An Introduction
to the
Cornelius Keg System


The Cornelius keg system is simply the CO2 system of choice for great majority of home brewers who keg their own beer. The Cornelius kegs are the canisters in which soft drink syrups are delivered to vendors by soft drink bottlers such as Coke and Pepsi.

The availability of these soft drink canisters to home brewers has been due to the major bottling companies converting their distribution networks from the Cornelius system to the "bag-in-the-box" system. Their availability will vary in some parts of the country.

The benefits of this system are manifold. Being stainless steel, it keeps your beer well protected. It is very easy to clean between batches. There will be only one (1) keg to clean instead of 50 bottles. Carbonation can be easily controlled even though it is generally lower than bottled beer.

The Equipment

The equipment in the Cornelius keg system consist of a canister, a beverage set-up, a gas set-up, a CO2 regulator and a CO2 tank.

The Canisters

The canister is made of stainless steel and comes with a lever-lock lid which requires the use of an O-ring which insures a air-tight seal if attached properly. The opening for the lid is of adequate size to allow access for the purpose of cleaning the canister. The canister is fitted with two (2) plugs (sometimes referred as adapters); an "in" for the gas and an "out" for the beverage, which allows for easy attachment of the disconnects. The plugs also determine the type of canister; pin-lock or ball-lock.

The pin-lock canisters are used by the Coca-Cola Bottling Company, while the ball-lock canisters are generally used by the Pepsi-Cola Bottling Company.

To distinguish pin-lock from ball-lock, examine the plugs. On the gas or inlet plug, two (2) pins extending horizontally on opposite sides of the plug while there will be three (3) equally spaced pins extending from the beverage or outlet plug. The ball-lock canisters will not have pins present on either plug.

Some canisters are available in three (3), four (4), five (5) and even ten (10) gallon capacities, with the five (5) gallon size being the most readily available.

When buying a canister, you can buy a shinny “new” one for $95-110, a reconditioned used canister for $40-50, or a used one for $10-30. The new canister will eventually look somewhat like the reconditioned used one does so why spend the money. Stainless steel will not rust unless the wrong type of cleansing agents are used so lets discuss how to save some money. A reconditioned canister, will mean that all three O-rings associated with the kegs have been replaced - the O-rings for the lid, for the plug and for the pick-up stem. In most cases, reconditioned also indicates the canister has been cleaned inside and out to give it a shiny appearance.

At this time, ball-lock canisters are becoming more and more difficult to locate. This situation would therefore make the pin-lock systems more desirable.

Reconditioning a Canister

It is not usually for a used canister to have an abundant amount of strapping tape and product or safety labels attached to its exterior. These can be easily removed by using a straight edge razor. The glue is more difficult to remove but this can be accomplished by the use of alcohol or lighter fluid. A household detergent and hot water will remove the gummy residue that remains after this procedure. A scotch-brite pad can be used on the stainless steel exterior to remove the scuff marks from the use by the bottling companies.

The lid O-ring should be changed because the flavor of the soft drink will often permeate the rubber. Changing this O-ring requires no instructions.

The O-rings on the plugs should not be effected by the soft drink flavor but could have been in use for such a extended period of time or exposed to such changes in temperature and weather that they could have become cracked or brittle. If this condition exist, it could cause the beverage or gas disconnects to leak. These O-rings can be merely cut off with a sharp knife. The new O-ring simply slides over the top of the plug into the O-ring channel.

The pick-up O-rings can be much harder to replace. This O-ring is located by removing the plug. On the ball-lock canisters, this can be accomplished by using a deep-well socket and a ratchet. On the pin-lock canisters, a special tool that slides over the plug without damaging the pins that extend from it is required. If you don' t have access to this tool, trying to remove the plugs on this type canister could damage them beyond repairable condition. Once the plug is removed, the pick-up stems can be removed with upward pressure from the inside of the canister.

The Disconnects

Disconnects will either be flared (with threads) or barbed. The flared disconnects screw into a hose adapter which inserts into the hose and allows for easy and quick customizing of the CO2 system and all the options that are derived from it.

Barbed disconnects limit your options because the barb has to insert directly into the hose itself. This prevents the user from changing the disconnects as might be desired to perform certain task.

The pin-lock disconnects has a collar that is notched to slide down on the pins on the plugs. While unattached, the collar will rotate freely around the bottom of the disconnect. When the notches in the collar are lined up with the pins on the plug, the disconnect can easily be pressed down onto the plug and the collar twisted to lock onto the pins which insures a air-tight fit. Detachment is equally simple.

The ball-lock disconnects also has a collar around its bottom, as well; however, the collar doesn't rotate; it slides up the disconnect to allow four (4) small ball-bearings to lock onto the plug while the disconnect is being pressed on to the plug. When the collar slides back into its natural position, the disconnect locks onto the plug giving you a air-tight connection.

The Beverage Set-Up

The beverage disconnect is attached to the beverage hose, normally around two (2) feet in length. The other end of the hose is attached to the spigot.

The Gas Set-Up

The gas disconnect attaches to the gas hose, normally two (2) to three (3) feet in length. The other end of the gas hose may have a hose adapter attached to it which allows it to be attached to a flare fitting on a CO2 regulator OR it will be attach directly to the regulator. The attachments to the gas hose should be secured by hose clamps to prevent gas leaks. If the gas hose attaches to a flare fitting on the regulator, a tapered washer is required to prevent gas leaks since this will be a metal to metal contact point otherwise.

The CO2 Cylinder

The CO2 cylinder is usually made of aluminum or steel in sizes from 2, 5, 10, 20 and 50 pounds. The 5 pound cylinder is the most common size included in most keg systems, while a 20 pound cylinder is the most readily available as used equipment.

The 5 pound cylinders, when filled with CO2, will contain enough gas to dispense anywhere from 10 to 30 kegs. These estimates will be dependent on 1) your ability to prevent gas leaks. 2) carbonation techniques, 3) and the dispensing pressure.

The CO2 that is used to fill the tanks can be obtained locally at any of a number of different businesses. In the Yellow Pages, you can find welding suppliers or fire extinguisher dealers that can fill the tanks. Prices can vary greatly, so it is wise to check by phone as to the rates. The availability of have the tank filled while you wait is also a service that might interest you. Some businesses fill tanks on certain days of the week or even during certain times of the day. In smaller communities, the local business may have to send the tank to another supplier for the refill. All these things can things can be determined by making a few phone calls.

Periodically, every 5 years in most states, the tank has to hydrostatically tested for your protection. This procedure will take more time, and it is usually necessary to leave the tank over night. While the test is inexpensive, its biggest drawback is that it will deprive us of our wonderful hand crafted beer until it is completed.

Leaks are the number one cause of empty CO2 tanks in home use. The most likely locations for leaks, are the connections in the gas line. A little soapy water sponged onto these connection points will indicate the escape of gas by bubbling activity. Other position that are most prone to leaks are where the regulator attaches to the CO2 tank and where the gas line attaches to the regulator.

If the gas hose attaches to the CO2 regulator, the hose adapter requires a white tapered washer and it should be changed periodically to reduce leaks if frequently detached. The connection where the CO2 regulator attaches to the CO2 cylinder is one of the most likely point of gas loss. Some of the newer regulators have a semi-permanent washer while others require the insertion of a replaceable one. The replaceable washer can be made of rawhide or nylon. Leaks can usually be corrected by additional tightening.

Leaks where the disconnect attaches to the gas hose can be easily detected by simply dipping the attached disconnect into a glass or pot of water with the line pressure set at normal dispensing levels. Flared (threaded) disconnects have a built-in tapered washers and therefore reduce the chance of leaks if tightened properly. Hose clamps will reduce the potential loss of gas if used when attaching tubing adapters or barbed disconnects.

Leaks around the lid are not unusual especially as the lid O-ring ages and flattens from extended use. Again, a soapy sponge is the easiest way to detect such leaks. A realignment of the lid is usually all that is necessary, even though such adjustments can be somewhat frustrating at times. After the lid is attached, a line pressure of 20 pounds or more may be necessary to seal the lid.

The CO2 Regulator

The CO2 regulator will be either a single-gauge or two-gauge. The gauge that is common to both types of regulators is the line pressure gauge which registers the measures the dispensing pressure in P.S.I.'s (pounds per square inch). This gauge is easier to read and adjust if it measures 0-30 or 0-60 P.S.I.. The line pressure can be changed by an adjustment screw on the regulator.

The second gauge on the two-gauge regulator is the tank pressure gauge. This gauge is mistakenly thought to read the amount of pressure that remains in the tank. However, CO2 maintains the same tank pressure whether it contains 20 pounds of CO2 or 1 pound. It will, however, forewarn you of the impending loss of CO2 by a rapid drop in pressure as the last of the liquid CO2 is exhausted. The remain CO2 gas in the tank can be sufficient to dispense a large portion of a 5 gallon batch if a leak is not the culprit.

Preparing a Canister for Filling

The following procedures assume that the gas set-up, the beverage set-up, the CO2 regulator and tank are ready for use. But before the canister can be filled with our beer, it must be cleaned and sanitized.

A carboy brush and hot water can be utilized to remove any build up of sediment that remains from a previous batch of beer. Once the canister has been cleaned, it should be sanitized by using a solution of iodophor, B-Brite or T.S.P. (tri-sodium phosphate).

Bleach should never be used to clean stainless steel because it is corrosive and will cause it to rust with continual use.

Pour about a gallon of sanitizing solution into the canister and attach the lid. Shake and turn the canister so that all inside surface areas are contacted by the solution. Now, attach the beverage and gas set-ups and adjust the P.S.I. rating to a level that will force the solution out through the spigot. Once this process is completed, repeat the procedure using water to eliminated the presents of the sanitizer.

Failure to properly rinse the sanitizer could kill the yeast and could also be a health concern.

Kegging Your Beer

The best brewing system for producing quality draft beer is one that incorporates a glass secondary in the brewing process. After the beer is transferred to the secondary, it is advisable to use a fining agent such as polyclar or gelatin to achieve maximum clarity prior to kegging the beer.

I recommend the use of polyclar due to its multi-purpose character. Polyclar will remove the solids in suspension, as well or better than gelatin. But it is also an anti-oxidant (prevents oxidation) and a chill haze preventative. Neither polyclar or gelatin should be added to the secondary if the air-lock activity is timed at greater than one (1) bubble to minute.

Once the beer is ready and the keg has been sanitized and rinsed, it can be racked directly into keg from the secondary fermenter. Fill the keg to within two (2) inches from the top.

Priming the Beer - Artificially

Having transferred the beer into the keg it is again desirable to add a fining agent. In this situation, gelatin is the fining that is the most desirable. It will settle out any solids that were picked up in the racking process and help to create a more solid sediment bed. Having added gelatin, attach the lid and the gas set-up. Adjust the P.S.I. rating to 20 on the regulator and turn on the gas. Check for leaks as previously described. Correct as necessary. When a good seal has been achieved, bleed off the CO2 in the head space by opening the valve on the pressure release lid or removing the gas disconnect and depressing the center of the gas “plug”. Hit the keg with 20 pounds of pressure again and bleed it off two (2) more times to purge the keg of oxygen.

Finally, raise the regulator pressure (in accordance with the table in appendix A) to the desired level and leave for three (3) days. By leaving the gas hooked up over a period of time, we can instill carbon dioxide into the beer.

After the third day, turn off the gas. Bleed off the head space pressure. Adjust the regulator pressure to 6-12 P.S.I. (the normal dispensing pressure) and draw off 3-4 ounces of beer. This first draw will contain mostly sediment. Pour it out. Draw another glass of 3-4 ounces of beer. Sample this one to determine if the carbonation is right. If so, you can leave the pressure in the 6-12 range. If not, raise the pressure back up to the previously determined level and leave for another 1-2 days before checking the carbonation again.

Artificially carbonating your beer tends to achieve large bubbles that quickly dissipates and you also use more CO2. BUT when you use the fining agents, this method of carbonating will achieve clarity comparable to commercial beer without needing to be filtered and your beer will run clear after 2-3 glasses of beer until you run out.

Priming & Cask Conditioning - Naturally

With this method, after transferring the beer into the keg, add 1/3 to 1/2 cup of corn sugar that has been dissolve in a cup of water by boiling. Adjust the P.S.I. rating to 20 on the regulator and turn on the gas. Check for leaks as previously described. Correct as necessary. When a good seal has been achieved, bleed off the CO2 in the head space by opening the valve on the pressure release lid or removing the gas disconnect and depressing the center of the gas “plug”. Hit the keg with 20 pounds of pressure again and bleed it off two (2) more times to purge the keg of oxygen.

Disconnect the gas and leave for 10-14 days at room temperature to achieve carbonation. After which the keg should be refrigerated for 2-3 days. Bleed off the head space pressure. Adjust the regulator pressure to 6-12 P.S.I. (the normal dispensing pressure) and draw off 3-4 ounces of beer. This first draw will contain mostly sediment. Pour it out. Draw another glass of 3-4 ounces of beer. Sample this one. If the carbonation is right, you can leave the pressure in the 6-12 range and work it in to your dispensing schedule.

If the carbonation level is lower than desired, you will need to force carbonate the beer for 1-2 days at 20 P.S.I. to achieve more carbonation.

With this method, the beer tends to be cloudier and you will tend to a dispense a greater % of your total batch of beer before you achieve the type of clarity that is achieve by force carbonating after 2-4 glasses.


  Carbonation Chart in Volumes of CO2


















Pounds Per Square Inch (P.S.I.)
  7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
37 2.15 2.24 2.34 2.42 2.52 2.62 2.72 2.80 2.90 3.00                           
38 2.10 2.20 2.29 2.38 2.47 2.57 2.67 2.75 2.85 2.94                           
39 2.05 2.15 2.25 2.34 2.43 2.52 2.61 2.70 2.80 2.89 2.98                         
40 2.01 2.10 2.20 2.30 2.39 2.47 2.56 2.66 2.75 2.84 2.93 3.01                       
41 1.97 2.06 2.16 2.25 2.35 2.43 2.52 2.60 2.70 2.79 2.87 2.96                       
42 1.93 2.02 2.12 2.21 2.30 2.39 2.47 2.56 2.65 2.74 2.82 2.91 3.00                     
43 1.9 1.99 2.08 2.17 2.25 2.34 2.43 2.52 2.60 2.69 2.78 2.86 2.95                     
44 1.86 1.95 2.04 2.13 2.21 2.30 2.39 2.47 2.56 2.64 2.73 2.81 2.90 2.99                   
45 1.82 1.91 2.00 2.08 2.17 2.26 2.34 2.42 2.51 2.60 2.68 2.77 2.85 2.94 3.02                 
46  1.88 1.96 2.04 2.13 2.22 2.30 2.38 2.47 2.55 2.63 2.72 2.80 2.89 2.98                 
47  1.84 1.92 2.00 2.09 2.18 2.25 2.34 2.42 2.50 2.59 2.67 2.75 2.84 2.93 3.02               
48  1.80 1.88 1.96 2.05 2.14 2.21 2.30 2.38 2.46 2.55 2.62 2.70 2.79 2.87 2.96               
49    1.85 1.93 2.01 2.10 2.18 2.25 2.34 2.42 2.50 2.58 2.66 2.75 2.83 2.91 2.99             
50    1.82 1.90 1.98 2.06 2.14 2.21 2.30 2.38 2.45 2.54 2.62 2.70 2.78 2.86 2.94 3.02           
51      1.87 1.95 2.02 2.10 2.18 2.25 2.34 2.41 2.49 2.57 2.65 2.73 2.81 2.89 2.97           
52      1.84 1.91 1.99 2.06 2.14 2.22 2.30 2.37 2.45 2.54 2.61 2.69 2.76 2.84 2.93 3.00         
53      1.80 1.88 1.96 2.03 2.10 2.18 2.26 2.33 2.41 2.48 2.57 2.64 2.72 2.80 2.88 2.95 3.03       
54        1.85 1.93 2.00 2.07 2.15 2.22 2.29 2.37 2.44 2.52 2.60 2.67 2.75 2.83 2.90 2.98       
55        1.82 1.89 1.97 2.04 2.11 2.19 2.25 2.33 2.40 2.47 2.55 2.63 2.70 2.78 2.85 2.93 3.01     
56          1.86 1.93 2.00 2.07 2.15 2.21 2.29 2.36 2.43 2.50 2.58 2.65 2.73 2.80 2.88 2.96     
57          1.83 1.90 1.97 2.04 2.11 2.18 2.25 2.33 2.40 2.47 2.54 2.61 2.69 2.76 2.84 2.91 2.99   
58          1.80 1.86 1.94 2.00 2.07 2.14 2.21 2.29 2.36 2.43 2.50 2.57 2.64 2.72 2.80 2.86 2.94 3.01 
59            1.83 1.90 1.97 2.04 2.11 2.18 2.25 2.32 2.39 2.46 2.53 2.60 2.67 2.75 2.81 2.89 2.96 3.03
60            1.80 1.87 1.94 2.01 2.08 2.14 2.21 2.28 2.35 2.42 2.49 2.56 2.63 2.70 2.77 2.84 2.91 2.98
  7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30