Ask Allie: Vegetable Rennet Edition!

Ask Allie is our advice column, where you can ask all your food-related questions to get digestible answers! No question is off limits!

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This week, we have just one question! That’s because this was a technical question about pre-modern vegetable rennets, and I can’t answer it quickly enough for today’s column to not be too long for y’all if I include other questions. Although the question was specific to skyr, as you’re about to see, I included some other options used in pre-modern cheesemaking while I was searching my browser history.

Allie! I'm so glad I found you! I am a teensy dairy producer making a sort of non-traditional skyr with whole goats milk. (Long story but I happened upon skyr because I originally wanted to make butter and discovered skyr would be an ideal way to use up my skim).

I found your writings on the topic so informative and helpful with regard to the history of skyr, and wondered if you could tell me some of your references, particularly the information regarding the early use of rennet. I am actually locked in a heated debate with a "cheesemaker" who claims that the use of rennet is not traditional at all but was added as a step when skyr became a commercial product because it helped with yield. From what I can gather that's not true at all!

I also have been hunting around trying to find the name -- and the recipe -- for the whey based drink that early Icelanders made. My plan is to do something similar, crafting a sort of whey soda with the liquid I gather from straining. If you have any ideas or can point me in the direction of some resources I'd be so endlessly grateful! As it is now, while my skyr is not traditional, it is very tasty. I use thistle rennet in it, which has proven to be a little challenging, and my yield is not great. But the outcome is a love child of chevre and greek yogurt, and people seem to like it!

Thanks in advance for your help, and for your incredible work!

— Lauren

This took me some time to answer, because I didn’t bookmark all my links for this and had to dig through my history. Good thing I never delete my history (this is why)! It took me several weeks to dig through my history, and while I’m certain I didn’t find everything in there, it was an extremely interesting question and I’m glad Lauren asked it.

I also forgot to answer Lauren’s question about whey drinks, which I’ll do here really quickly. Blaand and kumis are two fermented whey drinks (think boozy!). Actually, blaand sometimes is just whey without the alcohol fermentation portion of the whey journey. But it also can basically be whey beer.

Initially, while I was searching the history, I sent Lauren the following to give some alternative, non-Viking rennet sources (actually, they may well have used nettles in some cheese-making, though I haven’t seen evidence for it):

Although it wouldn’t be traditional for skyr, you can also use fig stem (the leaf stems) latex as rennet (there’s an ancient Italian cheese that does so), and I believe nettles are used in cheese making with some regularity. But yeah, those two carnivorous plants are well known as being good while culturing and definitely have a long history of it. I’ll look for my Icelandic cookery books and see if I can’t find the whey drink you’re looking for, and if not I’ll do some research and see what we can come up with.

Lauren had already learned the fig sap method in Italy (where it’s from), and was also already using cardoons (Spain, if memory serves) as a rennet source. She notes:

The cheesemaker there indicated that it was an acid in the sap rather than an enzyme but it's interesting to know that it's in fact a protease.

That’s pretty exciting. I didn’t realize it was a protease, because I don’t always look into the science of why an ancient method works. That’s why fig sap works!

Eventually, I did make it through as much of my Firefox history as was searchable on the specific topic, which was sent to Lauren largely got a list of links with some brief explanations behind them. I’m keeping largely the same format I used in the email, though these links will be embedded in text this time instead of stand alones:

Legendary Dartmoor has an oral history on the use of sundews specifically.  Other sites with oral histories that I had in my history and definitely used were Word Canoe, Tofino Resort and Marina with a brief mention, Nanna Rognvaldr touches on it, and École-B talks about the rennet properties of sundew, but not with respect to skyr specifically.

Formaggio Kitchen talks about different animal and plant rennets that people may not have used, but doesn’t look at sundew or butterwort. culture cheese mag (no idea why they don’t capitalize) discusses a multitude of vegetable rennets, some of which I’ve never heard of, whereas Fotevikens Museum lists a number of vegetable rennets for skyr and other cheese-making with some notes on which plants they think are best. The museum would also like people to remember that traditional Western cheeses heavily favor animal rennet, even if they’re not going to use animal rennet.

The Scots, being awesomely Scottish, also weigh in here. If you need to be super firm in your Vikingness (Lauren does not, but some of you may wish to), you’d obviously select plants that are present in areas of Scotland the Vikings were trying to colonize. Plantlife has 3 separate options all with plants growing in the Munsary reserve. All three of these options are carnivorous, and 2 of them we have oral histories for regarding Scandinavian usage. At Friends of the Loch Lomand and Trossachs, they really like butterwort and have a fair bit to say about it. So I guess vegetable rennet mattered quite a lot to the Scots as well.

Edible Wild Plants of North America is an eBook on Google Books. If you prefer a physical text, WorldCat is where you check for the library closest to you that has it. If there aren’t any copies available locally, make sure you ask the librarian to assist you with an inter-library loan. For community members who aren’t familiar with the ILL system, you can request that your library borrow a book from another library to loan to you. These books generally cannot be renewed since they belong to a library other than the one you’re using, but you can alays make photocopies of the relevant pages.

Cheese: A Global History also has some information on this, starting on page 72. Lastly, Icelandic Herbs and their Medicinal Uses has a section on butterwort, which begins on page 36.

I hope this helps to get everyone started on learning about various vegetable rennets, but do keep in mind that oral histories are just that and frequently result in fewer hard data you can draw from. This is why most of these links deal with oral histories rather than written ones, since most global cultures were not the types of written record keepers we’ve learned to expect due to the Romans.

Happy cheese making, y’all!