges. This puts more gas into the keg. On each successive charge, reduce the regulator pressure downward toward the desired final pressure. With practice, you can gauge this process so that on the last attempt to add gas at the final pressure and temperature only a small amount of gas flows into the keg and conditioning is complete. Regardless of the technique you use, fully conditioned beer can be yours in a matter of days. 
     Dispense: Whether or not you force-carbonate your beer, you will find yeast sediment at the bottom of your keg. Cutting 3/4-in. from the end of the long dip tube will prevent sediment pick-up during dispense. 
     A cold draft: Instead of using a simple picnic tap to dispense their beer, many brewers choose to install a beer faucet right in the fridge.
     Accessories: With the convenience of CO2 pressure, an entire world of opportunity opens up to the inventive home brewer. CO2 can be used to pump beer anywhere you want. You can easily set up a closed transfer system for moving beer from one keg to another by using quick-disconnects with threaded fitting outlets and lengths of tubing terminated with female swivel fittings. 
     A draft system also makes filtering easier. Replaceable cartridge filters can be installed in the transfer line to provide crystal clear beer in the dispense keg (see Jim Busch's column on filtering [1]). Other optional equipment includes counter pressure bottle fillers (2), insulation jackets, and adjustable pressure relief valves (3). Corny keg fittings and repair parts are available almost everywhere soda is sold. The 5-gallon soda canisters offer an endless variety of other uses. 
     If you choose to modify your keg, limiting your experiments to the keg lid will ensure that mistakes can be easily fixed without destroying the keg itself.
     Kegs that are just too ugly to use for beer, or are missing valve parts and aren't worth reconditioning, make excellent storage containers for grain and hops. And don't overlook the container's original purpose; many homebrew supply shops also sell soda-making kits. You may find that making your own root beer or ginger ale is a lot of fun, or you may just like having a few gallons of soda water on hand to quench a summer thirst.
Control Outweighs Cost
     For about $200 you can easily relieve yourself of the tedium of priming and bottling and enjoy the convenience and flexibility of a complete kegging setup. Once you've tried it, I'm sure you'll never want to go back. If you've often thought you'd like to have complete control over your beer's carbonation level, or you'd like to filter it more easily or ferment under pressure to naturally carbonate, kegging is probably your answer.
     Some brewers like to use kegs as fermenters. Although some published articles have commented on the less-than-optimal shape of the keg for fermenting (too tall and narrow), it is an option that has worked well for many.
     Primary fermentation: About the easiest way to temporarily set up a keg as a primary fermentation vessel is to simply remove the entire gas IN valve assembly and tube. Slip a length of 1/2-in. ID. vinyl tubing over the threaded fitting and run it into an airlock. 
     If you brew beers that typically have enormous amounts of blow-off, you can modify a keg lid for dedicated use as a fermenter by drilling a hole big enough for a blow-off hose. Enlarge it if needed using a hand grinder or a file. Fittings, washers, and seals available at your local hardware store will enable you to use a blow-off tube that's larger than 1/2 in. 
     Secondary fermentation: To avoid these modifications and the cleanup associated with primary fermentation in Corny kegs, you can use them only for secondary fermentation. After completing the primary in an open fermenter, I rack to an unmodified, sanitized Corny. Every other day or so I relieve gas pressure that builds up inside the keg by simply pressing the gas-side valve or the pressure relief valve open for a second or two. 
     Fermenting under pressure: For those who want to ferment under pressure to naturally carbonate their beer, constant-pressure relief valves can be purchased for both ball-lock and pin-lock kegs. Lager brewers in particular will find it useful to control and maintain the pressure in the keg as the temperature drops slowly and the pressure increases. Typical adjustable relief valves are spring-loaded and can be set to relieve pressures between 5 and 30 psi. They attach to the keg's quick-disconnect fitting.
     After the secondary fermentation is complete (or if I'm laagering), I prefer to rack a third time to a sanitized Corny keg. This final keg is placed in the fridge for force carbonation, cold conditioning, and draft dispense. Every time the beer is racked from one container to another, however, the chance of aeration and infection increases, and you may be uncomfortable using this technique. With careful handling, however, you won't experience any problems. 
     An alternative is to leave the beer in the primary a little longer than normal before racking it to the secondary. The longer settling time will generally result in less sediment by the end of secondary fermentation. The secondary fermenter then also serves as the dispense tank, with the addition of a modified dip tube (the tube that's in the OUT side of the keg). 
     A popular recommendation for this application is to cut off the bottom 3/4-1 in. of the long dip tube using a tubing cutter or a hack saw. After filing the end to remove burrs, reinstall the tube in the keg. The shortened tube will prevent the pickup of sediment during dispensing of moderately to strongly flocculant yeast strains. 
     Another approach that works well is simply to add gelatin or isinglass finings to the beer on final racking from the secondary to the final tank and before cold storage. When well mixed, the finings will drop any remaining yeast to the bottom of the keg, and even unmodified dip tubes won't pick up the sediment