How to blanch cardoons?

The Cardoon (Cynara cardunculus) is a biennial vegetable plant cultivated for the midribs of its foliage. This vegetable is also decorative thanks to its deeply cut, grey-blue or silvery leaves and its flowering which produces large indigo to violet thistles. To be eaten, the cardoon midrib or stalk must first be blanched. It can then be prepared cooked in gratins, purées, juices, with pith or as an accompaniment to meats. Cardoon stalks are rich in fibre, mineral salts and carbohydrates.

The Cardoon or Cynara cardunculus

Why blanch cardoon stalks or midribs?

By depriving certain parts of the plant of light, in this case the midribs, they can no longer carry out photosynthesis. The chlorophyll therefore disappears from these parts, which has the effect, in vegetable garden cardoons, of making the stalks more tender.

Blanched cardoon midribs on a market stall

When to blanch cardoons?

This operation is carried out in September, approximately 3 to 5 weeks before harvest. Harvesting can continue until the first frosts. Frost blackens the midribs, making them inedible. However, the cardoon can be lifted from the soil and the plant replanted in sand in a dark, well-ventilated place (a well-ventilated cellar). This way, the midribs or stalks can continue to be consumed.

How to blanch cardoons?

Simply prevent the sun's rays from reaching the petioles of the leaves (the stalks or midribs). These, deprived of light, will then whiten over the weeks.

1. Remove damaged stems and leaves;
2. Clean the stalks to be blanched a little: just by hand, removing dead leaves or other plant debris that may have accumulated in the centre of the clump;
3. Tie the leaves together using good quality string;
4. Create a protective sleeve either with straw (traditional method) tied around the base, or, more simply, using cardboard that you attach with a rope;
5. Complete the operation by earthing up with a hoe, that is, by mounding soil around the base of the cardoon.

Here the cardoons have been protected with heather thatch