Why mozzarella cheese doesn’t stretch on pizza?

Last Updated on January 17, 2024 by Aaron

Mozzarella cheese is a type of pasta filata, which is an Italian cheese that is made from stretched curd. The name “mozzarella” comes from the word “mossa,” which means “to move.”

This type of cheese gets its stretchiness from the hot water bath that it is dipped into after it is formed.

The hot water bath causes the proteins in the cheese to become elastic, allowing it to stretch and pull when heated. This is why mozzarella cheese is so popular for pizza; it melts into a smooth layer of stringy, gooey goodness as it cooks. Its ability to stretch also makes it an ideal choice for dishes like lasagna, where it helps to bind the layers together.

Why your mozzarella doesn’t stretch?

The stretchiness of mozzarella cheese is affected by various factors such as acidity, milk composition, calcium level, stretching time and temperature. One of the most likely reasons for homemade mozzarella cheese not to stretch is the acidity level. If the acidity level is too high or too low, the proteins in cheese won’t be able to bind together correctly and it won’t be as stretchy.

If you are using acids to set the cheese, such as vinegar, citric acid or lemon juice, the acidity is best to adjust between 5.5 to 5.7 in order to ensure your mozzarella cheese has maximum stretchiness. Also, do expect the cheese not to brown a lot. Acid-curdled cheese doesn’t stretch as good as the rennet mozzarella, that’s because rennet enzymes will cleave the casein ‘hairs’ which resulted in stronger interconnected casein network. The stronger the bonds, the more the cheese stretches.

In contrast, if you are using rennet in making your mozzarella, you should expect a pH between 5.0 to 5.2, which is higher acidity. It will produce a cheese with lower moisture and does better in browning.

In addition to acidity and calcium levels, a process of stretching the curd in hot water is an important step to plasticize the cheese. This will rearrange the protein matrix into a single-directional fibrous structure, which will facilitate the hydration of the calcium phosphate bridge to occur.

Furthermore, we have the milk composition to consider. Most of the milk in the supermarket are standardized and pasteurized. It will significantly reduce the flowability and stretchability of the mozzarella. If allowed, use raw or thermized milk for better results, and also taste better.

And finally, the stretching in hot water at 80-85 ºC. It takes experience to know the right timing to reach the desired consistency. You can watch this youtube video showing an Italian mozzarella master doing the pasta filata the correct way.


  1. MakeCheese.ca – the science behind mozzarella – why it stretches?
  2. Gonçalves MC, Cardarelli HR. Mozzarella Cheese Stretching: A Minireview. Food Technol Biotechnol. 2021;59(1):82-91. doi:10.17113/ftb.
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