Just like old fashioned cream soda. 
1 pack makes 20 to 40 litres - Instuctions on packet.

Zatarains is an old brand root beer that has a lot of fans. It has more of a 
sarsparilla flavor, spicy, with black licorice overtones. Makes 20L

Gnome is a mellow rootbeer with a big, round flavor. Totally subdued when
compared with Zatarains. It has a lot of followers. Makes 19 to 38L

This real creamy rootbeer blends really well with
vanilla ice cream in rootbeer floats.

This rootbeer has a holiday flavor featuring overtones of Graham 
crackers and ginger bread cookies. Good for 20L of rootbeer.