Hey folks,

Welcome to this edition of Talk To Me Tuesdays! Today, I'm going to delve just a little deeper into cheese production. Shay left me a comment/question regarding cheese following my posts on whey and Daiya cheese last week. Shay is a vegetarian transitioning into veganism and has been only eating cheddar cheese and wanted to know specifically if this type of cheese has rennet. Based on the research I have done, yes it does. I told Shay I would shed a little more light on cheese production today, so for Shay and for you, here we go!


Cheese is made up of proteins and fat from milk, usually coming from cows, buffalo, goats, or sheep. Cheese is produced by coagulation (changing from a liquid to a thickenend mass- curdle) of the milk protein casein (a phosphoprotein that makes up 80% of proteins in cow milk and cheese, many products contain casein- if so it is not a vegan product). In most cases, milk is acidified and addition of the enzyme rennet causes coagulation. The solids are separated and pressed into final form.

A step that is required in making cheese is separating milk into solid curds and liquid whey. This is usually accomplished by souring the milk and adding rennet.

Rennet is a natural complex of enzymes produced in the mammalian stomach to digest the mother's milk and it is often used in the production of cheese. The modern method of producing rennet is deep-frozen stomachs are milled and put into an enzyme-extracting solution. Crude rennet extract is then activated by adding acid. Enzymes in the stomach are produced in an inactive form and are activated by the stomach acid. (makes you want to reconsider that slice of cheesecake doesn't it?!).

Since there has been a decrease in available proper stomachs for the production of rennet in recent years, alternative methods of producing rennet have been put into place including vegetable rennet, microbial rennet and genetically engineered rennet. Due to some inconsistencies and flaws in vegetable and microbial rennet, the most often used rennet currently is the genetically altered rennet.

Due to the development of genetic engineering, it became possible to use cow genes to modify some bacteria, fungi or yeasts in order to make them produce chymosin(also called rennin, this is produced by the cow, in the lining of fourth, final, chamber of its stomach). Chymosin was the first artificially produced enzyme to be allowed by the U.S. Food and Drug Administration. In 1999, about 60% of U.S. hard cheese was made with genetically engineered chymosin and has up to 80% of the global market share for rennet. By 2008, roughly 80 - 90% of commercial cheeses made in the U.S. were produced using GMO-based rennet.

Now, to address cheddar cheese more specifically for Shay:

Cheddar Cheese: After heating, the curd is kneaded with salt and is then cut into cubes to drain the whey, then stacked and turned. The curds and whey are then separated using rennet.

So, based on the above information, it is safe to say that the use of rennet is a required step in cheese production. I had no idea all that was involved in making cheese (and this is just the summarized version). As I said in an earlier post, I probably wouldn't have struggled as much with giving it up had I researched all this information. I realize that oftentimes we don't take the time to really learn about what we put into our bodies because we tend to go along with what we were taught and what is status quo.

However, as I began my journey and started digging deeper, I now know how important it is to be knowledgeable about the food choices we make. I know that everyone is not going to be vegan, but I thoroughly believe in this lifestyle and want to be a vessel to shed light on the accessibility veganism. This is why I choose to bring you this type of information so you can make educated choices in the event you aren't seeking it out for yourself. My plight is to help take some of the legwork out for you! :-) So, I hope I have shed some light on cheese for you. There are great alternatives like Daiya that exist- no calf stomachs required!

Thanks for your question Shay! Please keep them coming- this goes for everyone!