There are other ways to coagulate cheese that don’t involve animal rennet. Plants like thistles, nettles, and figs all contain enzymes that act similarly to the chymosin and rennin that is extracted from the 4th stomach of calves, lambs, and goat kids.
Madeline Q. had a fantastic idea that we could use some of the surplus milk that we can’t drink or make cheese with (since we gave some of the animals a chemical wormer) to experiment on. Lyndal had never played around with how many stamens to use for coagulation so it was a brilliant way of doing a purposeful experiment with the unusable milk.
Jazz and I sitting by the cardoon plants
Cardoon Stamens
To use the plant for rennet, you extract the purple stamens from the blooming heads. To coagulate the milk properly, it must reach a point called flocculation fairly quickly, but not too fast. Flocculation means that the molecules of the milk are starting to bond together, and it is measured in the time that it takes for the milk to become coagulated. Flocculation is tested (in the simple way) by putting a plastic lid on top of the thickening milk and giving it a spin. Before you add the rennet, and in the first few minutes, the lid spins freely without resistance. When the milk is flocculated, the lid will be hard to spin and turn only sluggishly. Typically once the milk has reached the flocculation point, you add the equivalent amount of time to wait for the milk to become curd. Sometimes it needs to be doubled or tripled depending on the firmness of the desired cheese.
We had absolutely no idea how many stamens to start with so our attempts were a shot in the dark. We had 2.5 liters of milk from the morning from the animals we dewormed, so we decided to split the milk into five 500ml samples. We then collected stamens and measured them out into samples of .5 grams, 1 gram, 1.5 grams, 2 grams, and 2.5 grams. Each jar received one of these amounts, and then we added 500 mls of milk to each one.
The experiment design and process was primarily designed and carried out by Maddy, who was very excited about her idea. I had fun being an active watcher and learned a lot just from observing.
After waiting for about 15 minutes, nothing was happening. Lyndal told us the milk definitely should’ve reached flocculation by now so we clearly didn’t add nearly enough stamens for proper coagulation. There weren’t too many stamens left on the plants, but we collected the remaining ones which gave us an additional 5 grams. We threw the 5 grams in with the sample that had 2.5 in it already. Alas, the milk was thick and flocculated 6 minutes later, which is a much more appropriate time.
