No one knows the precise origins of cheese, but the story goes that, millennia ago, a nameless adventurer was making the trek to the next oasis of human civilization when something funny started going on with the milk he or she had brought along for the journey. Stored in a sealed animal stomach, the milk had separated into a kind of watery, savory brine (which today we call whey) and some solid, chewy bits (or curds). Through fortunate happenstance, the complex of enzymes known as rennet, and in particular the enzyme chymosin – found in the stomach linings of ruminants (mammals that chew cud for a living) – had coagulated the milk and created the world’s first cheese.
Historic cheeses throughout the world relied upon animal rennet to separate milk into curds and whey, sowing future confusion among those looking to cut meat out of their diet as to whether or not cheese is vegetarian. (It certainly sounds vegetarian, right? Kind of?)
Well, fear not, intrepid and discerning turophile! For from the lush mountain valleys and arid plains of Portugal comes an elegant, age-old solution to this vexing conundrum: thistle rennet cheeses.
What are you talking about?
Dating at least as far back as the old days of the Roman province of Hispania, the tradition of using plants of the thistle family – think artichokes, or Braveheart – to coagulate milk has produced some of the finest cheeses of the Iberian Peninsula. But why use thistle rennet over animal rennet in the first place?
The short answer: ease of preparation. The kind of high-quality animal rennet necessary for more complex, older cheeses requires trade-offs and technical finagling. Animal rennet is only found in the stomach linings of young ruminants (our magic enzyme, chymosin, helps those baby cows, sheep, and goats digest their mother’s milk), so to make cheese, you’re giving up that animal’s future milk and barbecue potential.
What do you do if you don’t want to sacrifice Ol’ Bess and go through the hassle of cookin’ up animal rennet? Enter the cardoon, once a cultivated mainstay of ancient Roman, Greek, and Persian cuisines. Found in abundance throughout the Mediterranean, cardoons are similar to artichokes, but instead of eating the flower bud you eat the stalk. When those ancient Iberians were figuring out the best way to preserve their excess milk in the form of cheese, they discovered that stamens of this edible plant that grew just about everywhere could coagulate their milk – they realized that they could cut animal rennet completely out of the equation!
The one drawback of using thistle rennet is that its coagulation is not always consistent, but over a couple thousand years Portuguese cheesemakers have learned the ins and outs of the cardoon and refused to back down from their innovative approach. Today, Portugal produces more than a handful of thistle rennet cheeses officially recognized by the European Union.
So tell me about the good stuff!
Cheeses made with thistle rennet have a very distinct, slightly bitter and sour flavor profile. The best thistle rennet cheeses play with that taste to emphasize citrusy notes or to throw in a sour or tangy twist to an otherwise sumptuous foundation. Here are a few standouts with official EU Protected Designation of Origin status to keep an eye out for:
- Serra de Estrela hails from the northern, mountainous region of Portugal. Made in the same way for over 800 years, this sheep’s milk cheese is known for two popular versions: the buttery and spoonable, month-old amanteigada style and the firmer, six-month-old velho style. The thistle rennet gives both a citrusy, earthy flavor alongside a slight sourness.
- The green pastures of central Portugal gave rise to Castelo Branco, a pale, semi-soft, tangy cheese with a spicy/sour finish. The most popular variety is a younger sheep’s milk cheese aged for 45 days, followed by a sheep’s-and-goat’s mixed milk version. Cheesemakers also craft a more mature, 120-day-aged Castelo Branco that uses animal rennet.
- Azeitão is fashioned in the agricultural breadbasket of southern Portugal. This raw sheep’s milk cheese’s barnyard flavor is balanced by savory herbal notes on the one hand and that thistle-rennet sour-bitter taste on the other. Textures range from smooth velvet when ripe to a drier, stolid firmness when aged.