No backyard party is complete without some cold adult beverages. If you have a large number of guests attending, a keg of beer may be your best option. Kegs are more economical on a per ounce basis and are often fresher than their bottled counterparts. The major drawback of kegs is their sheer size and keeping all that beer cold.
A keg holds 15 gallons of beer. It's also pressurized to keep the beer fresh. Because of this, the beer inside doesn't stay fresh more than a day or two after being tapped. Unless you have a kegerator to keep the beer pressurized and cold, it needs to be consumed quickly. Since very few people have kegerators, and no one wants to drink warm beer, your best option is to put the keg on ice.
To ice down the keg, you'll first need a 55 gallon trash can. It's best to purchase a new one specifically for this purpose, since drinking beer from a dirty trash can is undesirable. If you're using the keg indoors, you may want to place a piece of plastic underneath the trash can to protect your floor from any spilled beer.
You'll need about eight bags of ice to put in the can to keep your keg cold. Before you place the keg in the can, however, put a layer of ice about four inches deep in the bottom of the can. Have a friend help you lift the keg into the trash can and fill the trash can with ice until it's just slightly below the top of the keg.
After filling the can with ice, pour half a gallon of water over the ice to create a slurry in the bottom of the can. This will help make the keg as cold as possible. Let the keg sit for about an hour before tapping. After the keg has been on ice for about an hour, tap it, and enjoy. You'll probably need to add more ice to the can as it melts off during the party.
Another method of keeping a keg cold is to use a kegerator. A kegerator is simply a refrigerator designed specifically for kegs. It has a tap and keeps the keg pressurized with carbon dioxide so it stays fresh, just like your local bar. Obviously, this is a more expensive option than the traditional trash can and ice method, but it's beneficial if you have a lot of parties or want to keep a keg for more than a day or two.