The Rennet Factor: Why Some Cheeses Aren't Vegetarian
Many assume all cheese is vegetarian, but that is a common misconception rooted in the traditional cheesemaking process. The key is rennet, a coagulant used to separate milk into solid curds and liquid whey. Traditionally, and still for many classic cheeses, this enzyme is sourced from animal stomachs, making the final product non-vegetarian.
What is Animal Rennet?
Animal rennet is an enzyme complex, primarily chymosin, extracted from the fourth stomach lining (abomasum) of young, unweaned calves or other ruminants. Since this extraction requires the animal to be slaughtered, any cheese made with animal rennet is not suitable for vegetarians. In the past, this was the primary way to curdle milk for cheese production, and it remains a traditional method for certain protected cheeses.
The Rise of Vegetarian Alternatives
Today, cheesemakers have several vegetarian-friendly alternatives to animal rennet, which have become increasingly common, especially in mass-produced cheeses.
- Microbial Rennet: Produced from molds, fungi, or yeast, this is the most common vegetarian alternative used today. It's a highly consistent and cost-effective option that produces excellent results, especially in younger cheeses.
- Fermentation-Produced Chymosin (FPC): This is a genetically engineered enzyme identical to the chymosin in animal rennet, but produced by microbes in a lab. It offers the same functional properties as animal rennet but is completely vegetarian and kosher.
- Plant-Based Rennet: Derived from plants like cardoon thistle, artichoke, or fig leaves, plant rennet has been used for centuries, though it is less common today. It can sometimes impart a distinct or slightly bitter flavor, particularly in aged cheeses.
Common Cheeses to Check for Animal Rennet
While many mass-market cheeses have switched to vegetarian rennet, certain traditional European cheeses, especially those with Protected Designation of Origin (PDO) status, often mandate the use of animal rennet to be authentic.
Italian Cheeses
- Parmigiano-Reggiano: Authentic Parmigiano-Reggiano is never vegetarian, as its PDO status requires the use of animal rennet. This also applies to many traditional versions of Grana Padano, Pecorino Romano, and Gorgonzola.
French and Swiss Cheeses
- Gruyère: Traditional Gruyère is made with animal rennet.
- Camembert: Many traditional French Camemberts are made with animal rennet.
- Emmenthaler: The classic Swiss-style Emmenthaler often uses animal rennet.
Spanish and Other European Varieties
- Manchego: Traditional Spanish Manchego typically uses animal rennet.
- Roquefort: Traditional Roquefort, a classic blue cheese, is generally made with animal rennet.
- Some Feta and Blue Cheeses: While some versions are vegetarian, traditional Feta and certain blue cheeses like Roquefort can contain animal rennet.
How to Identify a Vegetarian Cheese
Since food labeling laws on rennet can be inconsistent, knowing what to look for is key to ensuring a cheese is vegetarian.
Look at the Label
- Check for Vegetarian-Friendly Terms: Search for phrases like “microbial rennet,” “vegetable rennet,” or “vegetarian enzymes”. Many brands that go to the trouble of using vegetarian rennet will proudly state it.
- Identify Animal Rennet Terms: If you see “rennet,” “animal enzymes,” or simply “enzymes” without further clarification, assume it’s animal-derived.
- Find Vegetarian Logos: Look for vegetarian certification logos, such as the V-label.
Consider the Cheese Type
- Soft Cheeses: Many soft cheeses like ricotta, cottage cheese, and cream cheese are coagulated with acid (e.g., lemon juice or vinegar) and are often vegetarian. Paneer is also traditionally made without rennet.
- Kosher Cheese: Certified kosher cheese will never contain animal rennet because of the religious separation of milk and meat. Look for a K or OU symbol.
Ask the Source
If you're at a specialty cheese shop, ask the cheesemonger for clarification. They can provide specific information about the coagulant used in their cheeses. For packaged cheeses, check the manufacturer's website or FAQ page for details. Cultures for Health has a useful guide on the different types of rennet.
A Comparison of Rennet Types in Cheesemaking
| Feature | Animal Rennet | Microbial/Vegetarian Rennet | Plant-Based Rennet |
|---|---|---|---|
| Source | Stomach lining of young ruminants (calves, goats). | Produced by microorganisms like fungi or mold. | Extracted from specific plants like thistles. |
| Best For | Aged, hard cheeses; traditional recipes. | Most commercial cheeses; younger, fresh cheeses. | Some traditional Spanish/Portuguese cheeses. |
| Flavor | Fuller, more complex flavor profile. | Generally neutral in flavor impact. | Can impart a slightly bitter taste, especially when aged. |
| Consistency | Highly consistent and predictable. | Very consistent and reliable. | Can be inconsistent; results may vary. |
| Vegetarian? | No, requires animal slaughter. | Yes, completely suitable for vegetarians. | Yes, suitable for vegetarians. |
Lists of Non-Vegetarian Cheeses and Their Alternatives
Cheeses Traditionally Not Vegetarian (check labels for modern, vegetarian versions)
- Parmigiano-Reggiano
- Pecorino Romano
- Grana Padano
- Gorgonzola
- Gruyère
- Manchego
- Roquefort
- Camembert (traditional)
- Emmenthaler (traditional)
Cheeses Often Made with Vegetarian Rennet (but always check labels)
- Cheddar (mass-produced)
- Mozzarella
- Feta (some brands)
- Cottage Cheese (rennet-free)
- Cream Cheese (rennet-free)
- Ricotta (rennet-free)
- Paneer
Conclusion: Read Labels, Know Your Cheese
While a vegetarian lifestyle is becoming more widespread, the complexities of food production can lead to surprising findings, like the fact that not all cheese is vegetarian. The use of animal rennet, derived from calf stomachs, is the key factor. Many traditional European cheeses, especially those with protected status, continue to use animal rennet for authenticity. However, the rise of microbial and plant-based rennets has made vegetarian cheese more widely available. The easiest way for vegetarians to navigate the cheese aisle is to read labels carefully, look for vegetarian or kosher certification, and opt for softer cheeses that typically don't require rennet. With a little diligence, vegetarians can confidently enjoy a wide variety of delicious cheese options without compromising their dietary principles.
