Step 2: Begin the mozzarella
Dissolve 1 1/2 teaspoon citric acid in 1 cup water
Pour the gallon of milk into the pot, and add the citric acid water while stirring. Continue to stir while heating the mixture to 90°F
Take off the heat, add the dissolved rennet, and stir vigorously for 30 seconds. Cover and let sit for 5 minutes.
Cut the curds in about 1" strips, then cut cross-wise and again at an angle. Your goal is to get 1" chunks of cheese. Don't worry if it doesn't work - mozzarella is very forgiving.
Heat while stirring to 105°F, then take off heat and continue to stir for 3-5 minutes longer.