I Just Learned Parmesan Isn't Vegetarian, And I Had No Idea

Like many of us, I’ve dabbled with vegetarianism and even had a brief vegan phase. 

About 5-7% of the UK population are vegetarian, YouGov says, with 64% having started the lifestyle in the past five years. 

While veggie dining options might have moved on from the sad mushroom burgers of years gone by (why was it always so soggy?), cheeses like the mozzarella on a margarita pizza have always seemed like a safe bet. 

But it turns out that Parmesan, a common pasta add-in, doesn’t count as vegetarian at all.

Why not?

According to the culinary site Bon Appetit, it has to do with an ingredient used during the traditional cheese processing method. 

In Europe, the cheese has to be made in certain regions of Italy according to its original Parmigiano Reggiano methods to be sold as Parmesan. 

This ancient recipe involves a substance called rennet. This enzyme clots the milk and makes the cheese thicker. 

Rennet is used in lots of cheeses including cheddar, but for traditional Parm, it’s made from the lining of the fourth stomach of calves. 

“Calf stomachs are ground and then soaked in an enzyme extraction solution,” food scientist Dr Topher McNeil told Bon Appetit. 

How is vegetarian rennet made?

Vegetarian rennet, which Bon Appetit says is what 90% of commercial cheese is made with, recreates the chymosin traditionally gotten from calves’ stomachs. 

Alexander Anton, secretary general of the European Dairy Association, told FoodNavigator that “Nowadays most British cheese is suitable for vegetarians because it is made using a non-animal renneting agent.”

The Spruce Eats says this agent can come from soaking plants like cardoon thistle, artichokes, or nettles. 

Another way of making plant-based rennet is by getting mucor, or a microbial fungus, into milk. 

Your cheese’s label should tell you whether or not it’s vegetarian, but for most non-Parm cheeses, you’re likely in the clear.