I got this recipe from Keith. It's super easy and delicious.
1 - 2 ounce bottle of Root Beer Concentrate
9 1/2 cups sugar
4 1/2 gallons water
5 lbs. dry ice
Mix the first three ingredients in large water cooler, then carefully add the dry ice. Remember to not screw on the lid or you will have a huge explosion. The dry ice needs to vent!
This makes a lot of Root Beer!