It’s amazing to think that from the simple ingredients of milk, rennet and salt, comes the most varied and delicious selection of cheeses. The transformation of milk into cheese is one of the most extraordinary human discoveries. An age-old tradition dating back to around 8,000 BC, when cheese was probably first made accidentally, during the same time as the domestication of crops and animals. The basic stages of cheesemaking remain the same, and yet from these simple ingredients come an astounding variety of cheeses.

What makes cheese so delicious?

Flavours vary drastically, from the rich roundness of harder cheeses, to fruity, spiced notes of blues and the sharpness of feta and halloumi. Did you know that flavours are influenced by what the cows, sheep, goats or buffalo have eaten and how the cheese is produced? For example, many hard cheeses, such as cheddars, gain crystals of umami – or glutamic acid – as they age, creating sweet, sour and salty tastes. This array of tastes, combined with a high fat content, makes hard cheese a satisfying eat and complement to other foods, enhancing their flavours with its rich roundness. Soft cheeses, such as cottage cheese and cream cheese, retain fresh dairy flavours due to high moisture content. White mould cheeses – think Brie and Chevre – are sprayed with Penicillium candidum, to help ripen the cheese from the outside in, creating a soft buttery texture. And Penicillium roqueforti is added to some blue cheeses at various stages in the making process, which breaks down the proteins, creating blue mould and a strong taste.

Cheesy characteristics

Different ingredients and variations in processes go towards making cheeses from hard, crystalline and crumbly to soft, runny and unctuous. Softer cheese, the ones you can scoop up and dollop onto something, tend to fall into two categories: ripened and unripened. Unripened cheeses (mascarpone, ricotta and cream), involve little processing. They have very high moisture content and a mild flavour. Ripened soft, gooey cheeses (Camembert, for example) have a mould added to the surface. This in turn produces a protein-digesting enzyme. The enzyme breaks down the curd during ripening, creating a runny texture and developing the characteristic flavour. Harder cheeses undergo a more complex processing. They can be produced using a bacteria which creates microbial and chemical reactions as the cheese ages. They can also be made using bacteria which can withstand higher processing temperatures; a thermophilic starter bacteria. This method creates the gas holes that we see in Swiss cheese varieties, and also adds flavour. The texture of cheese is usually related to moisture content: the softer the cheese, the higher the moisture content; up to 80% for cottage, cream and ricotta, and as low as 13% for Parmesan.

Let’s get started…

All dairy cheese starts with milk. Once collected, it is put into a container and warmed. The first stage is separating the milk into solids and liquids. To start this process, the lactose, or milk sugar, needs to become lactic acid. Once the milk is warmed, the cheesemaker adds a starter culture that contains one or more bacteria; also known as lactic acid bacteria, because they produce lactic acid as they metabolise. The specific mix of bacteria depends on the type of cheese being produced. Once the acidity level in milk rises, the casein (one of the proteins in milk, whey is the other) can curdle. This is when rennet is introduced – of course, vegetarian rennet for vegetarians, although the traditional source was, and continues to be, derived from animals. Once added to milk, rennet makes the casein turn into curds. It’s the curds that are used to make cheese. After settling, the curdled milk is cut to release the whey. The next steps in the process really depend on what the cheesemaker is producing.

Traditional cheesemaking

When rennet is stirred into a vat of cultured milk, it causes the milk to coagulate and separate into solids (the curds) and liquid (the whey). The major component of rennet is chymosin, which helps milk to clot and separate.

What makes cheese veggie-friendly?

Many cheeses are produced using vegetarian rennet, which comes from a range of vegetable, fungal, and bacterial sources. Vegetable and plant-based rennets (such as figs, nettles, thistles and cardoons or artichokes) contain some of the protelotic qualities needed to coagulate milk. In the case of thistle rennet, the stamens are ground before being infused in warm water, which is then added to the milk in the same way as rennet. Cardoon thistle rennet works well with goat and sheep milk but with cows’ milk it can produce a very bitter cheese caused by the way it reacts with the proteins. Some fungi and moulds make their own rennet-like coagulant, often known as microbial rennet, through their own fermentation. Rhizomucor miehei for example, is a commercially available enzyme produced to be used in the food industry.

Historically cheese was made using calf rennet. The invention of a process that used genetically modified bacteria with a calf rennet gene inserted revolutionised cheese mass production in the 1980s. As this was such an important advancement, GMO vegetarian rennet is the one exception to the Vegetarian Society Approved criteria that products should be GMO-free.

So when is cheese vegan cheese?

Vegan cheese is made using a variety of seeds, nuts and nutritional yeast. It is entirely plant-based and free of milk and animal-based enzymes. The starter culture often includes grains, such as wheat and barley rice, as they contain their own population of natural bacteria. Vegan cheese is cholesterol free and usually lower in fat than cheese made from the milk of cows, sheep or goats.

De-code the label

As a consumer, it can be a challenge to identify what is, and isn’t, a vegetarian-friendly cheese. The confusion? Cheeses on supermarket shelves vary hugely in the level of information provided on the label. On a recent trip to a popular supermarket, we noticed some well-known brands carry no information to state whether a cheese is suitable for vegetarians. But, if you look at the product website, you will often find the information you need there. The vagaries of ingredient definitions also mean that often ‘milk’ is the only ingredient listed on cheese. The limitations of food labelling laws in the UK mean that labels do not require processing agents to be listed. From a vegetarian point of view, it can be unclear as to whether animal-based rennet has been used.

At the Vegetarian Society, we know too well it can be time consuming to work our way through labels, that’s why we’ve done it for you and why the Vegetarian Society Approved vegetarian and vegan trademarks are so helpful. As they allow you complete confidence in a product being suitable for vegetarians or vegans. So, next time you’re contemplating a slice or two for a BBQ, or a wedge of something for a dinner party, look out for the Vegetarian Society Approved trademarks.

Is Parmesan vegetarian?

No it is not. While you can buy vegetarian Italian-style hard cheese and variations of others which are suitable for vegetarians, Parmigiano-Reggiano, or Parmesan, is always made using animal rennet. Parmigiano-Reggiano is a Protected Designation of Origin (PDO mark) marked product. A guarantee recognised under EU laws and regulations ensuring products are made by local farmers and artisans, using traditional methods. In the case of Parmesan, this means using calf rennet. Other cheeses which are always made using animal rennet include Grana Padano and Gorgonzola.