1 (3 oz.) bottle root beer extract
4 lbs. sugar
4 gal. water

Combine sugar, root beer extract and 1 gallon warm water in 5 gallon tall cooler (ex. Igloo). Stir until sugar is dissolved. Add 3 pounds block dry ice; this will cause mixture to bubble; add 2 gallons water and have lid ready to put on container. DO NOT put it on tight. Let bubble for about 1/2 hour and add rest of water. Root beer will bubble about 2 hours. When bubbling has stopped, root beer is ready to drink. Put in gallon plastic jugs and cap. Will keep in refrigerator for some time.