4 - 4 1/2 gal water
1 bottle root beer extract
In a 5 gal cooler mix together the water and sugar till the sugar is somewhat dissolved. Add the bottle of extract and mix well. Using tongs, carefully place dry ice in cooler. Mix and let the dry ice do it's magic. Stir every once in a while to keep ice from sinking to the bottom and blocking the spigot.