First gather all your ingredients and utensils.
Add the citric acid liquid and the milk to a large pan.
While stirring, slowly bring the temperature up to 95F (35C). The milk may curdle, don’t worry.
Take the milk off the heat and add the rennet liquid. Stir for 30 seconds to combine and then leave for 5 mins.
Cut the curds into small sections using a knife.
Place a colander over a large bowl and using a slotted spoon lift out the curds into the colander.
From the bowl, pour the liquid (the whey) back into the pan.
Heat some water in another pan with lots of sea salt to around 175F (80C).
Place the colander back over the bowl. Pour some of the water over the cheese curds and start to work the cheese first with a spatula and then with your hands.
The cheese will start to become plastic and stretchy. Keep moulding the mozzarella until it is smooth and shiny.
Use your hands to bring the mozzarella together. At this stage you can use it as is or store it in some of the whey liquid in the refrigerator.
Alternatively you can make it into a long sausage shape, wrap it in plastic wrap and tie off small pieces with string.