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

Combine sugar, root beer extract and 1 gallon warm water in 5 gallon
tall cooler. 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.