Pros and Cons
There are several advantages to kegging. The most obvious is the simplicity of cleaning and filling a keg. A five-gallon batch forces you to handle 50 or more 12-ounce bottles. With a keg you clean and fill one. The keg also takes up less room than 50 bottles and is easier to move.
You can also use your kegging system to force carbonate your beer; that is, carbonate without adding priming sugar to restart fermentation. Force carbonation results in less sediment and a quicker-clearing beer, as well as the option to carbonate and serve the beer within a few hours instead of waiting a week or more for the beer to carbonate on its own.
If you want to precisely control the level of carbonation in your beer, kegging is the only way to go. Force carbonating with a keg and CO2 tank allows you to set the level of carbonation to any level you desire. You can also adjust it, if needed. With bottles you can only set the level of carbonation as precisely as you can measure the priming sugar and the volume of beer you’re carbonating. Even then, you’re at the mercy of how well the yeast can convert the sugar to CO2.
Some people wonder if force-carbonated beer tastes the same as beer that is primed and conditioned. Most of the brewers I’ve talked to think they taste the same. One reason why some beer drinkers may believe they can taste a difference is that almost all beers benefit from aging. The week or two of conditioning that a primed beer goes through allows it to age as well as carbonate. Give a force-carbonated beer the same week or two and it will be almost indistinguishable from its primed cousin.
Another potential reason for kegging is that most filtration systems require a keg system. Likewise, having a kegging system will allow you to use a counter-pressure bottler.
There are some drawbacks to kegging your beer. For one thing, a kegging setup costs more than bottles. You need the keg, a CO2 tank and regulator, fittings, hoses and some sort of dispenser. If you buy all used parts you could put together a system for $70 or so. Buy new and it can go well over $200. Most homebrewers will buy a reconditioned keg and CO2 tank, but new fittings, hoses and regulator; they will end up spending $120–160.
When you keg your beer, you also have to figure out a way to cool the beer. While a bottle or two of beer can be put in the family fridge, a keg cannot. Most people who keg their beer have a dedicated cooler and that’s the best way to go. The alternative is a jockey box, which I’ll explain further on. For now, suffice it to say that cooling a keg is not as easy as cooling a few bottles.
A keg also has places inside where bacteria can hide, so cleaning one is more of a chore than cleaning a bottle. Of course, you only have to clean one. So, for a large number of homebrewers, the benefits of kegging outweigh the drawbacks. Personally, I would never go back to bottling my beer.
The first and most obvious piece of equipment that you need is a keg. Most homebrewers use five-gallon stainless steel kegs that are made for holding the syrup used in soda dispensers. These are commonly called “Corny” kegs, after one of their major manufacturers, the Cornelius Company. Corny kegs are sold by most homebrew stores, but may also be available from local soft-drink distributors. It’s possible to use commercial beer kegs, but cleaning and filling them is much more difficult. In this article, we’ll only consider soda kegs.
Depending on the type, five-gallon soda kegs are 8–9 inches (20–23 cm) in diameter and 25–26 inches (64–66 cm) tall. They usually have protective rubber bumpers around the top and bottom. In the top is an oval opening about 3 x 4 inches (7.6 x 10.2 cm). A lid with a pressure-relief valve fits the opening. On both sides of the opening are fittings containing poppet valves, one for “gas-in” and the other for “liquid-out.” These take quick-disconnects to which you attach hoses. The fittings are often marked “in” and “out.” If not, you can tell which is which by opening the lid and looking inside. The “out” fitting has a long tube (called a dip tube) reaching to the bottom of the keg. Attach your CO2 tank to the “in” fitting and the line to your beer tap to the “out” fitting.
Corny kegs come in two varieties: ball-lock and pin-lock. The difference between them is the type of fittings they have and the kind of disconnects they use. Ball-locks are more common, but check with local homebrew shops to see what’s available in your area. Since they use different connectors, you will have to have duplicate sets of quick-disconnects if you mix keg types. Get at least one “in” and one “out” quick-disconnect once you settle on a keg type. Also, get some food-grade lubricant to use sparingly on the lid gasket and disconnects.
Next you need a CO2 tank. For this you have two options: buy or rent. Welding supply and fire extinguisher businesses are the usual places to get a CO2 tank filled and many will rent you a tank. When you bring it back empty, they take your old one and give you another, filled one. Or you can buy a tank of your own. These are available either new or reconditioned, in steel or aluminum.
Find a place to fill the tank and see what its policies are. Some places won’t handle aluminum tanks. Others will only exchange tanks — they won’t fill your tank and give it back to you. This may determine whether you buy or rent and what kind of tank you get. I have a 5 lb. (2.3 kg) tank and it usually lasts through four to five batches of homebrew. The most common tank sizes are 5, 10 or 20 lbs. (2.3, 4.6 or 9.1 kg). Larger tanks obviously last longer, but they’re bigger and heavier.
You will need a regulator for the CO2 tank. You can buy either single-gauge or double-gauge regulators. Single-gauge regulators have one gauge showing the pressure being applied to the keg, with an adjustment knob to set that pressure. Double-gauge regulators have an additional gauge showing the pressure remaining in the tank. This tells you when the tank is almost empty, but it won’t tell you, for instance, when you’ve used half of the tank.
The tank gauge only registers a drop in pressure towards the end of the fill because CO2 is not sold as a gas. Your tank is filled with liquid CO2 under about 800 psi (41,000 Torr) of pressure. As you use CO2, the liquid boils off and turns into a gas as it comes out of the tank. As a result, the pressure in the tank stays close to 800 psi (41,000 Torr) until all of the liquid is gone. From then on the pressure drops as you use up the remaining gas.
Your regulator should come with a check valve to prevent beer from being forced back into the regulator’s mechanism.
Next you need equipment for dispensing the beer. Here again you have two basic choices: a picnic tap or a faucet. A picnic tap (also called a cobra tap) attaches to the end of a hose and is held in your hand. You squeeze the handle to dispense the beer. A faucet is the kind of tap you see at your local pub. Mounted solidly in some way, you pull on the handle to open the faucet and dispense the beer. Picnic taps are cheaper and easier to set up, but I prefer the look and feel of a mounted faucet. Having a picnic tap as a backup is a good idea if you ever want to take a keg with you to a party.
You also need hoses to connect the CO2 tank to the keg and the keg to the tap or faucet. Either 1/4-inch (0.64 cm) or 5/16-inch (0.79 cm) inside diameter hose can be used from the regulator to the gas-in disconnect. The tubing used for gas should be rated to withstand at least 50 psi (2590 Torr). Small hose clamps should be used to secure the hose to the fittings.
For the hose going from the beer-out disconnect to the tap, I recommend 3/16 inch (0.48 cm) inside-diameter, food-grade tubing. In this case the pressures will be low, so the psi rating doesn’t matter.
Finally, you need a way to cool the beer. As mentioned before, the options are a refrigerator that fits the keg, or a jockey box. (See the Sepember 2002 column, “The DraftErator,” for instructions on how to build a dedicated keg cooler.) A jockey box is a cooler that contains a coil of copper or stainless steel tubing. The keg is connected so that the beer flows through the tubing before being dispensed. The cooler is filled with ice until it covers the tubing, so that the beer is quickly cooled as it flows through to the glass.
Similar alternatives include a cooling coil inside a refrigerator, or a “cold plate.” A cold plate is a block of aluminum that has tubing running inside it. This is set in ice or a refrigerator and the beer is run through it the same as with a jockey box. (See the December 2002 Projects column, “Tap-A-Fridge,” for an example of a refrigerated jockey box.)
If you use a refrigerator, you can dispense via a picnic tap that stays inside with the keg or you can run a faucet through the door or sidewall of the fridge. If you run a faucet through the fridge, be careful when drilling not to damage the cooling coils that are inside the walls.
My favorite arrangement is a chest freezer with a temperature controller. The controller maintains the chest at a temperature above freezing. You set the thermostat on the freezer as low as it will go and plug the freezer into the controller. The controller turns the freezer on and off to maintain the temperature you desire. These are available at most homebrew shops for about $50.
My own setup is a chest freezer with a collar made of 2x6 lumber that fits between the top of the chest and the lid. The CO2 is fed into the kegs via a hose running through the collar. A manifold on the inside routes gas to as many as three kegs. Beer faucets are mounted on the front of the collar for dispensing. All the holes are drilled in the collar, none in the freezer, so I can easily restore the freezer to its original condition.
Should the CO2 tank be inside or outside the refrigerator? Either way works. The only problem with putting the tank inside is that some people get condensation within their regulator gauges as a result. For that reason I recommend outside, but only if it’s convenient.
Mini Kegs: What to buy for less than a batch
While kegs are nice, it’s hard to grab a five-gallon keg and go to the beach. A more portable “package” is often desired. Additionally, being able to fit your beer in your refrigerator and still have room for pizza is useful. For homebrewers, there are several smaller packaging options.
The Party Pig ($40) is a 2.2-gallon (8.5 L) PET bottle with a dispensing tap. It does not use CO2 cylinders. It has a “pressure pouch” that inflates by a chemical reaction and expels the beer. Some users have difficulty getting the pressure pouch to activate, but with practice, it’s not hard. The cost of the bag is $4 and it has to be replaced each brew. Because there is no easy way to exchange a lid for the tap, you must have a dispensing tap for every bottle you have in storage. One must carbonate by bottle conditioning or fill from a keg.
Tap-A-Draft is the newest package to enter the homebrewing market. It uses a six-liter (1.6-gallon) PET bottle. It can also use three-liter (0.8-gallon) PET soda bottles. Some suppliers include the tap with bottles and extra lids, and some sell it all separately. To push out the beer, it uses disposable eight-gram CO2 cartridges that cost 50 cents each. Two cartridges are needed to dispense one six-liter bottle. The pick-up tube is a small vinyl hose that also provides the restriction needed to pour without foam. The Tap-A-Draft is very well-engineered and affordable. It takes a little more than three six-liter bottles to hold one 5-gallon brew. One can carbonate either by priming or by forcing CO2, which requires two extra cartridges. Since the valve is a “thread-on” you only need one valve for an unlimited number of bottles. You simply replace the bottle lid with the valve when you are ready to dispense. Bottles cost $7. The dispenser costs about $35. You will only need one valve for each flavor you want to pour, no matter how many bottles you have. With the Pig, there is no way to bottle a five-gallon batch without owning two complete kits.
The Mini-Keg system is comprised of small plastic-lined metal kegs. Many manufacturers make taps for the Mini-Keg. Its capacity is 5 liters (1.3 gallons) and it has been in use for some time by the breweries in Europe. Prices start at $65 for four kegs and a hand pump. The kegs are lined steel containers and have a short life. Once the liner is damaged the keg will rust and needs to be discarded. When they need to be replaced they cost $8. Longevity depends on care. The tapping systems use air or CO2. CO2 taps are available starting at $80 with four kegs. There is a replaceable rubber bung that costs $1. CO2 cartridges are either the 8-gram (50 cents) or the 16-gram ($1.25). Only one valve is required for an unlimited number of kegs.
Beer Party 2 fits any screw-on-top bottle. This dispenser is similar to the Tap-A-Draft, except it is made of metal. It comes with adapters for any large-bottle thread. It’s usually used with two-liter (0.5 gallon), three-liter (0.8 gallon) and six-liter (1.8 gallon) bottles. It is extremely difficult to find unless you bought one in Japan while they were made. This dispenser is of the highest quality. If you are lucky enough to find one, give it a try. Pricing is unavailable but would likely be in the range of $100 for the tap alone.
Keggy is a 5-liter (1.3 gallons) or 12.5-liter (3.3 gallons) package made in Germany. This is the coolest package I have ever seen! It is a stainless keg, refillable CO2 bottle and dispenser in one unit. The cost is extremely high and it is rarely used in homebrewing. It would be better suited to a small brewery with lots of money.
10-liter (2.6 gallon) Sanke kegs are available as well. This vessel uses a standard tap for any Sanke keg, but it is small enough to fit in a refrigerator, as long as you are a bachelor. They run $60 used and $150 new and will last a lifetime. Tapping systems are around $150 unless you scrounge the parts.
All of these solutions are well-proven by homebrewers and, while they are more expensive than bottling, I trust you will find them an improvement for most applications.
Cleaning and Filling
New kegs should be disassembled and cleaned before use. Start by opening the lid and checking the large gasket around it. If it was last used for soda syrup, it will hold the smell and you’ll have to replace it as well as the gaskets in the fittings.
The fittings screw off. With pin-lock kegs, you have to buy a special socket or make one yourself by notching a socket with a grinder. Once you remove the fittings you can pull out the tubes held underneath them.
If the keg isn’t too dirty, soap and water will clean it. If that doesn’t work, try B-Brite or PBW. Chlorine can break down the outer layer of stainless steel, allowing corrosion to get a foothold, so sanitize your kegs with something like iodophor or Star-San.
The kegs don’t have to be disassembled every time you clean them. Most of the time I just swish mine with hot soapy water, then run some through the beer-out fitting. I follow that with a hot water rinse and some iodophor solution, running a bit of each through the beer-out fitting. I only disassemble them every fourth or fifth time I use them.
When you’re ready to fill your keg, start by putting CO2 into it. This will prevent oxidation of your beer during transfer. Release the pressure, take the lid off and rack your beer into the keg under the “blanket” of CO2. Now “purge” the keg. This is the process of removing air from the headspace (the space inside the keg above the liquid) and replacing it with CO2. You can do this by pressurizing the keg with CO2 and letting it sit for a couple of minutes. The CO2 is heavier than air andwill settle to the bottom. You can let the air out through the relief valve on top of the keg or by pressing on the gas-in poppet valve. Repeat this step two or three times to get out all of the air.
I’ve been asked if kegged beer can be stored as long as bottled beer. The answer is yes, as long as you are careful. For beers that are going to be stored for long periods, disassemble the keg, carefully clean and sanitize each piece, and purge thoroughly after filling.
The ability to precisely control carbonation is a big advantage of kegging. It requires, however, an understanding of how carbonation is measured and set. The carbonation level of beer is measured in “volumes” of CO2. This is calculated by dividing the volume of CO2 dissolved in the beer by the volume of beer in which it is dissolved. So, if you had one liter of CO2 at ambient pressure and you dissolved all of it into one liter of beer, the beer would contain one volume of CO2. Two liters of CO2 dissolved into one liter of beer would make two volumes of CO2.
Figure 1 (at right, above) shows some typical carbonation levels for different types of beer.
Controlling your beer’s carbonation level introduces the concept of “equilibrium pressure.” When you fill your keg with beer, then put CO2 under pressure on top of it, it will begin to absorb the CO2. The colder the beer, the more CO2 it will absorb. Also, the more pressure you apply, the more CO2 it will absorb. The equilibrium pressure is the pressure at which the rate of gas diffusing into the beer equals the rate of gas diffusing out of your beer (into the headspace). At equilibrium pressure, your beer will absorb a specific volume of CO2.
One way to visualize this is to think of a plastic soda bottle. Before you open it, it is highly pressurized and if you squeeze it, it feels very hard. Open it up and you release the pressure. Pour a glass and you create headspace in the bottle. Put the cap back on, give the plastic bottle a squeeze and it will be quite soft.
Wait a few minutes, though, and it will get harder. That’s because the CO2 in the soda is coming out of solution, filling the headspace and creating more pressure in the bottle. The CO2 will continue coming out of solution, slowly increasing the pressure in the headspace and reducing the volume of CO2 in the soda, until the pressure of the CO2 in the liquid equals the pressure of the CO2 in the headspace; this is the equilibrium pressure.
Figure 2 (see page 42) shows the equilibrium pressure for different temperatures and volumes of gas in beer. Find the serving temperature on the right and the volumes of CO2 you desire on the top; where they meet in the table shows the equilibrium pressure. So, for instance, if your beer is cooled to 45 °F (7.2 °C), and you want it to contain 2.1 volumes of CO2, you would pressurize it to 10.2 psi (530 Torr) — the equilibrium pressure for that combination — and let it sit with the tank connected to the keg until as much CO2 as possible had dissolved into the beer; this process will take a week or so.
The equilibrium pressure can also be determined mathematically. Figure 3 (above) shows a formula that can be put into a spreadsheet. Fill in the temperature and volumes of CO2 and it will calculate the equilibrium pressure.
Kegs give you the option of serving your beer much quicker, though. Cool the beer first, turn the pressure up to 20 psi (1040 Torr) or higher and shake the keg to make the CO2 dissolve quickly. When the CO2 stops hissing out of the tank, let the keg settle for an hour or so and drink! The drawbacks to this method are that you lose the benefits of aging and you won’t know how many volumes of CO2 are initially dissolved in your beer.
The final method for carbonating beer in kegs is to prime and condition. Priming in kegs is essentially the same as priming bottles; you just treat the keg like one big bottle. The difference is that you use proportionally less priming sugar; 1/3-1/2 cup for a five-gallon (19 L) batch is all you need; any more and you’ll get excessive foaming. The drawback to this method is that you end up with yeast sediment in the bottom of the keg. This sediment will mostly be drawn out with the first glass or two that you pour. After you start pouring, connect your CO2 tank to maintain the level of carbonation and push out the rest of the beer.
Of course, regardless of how you carbonate your beer in the first place, you can adjust the carbonation any time. Too fizzy? Reduce the pressure at the regulator, relieve the pressure in the keg and give it a few days. Not fizzy enough? Set the pressure higher and wait. Keep adjusting until your beer has precisely the carbonation level that you want.
Dispensing is what it’s all about. Pulling on the tap handle of your keg and pouring a precisely carbonated beer, with just the right amount of head, is why you bought all that equipment in the first place.
Now you need to decide how to dispense your beer. A picnic tap and jockey box is probably the simplest way. Most brewers want a fridge to keep their beer in, though, and with a fridge — or freezer with temperature controller — you might as well mount a faucet.
The objective is to dispense your beer with enough foam to give it a nice head, but not too much foam. The dip tube in the keg, the fittings, the hose and the tap — everything between the beer and your glass — will restrict the flow of beer out of the keg. Most of the restriction comes from the hose that runs between the keg and the tap. Happily, this is the easiest thing to control. When pouring, the amount of restriction needs to match the pressure in the keg. Too little restriction and the beer will flow too quickly and foam heavily. Too much restriction and the beer will barely trickle from the tap, as well as foaming more than it would with just the right amount.
Some brewers adjust the pressure from their CO2 tank down for dispensing, then back up to the equilibrium pressure for storage. An easier way is to “balance” the system; that is, run the right length and size of hose between the keg and the tap so that the restriction matches the equilibrium pressure. Then you don’t have to make adjustments while serving.
A 3/16-inch (0.48 cm) inside diameter hose provides about 3 psi (160 Torr) of restriction for every foot (30 cm) in length. A 1/4-inch (0.64 cm) inside diameter hose provides about 1 psi (50 Torr) of restriction per foot (30 cm). So, if you have 3 feet (91 cm) of 3/16-inch (0.48 cm) hose between your keg and your tap, it will provide 9 psi (470 Torr) of restriction. This is just right if you have the regulator on your CO2 tank set to 9 or 10 psi (470 or 520 Torr).
If you use a jockey box, you’ll need more pressure on the keg to push the beer through all that tubing and you’ll want to use larger tubing. In that case, experiment with the CO2 pressure to see what works. I would start with 15 psi (780 Torr) and work up or down (probably up) from there.
As an example, my “house” beer is an American pale ale that I serve at 42 °F (5.5 °C) and carbonate to about 2.2 volumes of CO2. The equilibrium pressure for that combination is 10 psi (520 Torr), so that’s where I set my CO2 regulator. Knowing this, I put a little over three feet (91 cm) of 3/16-inch (0.48 cm) hose between my kegs and my beer faucets. This way I carbonate and serve my beers at the same pressure and rarely have to change it. If you have a long run between your kegs and your faucet, use larger diameter hose.
In any case, start with a longer hose than you think you’ll need. It’s easier to shorten the hose to make adjustments than it is to replace the hose with a longer one.
Putting together a draft system takes time, effort and money. The first time you pull a perfect pint from your own tap, though, you’ll know it’s worth it. And speaking of pulling a perfect pint, I believe I hear one of my own kegs calling to me!