Cornelius kegs, commonly called corny kegs, were originally used in the soft drink industry for the soda fountains. The Cornelius kegs were filled with syrup and pressurized by CO2 which would force the syrup up to the drink dispenser and allow it to be mixed with carbonated water giving you your coke or Pepsi.
The soft drink industry still uses Cornelius kegs for pre-mix setups, but the industry has gone to a "bag in the box" system for the syrup dispensers. That change has been a boon for the home brewer as it has made available probably the single best container for home brewing. The "used" Cornelius keg that is a corny keg that has been taken out of circulation and made available to home brewers is the single best value you can find for a 5 gallon stainless steel keg.
Pin Lock Cornelius Keg or Ball Lock Cornelius Keg?
Cornelius kegs come in two different styles. One is the pin lock style and the other is a ball lock style. The pin lock and ball lock both refer to the way the quick disconnects attach to the Cornelius keg.
Pin Lock Cornelius Kegs: Pin lock Cornelius kegs are also known as Coke kegs, because this style was used exclusively by the Coca Cola Company and use a pin-lock style disconnect to connect and disconnect to the liquid and gas lines. Pin lock Cornelius kegs have small pins around the perimeter of the post. The disconnects are pressed on the post and the collar rotates to lock onto the pins.
Ball Lock Cornelius Kegs: Ball lock Cornelius kegs are also known as Pepsi kegs; this style was used by Pepsi but was also used by everyone else so this style became more popular than the pin lock. Ball lock Cornelius kegs use a ball lock disconnect to connect and disconnect to the liquid and gas lines. Ball lock disconnects lock on by lifting the collar up, pushing it on the post and then releasing the collar.
Other than the connections there are a couple of other differences you may find between the two styles. The first difference is the dimensions. A standard Pepsi style keg is about 3” taller and 1” smaller in diameter than a standard coke style keg.
The second thing you will find is that the Pepsi style Cornelius Kegs typically have a pull ring relief valve in the center of the lid while the coke style Cornelius Kegs have a “fuse” type relief valve. In the case of the Coke style Cornelius Keg most people just depress the gas side post to relieve pressure from the keg.
Cornelius Kegs - pin lock or ball lock? The choice really comes down to personal preference or in many cases what is available at the time. You can purchase either the pin lock style or the ball lock style from the CornyKeg web site. Note that most of the ball lock kegs sold on the CornyKeg web site are converted pin lock style kegs.
In addition if you have a mixed bag now and would like to make them all ball lock kegs you can convert any Firestone, Spartanburg or Hoover style pin lock keg to a ball lock keg using our pin lock/ball lock conversion kit.