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Chymosin 101

Rennet vs. Chymosin: What's the Difference?

Short answer

Rennet is the coagulating product you buy; chymosin is the specific milk-clotting enzyme that does most of the work inside it. So they are not competing ingredients — one is a category, the other is an enzyme.

By Bixa Products, Editorial teamUpdated August 1, 20267 min readReviewed by Luis
Rennet (as a category)Chymosin (the enzyme)
What it isA milk-coagulating preparationA specific milk-clotting enzyme
SourcesAnimal, microbial or plantPresent in animal rennet; also produced by fermentation
Role in the vatDelivers clotting enzymes to the milkCleaves kappa-casein to destabilise micelles
How cheesemakers talk about it'Which rennet do you use?''How specific is the enzyme?'

What this means when choosing a Bixa product

Bixa Liquid Microbial Rennet and Bixa Liquid Chymosin are both liquid coagulants. The practical question is not which one is 'stronger' — it is which suits the cheese you make and the way you run your process.

  • Fresh, quick-turn styles: cheesemakers commonly start with the liquid microbial rennet.
  • Pressed, held or aged styles, and processes being standardised for scale: cheesemakers commonly look at liquid chymosin.

Coagulation is never controlled by one variable. Milk composition, temperature, pH, calcium, the cheese style and your process conditions all shape how the curd forms — the coagulant is one input among several.

Frequently asked

Is chymosin stronger than rennet?

That comparison doesn't hold, because chymosin is an enzyme and rennet is a product category. What you can compare is the clotting strength of two specific products, expressed in IMCU.

About the author

Bixa ProductsEditorial team

Educational content written by the Bixa Products team, a family-owned cheesemaking ingredient company specializing in rennet and chymosin. Technical guidance is written conservatively: where a value depends on your milk, process or product, we say so instead of guessing for you.

  • Family-owned cheesemaking ingredient company
  • 30+ years in the Latin American cheesemaking market
  • Specialists in rennet, chymosin and milk coagulation

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What Is Chymosin?

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