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The Care and Feeding of a Cornelius-Style Keg

Not Just for Dispensing
Ferment, Lager, and Clarify with Cornelius-Style Kegs

CO₂ Temperature Pressure Guidelines for Carbonation

by Kirk R. Fleming;
John Palmer, column editor
Republished from BrewingTechniques' January/February 1997 issue.

The benefits of convenience and control far outweigh the cost of setting up a home draft system. This article shows how easy it can be to keg at home.

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 during the holidays and 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 equipment itself can be relatively high (though it will pay for itself many times over in convenience).

Storage and refrigeration of kegs is another concern. Kegs come in a variety of sizes, including convenient 5-L minikegs. 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. Nowadays, soda producers are replacing the kegs with disposable poly bags in cardboard boxes. The old kegs can be purchased from soda distributors and reconditioned for a higher purpose. It takes only a small conceptual leap to see they can dispense beer the same way they once dispensed diet cola.

Costs for a Typical Kegging System
	New	Used
5-gal Cornelius keg	$100	$30
CO2 tank, 5-lb, aluminum	$80	$40
Pressure regulator, dual-gauge	$50	$50*
Hoses with quick-disconnect fitting	$10	$10**
Hose with picnic tap	$15	$15**
Total kegging system	$255	$145
Note: Steel CO2 canisters can be cheaper than aluminum, and used steel canisters will save you still more. Many homebrew supply stores sell kegging packages that come with or without the keg/canister. * I've never seen used gauges. ** Used hoses are not recommended.

This article focuses on Cornelius-type kegs because they are the most commonly used kegs in home brewing, and also because they require some instruction. A variety of other home draft systems are available on the market, complete with documentation and home brewer-friendly features. For these, inquire at your local homebrew supply store or consult the companies advertised in this magazine.

The complete Corny 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 Corny 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. Prices vary, of course, but generally such a system costs about $200 (see box, "Costs for a Typical Kegging System").

The Corny keg: Most Corny kegs are 8-1/2 in. in diameter, about 26 in. tall, and hold 5 gallons of liquid. Somewhat shorter, 3-gallon kegs are available, and a larger diameter 10-gallon variety can occasionally be found. 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.

Corny 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. Relative availability varies by region.

Used 5-gallon kegs cost about $30 each, and the 3- and 10-gallon sizes cost about $10-20 more. You can also purchase new kegs, but they run nearly $100 each. Plan to buy at least two kegs so you won't have to finish one batch before kegging another.

Used aluminum tanks -- often in 2.5-, 5-, and 10-lb sizes -- are also available and are sold new by many mail-order houses. Prices for new tanks vary considerably; aluminum is usually more expensive than steel, $80-$100 for the 5- and 10-lb sizes, but their smaller sizes are much more convenient. Unless portability is a big consideration, go for at least the 5-lb tanks. Better yet, just buy a 10-lb tank. The folks who fill the tanks charge a flat labor fee regardless of size, so keep in mind that smaller tanks may cost anywhere from two to four times as much to fill per pound of gas.

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 psi 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 -- around 50-60 psi for most regulators.

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. But because dual-gauge regulators cost within a few dollars of single-gauge models (about $40 for single, and about $50 for dual), it's probably worth it to get at least some warning. Nothing is worse than running out of CO₂ at 7 p.m. on a Saturday night with thirsty friends in line at the cooler.

Connections: To connect the gas tank to your keg and to dispense the beer, you'll need two quick disconnects (about $5 each), a gas line, and a beverage line with a picnic faucet (about $15 each with swivel fittings).

Disconnect fittings are available in both ball-lock and pin-lock styles to match the keg type. In addition to the lock type, the fittings are also available with either hose barb or flare outlets.

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. In fact, acquiring an assortment of vinyl hoses fitted with the matching swivel-flare nut fitting gives you lots of options beyond simple packaging and dispense..

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. Nonpressurized 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 degF [10-13 degC]) 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.

Table I shows the pressures that are needed at various temperatures to obtain a given level of carbonation. Choose the desired serving temperature (the temperature at which you'll keep your keg) and the desired carbonation level (in volumes). The chart will indicate the conditioning pressure needed. After your keg of beer has had a day or so to condition at the selected pressure, you may need to reduce the pressure for serving (usually to about 10-15 psi). The carbonation level will eventually drop to this lower setting, but the process is very slow. You'll probably find that, once carbonated, the beer can be kept at dispensing pressure until consumed.

For ale served at about 50 degF (10 degC), 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. i.d. 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 overpressurize 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.

Jockey Boxing Your Beer

One of the challenges of kegging your beer is chilling it for dispensing if you don't have a refrigerator to store it in (once chilled, it will stay cold for hours). The jockey box is one handy solution that allows portability and flexibility in how and where you dispense your homebrew. A jockey box is essentially a coil or plate cooler set up in an ice chest. You may have seen them at outdoor tastings or beer festivals -- standard beer faucets mounted through the front of a picnic cooler. Inside the chest, one end of a stainless steel coil mounts to the back of the faucet, and the other end of the coil exits through the back side of the cooler and connects to the keg. The coil inside is surrounded by ice. When the faucet is opened, beer under pressure from the keg is pushed through the coil and chilled before it pours out the tap. Jockey boxes eliminate the need to keep the entire keg cold (although you'll always want to keep your beer at least cool). To get cold draft beer, you need only fill the cooler with ice.

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 counterpressure 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. (For an example of practical keg modification, see Dion Hollenbeck's article on modifying kegs for use with aeration stones [4]).

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.

References

1. Jim Busch, "When Beer Must Be Clear -- Techniques and Technologies for Clarifying Homebrew," BrewingTechniques 4 (1), pp. 24-29 January/February 1996).

2. Bennett Dawson, "The Poor Man's Counter-Pressure Bottle Filler," Brewing Techniques 4 (1), pp. 30 (January/February 1996).

3. Steve Stevens, "Basic Minikeg Modification for Improved Pressure Regulation" BrewingTechniques 4 (3), pp. 32 (May/June 1996).

4. Dion Hollenbeck, "How to Modify a Soda Keg Lid for Best Use with Aeration Stones," BrewingTechniques 3 (5), pp. 32-37 (September/October 1995)..

Further Reading:
For other articles on kegging, see the article index at http://www.brewingtechniques.com/library/articleindex.html