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Rennet: what it is, where it’s used, vegetarian or not

Rennet is the set of enzymes that curdles milk into cheese. It was traditionally taken from a calf’s stomach, but most hard cheese today is made with microbial rennet or fermentation-produced chymosin, neither taken from an animal. Labels often say only “rennet” or “enzymes”, and when they do, Bravoora shows the source as unclear instead of guessing.

By Bravoora teamUpdated Sources checked 2 sourcesHow we check

Fresh cheese curds draining in a red sieve.

What is rennet?

Rennet is the set of enzymes that curdles milk. It was traditionally taken from the stomach lining of a calf. Most hard cheese today is made with microbial rennet, or with chymosin produced by fermentation, neither of which is taken from an animal. Labels often say only “rennet” or “enzymes”, so the source is not stated on the pack.

Where is rennet found?

  • Hard cheeses such as cheddar, parmesan and halloumi are made with rennet.
  • Feta and many soft and fresh cheeses use it.
  • Whey from rennet-set cheese is sold as whey powder and whey protein.

What are the other names for rennet on a label?

On a label, rennet can also appear as “Chymosin”, “Animal rennet”, “Calf rennet”, “Microbial rennet” or “Vegetarian rennet”.

ChymosinAnimal rennetCalf rennetMicrobial rennetVegetarian rennetEnzymes

Which diets and allergies does rennet fit?

For rennet: vegan, vegetarian and dairy-free profiles get Heads up; gluten-free, peanut-allergy, sesame-allergy, egg-allergy, soy-allergy and caffeine-free profiles get Fits you.

VeganHeads upIt can come from a calf, from microbes or from fermentation, and labels rarely say which.
VegetarianHeads upMicrobial and fermentation-produced rennet are not animal-derived; calf rennet is.
Milk allergy / dairy-freeHeads upRennet itself is not milk, but the foods that list it are almost always cheese.

A packed product can still carry a “may contain” warning, so check the pack.

Does rennet fit you?

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How does Bravoora check for rennet?

When a label says only “rennet” or “enzymes”, Bravoora shows the source as unclear instead of guessing.

How Bravoora decides, in full

More questions about rennet

Who looks out for rennet?

Rennet matters most to people following a vegetarian or vegan profile, and anyone who avoids specific animal sources.

Is rennet vegan?

It depends. It can come from a calf, from microbes or from fermentation, and labels rarely say which.

Is rennet vegetarian?

It depends. Microbial and fermentation-produced rennet are not animal-derived; calf rennet is.

Does rennet fit a milk allergy or dairy-free profile?

It depends. Rennet itself is not milk, but the foods that list it are almost always cheese.

Sources and how to cite this guide

  1. EU Regulation 1169/2011 (food information)
  2. EU Regulation 1333/2008 (food additives)

To cite this guide: Bravoora, “Rennet: what it is, where it’s used, vegetarian or not”, bravoora.app/ingredients/rennet/, updated 22 September 2026.

Spotted something wrong or missing? Tell us.

General information, not medical advice. Rules differ by country and products change, so always check the pack.

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