This recipe, often called '30-minute Mozz' or 'Quick Acid Mozz,' is pretty popular (because of '30-Min Mozz' kits found at cheese and DIY / crafting stores) but it is also tricky. A lot of people have tried it once and flopped. The recipe ahead will steer you around some of the common pitfalls and land you at a colander full of fresh curds, ready to be stretched into beautiful balls and ropes.
Step 1: Gather Ingredients
Here's what you'll need in terms of ingredients:
2-gallons VERY FRESH cream line
(unhomogenized) milk----and I HIGHLY recommend that it is raw or only mildly pasteurized
2 and 3/4 tsp citric acid crystals diluted in 1/4 cup cool water
1/8 tsp lipase powder (optional)
1/2 tsp single-strength rennet
You can find these items at on-line cheesemaker supply stores. The rennet and the lipase will expire so pay attention to their expiration dates. The milk should be extremely fresh--so much so that all the cream at the top is still 100% liquid (not congealed into one of those 'butter pucks').
Step 2: While Milk is Cold, Add Acid
It is very important that the milk be colder than 60 degree Farenheit when you do this next step: Take the citric acid crystals and mix with the 1/4 cup cold water. Stir until they are completely dissolved. Then, while stirring, add the dissolved citric acid to the cold milk.
Step 3: Heat Milk
Bring the milk to 90°F (over medium flame) then turn off the heat. Sprinkle in lipase (optional) and allow 1 minute for it to dissolve. Then stir gently for 10 seconds.
Step 4: Add Rennet
Add the liquid rennet (I use a medicine dropper to get a more precise measurement). Stir the rennet in for 10 seconds then stop the motion of the milk. Immediately start a timer and wait for 4 minutes. After this amount of time, the milk should look like silken tofu.
Step 5: Cut the Curd
When the milk has set into a very soft gel, cut it down into columns which are roughly 2 inches by 2 inches. Immediately, you will start to see the whey weeping out of the curd.
Step 6: Stir, Heat, Drain
Stirring very gently at first, start to make gentle horizontal cuts to the curds, breaking the columns into cubes. Continue stirring to get all cubes into motion. This should take 3-5 minutes. Next, turn the heat back on to low and start to heat curds slowly to 95°F, stirring gently the whole time. It should take 10 minutes to raise the temperature from 90 to 95°F. Once at temperature, turn off the heat. Stir curds at 95°F degrees for 5 minutes more then dump the contents of the pot into a colander. Drain for ~ 20 minutes, flipping once part way through. Your curds are now ready to stretch.