The Role of Rennet in Cheesemaking
To understand non-animal rennet cheese, it is first necessary to grasp the function of rennet itself. Rennet is a complex of enzymes, primarily chymosin, that causes milk to coagulate and separate into solid curds and liquid whey. This coagulation is a critical first step in the production of most cheeses. Traditionally, rennet was sourced from the stomach lining of young, unweaned ruminant animals like calves, lambs, and goats. This practice, however, makes the resulting cheese unsuitable for vegetarians. The search for a suitable alternative led to the development of several non-animal rennet types, transforming the cheese industry and expanding options for those with specific dietary needs.
The Three Main Types of Non-Animal Rennet
Non-animal rennet encompasses several categories of milk-coagulating enzymes, all of which are derived from sources other than animal stomachs. The three primary types are:
Microbial Rennet
This type of rennet is produced by fermenting specific fungi, molds, or yeasts in a controlled laboratory setting. A common source is the fungus Rhizomucor miehei. The microorganisms produce enzymes that perform the same function as animal rennet, coagulating the milk effectively. Microbial rennet is widely used in commercial cheese production due to its consistency, cost-effectiveness, and long shelf life. While highly effective, some artisan cheesemakers note that microbial rennet can occasionally contribute a slightly bitter flavor to hard cheeses that undergo a long aging process.
Fermentation-Produced Chymosin (FPC)
FPC is the most common form of non-animal rennet used in modern commercial cheese manufacturing, accounting for up to 90% of the market share. It is created by introducing the specific genes for chymosin (the key enzyme in animal rennet) into microbes like yeast or fungi. The genetically modified microbes are then fermented to produce pure chymosin, which is harvested for cheesemaking. Because FPC produces chymosin identical to that found in animal rennet, it is highly consistent and effective, and it does not impart any bitterness, even in long-aged cheeses. The final product contains no genetically modified organisms, only the chymosin enzyme, making it a vegetarian-friendly option.
Plant-Based Rennet
Historically, cheesemakers have used plant-derived enzymes from various sources to coagulate milk. True plant-based rennet is extracted from plants such as cardoon thistle, figs, and nettles. This type of rennet is still used today in traditional cheesemaking in regions like Spain, Portugal, and Italy. However, plant-based rennet is less common in modern, large-scale production. It can be more inconsistent than microbial or animal rennet, and the enzymes may produce a softer curd. Some plant sources, particularly thistle, may also add a distinct flavor to the cheese, which can be desirable for certain traditional varieties.
How to Identify Non-Animal Rennet Cheese
For consumers, navigating the dairy aisle to find a non-animal rennet cheese requires careful attention to labeling. The source of rennet is not always explicitly stated on the packaging, but there are several clues to look for:
- Ingredient List: The most direct method is to read the ingredient list. Look for terms like "microbial enzymes," "vegetarian rennet," "vegetable enzymes," or "non-animal enzymes". If the label simply says "enzymes" without specifying the source, the cheese may contain either animal or non-animal rennet. In this case, it's best to contact the manufacturer or check their website for clarification.
- Certified Labels: Look for vegetarian-friendly certification logos, such as the Vegetarian Society's 'V' label, which guarantees the product contains no animal-derived ingredients, including rennet.
- Kosher Certification: Cheese with a kosher certification symbol (e.g., OU or K) is always made with non-animal rennet. This is because kosher law prohibits mixing meat and dairy products, and animal rennet is considered a meat product.
- Company Information: Some brands, like Tillamook, Cabot, and Organic Valley, use non-animal rennet for most of their products and often specify this on their packaging or website. Checking the company's FAQ page online can provide definitive information.
- Product Type: Be aware that many soft cheeses, like fresh mozzarella, ricotta, cottage cheese, and cream cheese, do not require rennet at all and are coagulated with acid instead, making them inherently vegetarian.
Non-Animal Rennet vs. Animal Rennet: A Comparison
| Feature | Animal Rennet | Non-Animal Rennet | Key Difference |
|---|---|---|---|
| Source | Stomach lining of young ruminants (calves, lambs) | Microorganisms (fungi), plants (thistle), or genetically engineered microbes (FPC) | Ethical sourcing and suitability for vegetarian diets |
| Cost | More expensive due to limited animal source | Generally less expensive, especially microbial and FPC types | Economic efficiency and production scale |
| Consistency | Can have natural variations due to animal source | Highly consistent, especially FPC, due to controlled lab production | Predictability and quality control |
| Flavor Impact | Often contributes a complex, traditional flavor profile, especially in aged cheeses | Can cause bitterness in long-aged cheeses (microbial rennet); neutral flavor (FPC) | Potential for flavor development during aging |
| Suitability for Aging | Preferred for many long-aged cheeses due to desirable enzyme breakdown | Most suitable for fresh and younger cheeses; FPC is excellent for aged cheeses | Effect on cheese texture and flavor over time |
| Certifications | Not suitable for vegetarian or kosher certification | Suitable for vegetarian, kosher, and halal certifications | Adherence to dietary restrictions |
Conclusion: A Growing Dietary Choice
As consumer awareness and demand for vegetarian-friendly products grow, non-animal rennet has become a standard in the cheesemaking industry. The transition to microbial and fermentation-produced chymosin has allowed for the creation of consistent, high-quality cheeses that meet diverse dietary needs without compromising flavor or texture, especially in the most common, shorter-aged varieties. While some traditional, protected-origin cheeses still require animal rennet by law, the vast majority of cheeses available in supermarkets today are produced with non-animal alternatives. By checking labels for terms like "microbial enzymes" or "vegetable rennet," seeking out certified kosher products, or consulting specific brand information, consumers can make informed choices that align with their personal nutrition and ethical preferences. This development ensures that a delicious and wide variety of cheeses remains accessible to everyone, including those following a vegetarian lifestyle.
Examples of Cheeses Often Made with Non-Animal Rennet
- Cheddar: Many large commercial brands like Tillamook, Cabot, and Organic Valley use non-animal rennet.
- Mozzarella: A large portion of fresh mozzarella and pizza-style mozzarella uses microbial or FPC rennet.
- Gouda: Many producers, including Henri Willig, offer vegetarian versions of Gouda.
- Monterey Jack: Commonly produced with non-animal rennet by brands such as Tillamook and Organic Valley.
- Swiss: Kraft and Tillamook offer Swiss cheese made with non-animal enzymes.
- Asiago: BelGioioso offers Asiago made with non-animal rennet.
- Feta: Many brands, including Whole Foods' 365, produce feta with non-animal rennet.
