1 gallon milk (not ultra high pasturized)
1/4 tsp citric acid
1/4 cup cool water
1/4 tsp liquid rennet or 1/4 rennet tablet mixed with 1/4 cup non-chlorinated water
1 tsp non-iodized salt (optional)
Mix citric acid with water, place in large stainless steel pot. Slowly add milk and stir constantly as you add milk.
At barely below medium-low burner, SLOWLY heat milk to 90 degrees. Stir occassionally so milk does not scorch.
When the milk is at 90, turn off heat and stir in rennet. Stir from the bottom for about 30-60 seconds. Then put lid on pot and let sit for 10 minutes. Do not stir again.
After 10 minutes, check to see how solid the curd is. The whey should also be clear and a greenish color. If you can pull it away from the side, take a long knife and cut the curd into 1" cubes. With a slotted spoon, scoop out the curd into a collander.
Drain the curd really well (this may take 15 minutes) and put into a microwave proof bowl and microwave on high 1 minute. With kitchen gloves on (this is going to be really hot) knead like you would bread dough and drain excess whey. Now put back into microwave for approximately 30 seconds. knead and drain the whey. Microwave for another 30 seconds.
At this point you are ready to knead, stretch and add the salt. The mozz should now be stretchy and hot. Knead in the salt slowly and then start stretching it. You may need to reheat for another 30 seconds if it cools down.
When the cheese is shiny, pinch off balls and make into rounds (a lot like when you are making dinner rolls) and drop into cool water. The cheese is ready to eat right now, but will keep up to 3 days in fridge, but the sooner the better.