Here’s how it all comes together, in plain language.

Stretchiness Starts with Acidity and Heat

Mozzarella’s famous stretch depends mainly on correct acidity and temperature. If the curd isn’t acidic enough, it simply won’t stretch. The sweet spot is a pH of about 5.2 – 5.4. Too high, and the curd breaks; too low, and it turns rubbery or sour.

Heat matters just as much. When stretching, the curd should be heated slowly to 70 – 80 °C. Below that, it won’t stretch properly. Above 85°C, the proteins tighten too much and the cheese becomes tough and dry.

Why Mozzarella Tears, Breaks, or Feels Rubber-Like

If the cheese breaks when pulled, it’s often too cold or hasn’t been stretched long enough. Stretching usually takes 5 – 10 minutes, until the curd becomes smooth, shiny, and elastic.

Rubbery mozzarella usually comes from overcooking or over-stretching. The same happens if the curd is heated for too long—anything over 30 minutes of heating is risky.

Too much rennet or calcium chloride can also cause problems. Extra rennet makes the curd overly firm, while too much calcium chloride can alter texture and even increase saltiness.

Milk Quality Makes or Breaks Mozzarella

Good mozzarella starts with fresh milk. Old milk often leads to bitterness, weak curd formation, and poor stretch. Milk that’s too low in fat can also result in dry cheese—adding a bit of cream can help.

Milk temperature at the start is important too. If it’s too cold, starter cultures won’t work properly. Warm milk helps cultures grow and develop flavour.

Sometimes milk with very high protein content can make the cheese too firm or rubbery, so balance is key.

Timing Is Everything

After adding rennet, the curd should rest for about 30 minutes before cutting. Cutting too early gives soft, fragile curds; too late, and they become dense.

Once cut, the curd shouldn’t sit around too long. Ideally, it should be stretched within 1 – 2 hours. Waiting too long can cause moisture loss and poor melting later.

Over-stirring during heating is another common mistake—it breaks curds apart and leads to grainy texture.

Moisture, Salt, and Melting Behaviour

Mozzarella should contain about 45 – 60 % moisture. Too little moisture makes it dry and hard when cooled; too much makes it sticky and weak.

Salt improves flavour, but it must be added carefully. Too much salt not only affects taste but also tightens the protein structure, making the cheese tough and overly salty.

If mozzarella doesn’t melt well, the cause is often low moisture, incorrect cultures, or poor acid development.

Stretch Tests, Floating Curds, and Practical Checks

A ready-to-stretch curd feels firm and slightly springy. In hot water, it should sink slightly but still float a bit—not fully sink like a stone.

Acidity can be checked with pH strips, but many cheesemakers still rely on taste: a mild tang means you’re close.

Grainy texture usually means the curd didn’t break down properly during cooking, while holes inside the cheese often come from gas formed during fermentation.

Cultures, Bacteria, and Hygiene

Starter cultures must be fresh and properly stored. Weak or old cultures lead to bland cheese with little flavour. Too much culture, however, can create off-flavours and excess gas.

Bad bacteria can spoil cheese without visible signs. Strange smells are often the first warning. Clean equipment, clean hands, and correct temperatures are essential.

Weather even plays a role—humidity and ambient temperature can influence curd formation more than many people realise.

Storage, Freezing, and Selling Mozzarella

Fresh mozzarella is best eaten immediately or within a few days. It can be frozen, but freezing often damages texture once thawed.

For best quality, mozzarella should be sold within a week. As it cools and ages, it naturally loses moisture and becomes firmer.

The Big Lesson

Mozzarella is simple—but precise. Small changes in temperature, time, acidity, or milk quality can completely change the result. When things go wrong, the answer is usually not “add more,” but rather adjust gently and observe carefully.

Get the milk fresh, respect the pH, control the heat, and don’t rush the stretch. Do that, and the cheese will start behaving like mozzarella should—smooth, stretchy, and ready for the braai or the pizza oven.

Contact our technical specialists for assistance with your recipe and process flow.

retha@dynamiko.co.za

technicalinfo@dynamiko.co.za