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How to Make Homemade Cheese Using Rennet (+ Herb Cheese Recipe)
Being a food scientist I have quite a bit of theoretical background in the (food) sciences. But nothing’s better than actually applying that science. Which is also the great thing about food science: it can be applied in a kitchen very easily without a lot of fancy ingredients!
After having made cheese myself once, it was time for a next ‘experiment’. Last time I made an Indian style cheese, paneer. This time I would use a different recipe and method, making a fresh herb cheese.
In a previous post I’ve digged into the details of the cheese making process, walking through the most important steps. But since I like applying the theoretical knowledge I had to make cheeses as well of course. The paneer was my first cheese making experiment, this fresh herb cheese my second. It’s not only ‘herby’, it’s also made with an enzyme instead of an acid, hence the rennet in the post title!
Cheese making kit
It was thanks to a kit I bought at a nice discount in the sales isle in our supermarket that I made a ‘rennet cheese’. The kit I bought was one from Boska. It contained the rennet that I needed (which actually was the only reason I bought the kit), but other than that it had quite a strange selection of items. In there was a lot of salt and herbs, which I would say most people have in their homes. But a cheescloth or little press weren’t in there, which I assume most people don’t have.
Luckily, I had a cheesecloth after my previous attempt to make the paneer. And my hands served as a pretty decent press.
When making cheese, one of the most important steps is curdling the milk. During this step part of the proteins form large structures resulting into soft curds which float around in the remaining liquid. It’s these curds that make the final cheese.
Milk curdles when the activity of the κ-casein is somehow stopped. This protein normally prevents the proteins from curdling. The curdling of the cheese can be induced in two ways:
- Add an acid
- Add an enzyme
Read more in the post dedicated on the cheese making process.
The enzyme that curdles
It’s the enzyme that I’ll be using today for making my cheese. The enzymes cannot be found in most supermarkets, you’ll have to go to a speciality store.
But before we rush into that, let’s take one step back. How does this enzyme work, and what is it? The enzyme that curdles the milk is called chymosin and it can be found in rennet. Rennet is made in the stomachs of various young animals. It is a mixture that contains various enzymes. Originally rennet came mostly from veal stomachs. Nowadays though the enzyme can be made in other ways. Mixtures of enzymes that cause cheese to curdle are still called rennet, even if they aren’t the original veal’s mixture.
Enzymes are catalysts
As you might remember, an enzyme is a protein, a special type of protein. Enzymes can catalyse chemical reactions. This means that they can help chemical reactions along, without actually being used up themselves.
In the case of cheese and chymosin, the chymosin cuts up the κ-casein. This ‘deactivates’ the protein, and thus: the curdling of cheese is started!
Choosing between acid and enzyme
With both the acid and the enzyme cheese can be made. They can be used individually, but a lot of recipes also cal for both. Ratios might differ as do concentrations. Both should be treated in a different way to make a good cheese, but if processed correctly can also be used simultaneously.
Enzymes denature when heated too much (often already at temperatures >40-50C). When making a cheese with enzymes the milk shouldn’t be hot when adding the enzyme, this will deactivate the enzyme. Once the milk has curdled, the milk can be heated again, the enzyme has done its job so can be deactivated (but doesn’t have to be).
On the other hand, acids works faster at a higher temperature! So you will see higher temperatures being used (as was the case with the paneer recipe).
There are differences in taste and flavour between using the two. For instance, using an acid will make the cheese slightly more acidic (less sweet), whereas the enzyme is more neutral. Apart from that, they can result in different textures, but I haven’t made enough cheese yet to be a good judge of that.
Fresh Herb Cheese Recipe
Now that we’ve discuss the theory, it’s time to get working/experimenting! Here’s the recipe for my fresh herb cheese, using rennet.
Some of the sources I used: Colorado State University, Wikipedia.
My understanding (after having written this article about cheese science: https://www.chemistryworld.com/feature/blessed-are-the-cheesemakers/6848.article) is that non-animal rennet is made by GM bacteria. So vegetarian cheese eaters are opting into GM by default if this is true. Do you know of any other ways to make rennet?
Hi Andy, thanks for your question! It led me to doing some digging and searching on the web and learning a lot more about these enzymes. Since I’m not vegan, nor explicitely against using GM for producing pure ingredients, I hadn’t looked into this before.
I’ll try to keep the answer short (but seem to have failed…) and please let me know if you think I missed/overlooked something.
Indeed I also found that most (I found sources mentioning up to 90% in the US) of the non-animal rennet is made using genetically modified micro organisms. In literature this is generally called FPC (fermentation produced chymosin). However, it seems as if there’s also an alternative, non-GM version: the microbial coagulant/enzymes. But several sources mention that this generally leads to a lower quality product. These enzymes are not necessarily the same enzymes as sit in rennet, but have a similar function.
Besides those, I read that there are several plant sources, however, these seem to be pretty hard to get a hold off (I haven’t tried myself though). I hope that gives you a satisfying answer. For some further reading I would advice:
Scientific Article: https://www.researchgate.net/profile/Lucia_Feijoo-Siota/publication/270662199_Recent_Patents_on_Microbial_Proteases_for_the_Dairy_Industry/links/56bd9bce08ae5e7ba410cef1.pdf; was one of the first articles that made the distinction between the different types clear to me
Liked this article also: http://www.formaggiokitchen.com/blog/the-rennet-story-animal-vegetable-and-microbial/
I think these suppliers supply the microbial coagulant product, thus the non-GM, but I didn’t get to asking them yet whether this is indeed the one: http://www.cskfood.com/productpages/coagulants/microbial_coagulants & http://www.chr-hansen.com/en/food%20cultures%20and%20enzymes/cheese/cards/product%20cards/hannilase
Also, regarding GMO and cheese rennet, this might be worth a read: https://blogs.scientificamerican.com/food-matters/do-gmo-opponents-have-a-problem-with-cheese/.
I know that this is 4 years and 2 days late but I just discovered that ginger contains an enzyme that can also denature k-casein and that a traditional chinese cheese uses it for this, so that might be worth looking into for anyone who stumbles across this!
That is so interesting Paulie, did not know that, thanks for sharing. We’ll have to look into that!