Max Graham, Founder
The cardo, or cardoon flower (Cynara cardunculus), is one of the most important ingredients in traditional Portuguese cheesemaking. This wild purple thistle, used as a natural coagulant for centuries, is responsible for the famously creamy, spoonable textures and distinctive, earthy flavours found in Portugal’s most celebrated DOP cheeses. Long before commercial rennet existed, shepherds in the Centro de Portugal used the cardoon flower to curdle raw sheep’s milk. Today, cardoon-based coagulation remains protected within Portugal’s dairy heritage and continues to define cheeses such as the unparalleled Queijo Serra da Estrela DOP and the lush Azeitão DOP.
The cardoon flower is harvested in midsummer, when its purple bloom dries naturally on the plant. The dried stamens are soaked and used as a potent plant-based coagulant, often referred to as vegetable rennet. Using cardo gives these Portuguese cheeses their signature, sought-after characteristics: Soft, creamy or spoonable textures, delicate floral aromas and a subtle, earthy bitterness that balances the richness. This method is unique to Portugal and central Spain, but nowhere is it more culturally significant than in the Serra da Estrela and Arrábida regions.
In the mountains of Centro de Portugal, cheesemakers have relied on cardoon for generations to create Serra da Estrela DOP, the country’s most iconic cheese. Made from the milk of Bordaleira da Serra da Estrela and Churra Mondegueira sheep, it develops the rich, custard-like centre that only cardoon coagulation can produce, a true taste of tradition.
The town of Seia, home to the renowned Museu do Queijo, sits at the heart of this cheesemaking region. It also produces its own Seia Amanteigado, a luscious, spoonable raw sheep’s cheese made in the same spirit as Serra da Estrela but not part of the DOP designation. Its texture and flavour pay homage to the area’s heritage while offering a distinct expression of local milk and craft.
Discover Seia Amanteigado on our cheese sellection at Bar Douro.
Just outside Lisbon, in the Arrábida foothills, Azeitão DOP offers a smaller but equally characterful expression of cardoon-coagulated cheese. Firmer than Serra da Estrela but still lush and creamy, Azeitão reflects its Atlantic climate with bright, tangy notes and an unmistakable vegetal character from the cardo.
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