Take a one gallon glass jar or plastic milk carton (It must have a screw lid) and fill it half-full of warm water.
Using a funnel add:
2 cups sugar
2 tbsp. McCormick’s root beer extract
1 scant tsp dry yeast
With the lid screwed on, shake to dissolve sugar and yeast. Fill the jug with water to 2-3 inches from the top. Then, screw the lid back on and let sit overnight or for about 12 hours at room temperature. Then cool and drink.