What is a common component in most cheeses?
Rennet, my dear reader, rennet.
What is rennet? In layperson's terms, cheesemakers add rennet—clear in color and consistency—to milk. On a more scientific note, rennet is an enzyme that attaches to the protein in milk. Together this combination of enzyme and protein separates the liquids from the solids in the mixture, where the solid component later becomes our all-time favorite—cheese. Rennet separates the curds (the cheese component) from the whey (the liquid part). Most common cheeses like cheddar, blues, bloomies, and Alpine styles include rennet in production. In contrast, fresh cheeses: ricotta, cottage cheese, cream cheese, and semi-soft/hard cheeses: provolone, and some Swiss do not. Fresh and semi-soft/hard cheeses instead use household acids, like vinegar or lemon juice, during production.
Cheesemakers source rennet from the fourth stomach of young ruminants, usually weened calves or, on occasion, lambs and goats. You may think, isn't this cruel? Unfortunately, it's part of the process. Don't despair. Alternatively, other forms of rennet are microbial or vegetarian. Fungus, mold, and yeast contain microbial rennet, whereas artichokes, thistles, and nettles contain veggie rennet. Today most California cheese companies produce cheeses with veggie rennet, think Cypress Grove, Marin French Cheese Company, Cowgirl Creamery, and many more. It's best to try cheeses that come from animal and vegetarian rennet. Afterward, you can decide whether you prefer cheeses produced in a more traditional or plant-based way.
Are you ready to become a cheesemaker? Here's some links to help you be a cheesemaker.