| 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. |
| 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 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. |
| 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. |
| 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.
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. |
| 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. |
| 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. |
