Cheese, Mozzarella (Cultured)

⚠ UNTESTED. My first cheese was mozzarella and I still make it, but mine is the direct-acid version — milk, vinegar, flake salt — which is a genuinely different make and lives at Mozzarella Cheese (Traditional & Quick No-Rennet). This is the cultured one, which is the obvious next thing on my bench rather than something I have already done. A briefing.

The difference between the two is not skill versus shortcut, and it is worth being exact about. Direct acidification puts you at the right pH by arithmetic: you measure citric acid into cold milk, you land on the number, and the stretch is predictable enough to do on a weeknight. Culturing gets to the same pH by fermentation, over hours, and tastes considerably better for it — the bacteria are producing flavour compounds that citric acid cannot.

So one is measured and reliable, the other is grown and better, and the second can overshoot while your back is turned.

The diagnostic detail, and the thing that makes this family worth learning: you test a golf-ball of curd in hot water, not a clock. Everything else here is ordinary cheesemaking.

Ingredients

• 1 gallon whole milk (not ultra-pasteurised)
• 1/8 tsp thermophilic culture (not mesophilic — see the directions)
• 1/4 tsp calcium chloride solution, if the milk is shop-bought
• 1/2 tsp liquid rennet, single strength, diluted in 1/4 cup cool unchlorinated water
• 1/4 cup fine salt for the brine, or 2 tsp to salt the curd in the stretch water
• Water or reserved whey for stretching, held at 170-180 F

Directions

Key ingredients

Salt

1. Ripen the milk at 90-95 F / 32-35 C, 45 to 60 minutes. 🔴 Thermophilic culture, not mesophilic. You will be at 105 F shortly and a mesophilic culture dies up there — acidification simply stops, and the recipe will not warn you. This is the substitution that ruins the most batches in the whole craft.
2. Rennet, diluted, stirred in one minute, then stop. Aim for a flocculation multiplier of about 3 — a firmer, drier curd than a soft cheese, because everything from here is about getting whey out.
3. Cut to 1/2 inch, rest 5 minutes, then stir gently while raising to 105-108 F / 40-42 C over about 30 minutes. Hold and stir until a squeezed handful of curd does not re-knit.
4. Drain, and let the curd mat. Pour off the whey, keep the curd warm at 100-102 F, and leave it as a slab. It will knit into a solid mass, and the acid develops while it does. Anywhere from 90 minutes to five hours, depending on your culture and your room.
5. ⭐ Now test, and keep testing. This is the whole skill. Cut a golf-ball of curd, drop it in water at 175 F / 80 C for a minute, and pull. If it stretches into a smooth rope two or three feet long without breaking, the batch is ready. If it tears short, wait twenty minutes and test again — that is recoverable and it is what nearly every first failure actually is. If it falls apart into shreds, you have missed it.
6. Mill and stretch. Cube the slab, put it in a bowl, pour over water or hot whey at 170-180 F / 77-82 C. Work it with a spoon, then hands, folding the mass over itself until smooth and glossy. Fold, do not tear. And stop as soon as it is smooth — every extra minute pushes fat into the water.
7. Shape and set. Pull a ball, tuck the seam underneath, drop it into iced water or cold brine. Salt either in the stretch water or with about five minutes in saturated brine for a small ball.
8. Eat it the same day if you can. Fresh mozzarella is at its best within hours.

Notes

Where this recipe came from — and what it isn’t 🔴 UNTESTED. Standard cultured method. It is not the recipe I actually use — that is the no-rennet direct-acid one, which is in the collection and which I have made for thirty years. Both are real mozzarella; they are not the same cheese.

The pH window, which is the whole family Hot water does not make curd stretch. Hot water makes curd stretch if the pH is right, and does nothing useful otherwise. As the curd acidifies, calcium leaves the casein network: too much calcium still bound and it is short and tears; too little and there is no network left and it collapses into the water. In between there is a window.

Above 5.6 it tears. 5.4 down to 5.0 it stretches, and 5.2 is the middle of it. Below 4.9 it crumbles and nothing brings it back. ⚠ A curd fermenting steadily can cross that whole window in under an hour, which is why this family has a reputation for being temperamental — the reputation is really about a cook who went to do something else.

Read the water, not just the curd ⚠ If the stretch water goes milky white, you are losing fat. That is this family’s characteristic waste and it is caused by water that is too hot, working the curd too long, or both. Clear water and a glossy ball means you stopped in time.

A pH meter is worth more here than anywhere except cheddar The golf-ball test is a real instrument and it is the one to trust, but a meter turns “somewhere in the next two hours” into a number. The two together are better than either: the meter tells you where you are, the golf ball tells you what that pH is doing to your curd today.

Variations Low-moisture: drier curd, a more thorough cook, salted harder, then a few days in the fridge. This is the correct pizza cheese and not a compromise — stretch needs intact protein, so you want it young, and low moisture makes it brown instead of flood. Buffalo milk is a different milk with far more fat and protein and is the reason the real thing tastes as it does.

Read alongside /cheese/makes/pasta-filata/ on the site.