Pour 1 gallon of milk in a large bowl. Add 2 tsp. citric acid, stir constantly. Bring temperature to 88 degrees. Dissolve 1/2 tablet of rennett in 1/4 C. water then add to mixture and bring temperature to 105 degrees. Strain mixture. Then microwave for 1 minute. After cooling slightly, kneed until it becomes gum-like.