Court bouillon

Court bouillon, French for "short broth", is a quickly made, lightly acidic liquid used for poaching delicate food, especially fish and shellfish. It is water simmered with wine or vinegar, onion, carrot, celery, herbs and peppercorns. Unlike a stock, it is made to cook in, not to keep as a sauce base.

How to do it

1. In a wide pan, combine 1.5 liters (6 cups) water, 250 ml (1 cup) dry white wine, or 2 to 3 tablespoons white wine vinegar, 1 sliced onion, 1 sliced carrot, 1 celery stalk, a bouquet garni, 6 peppercorns and 1 tablespoon salt.
2. Bring to a boil, then simmer for 20 to 30 minutes.
3. Strain it if you want a clean liquid, or leave the vegetables in.
4. Let it cool a little before adding fish. Poach at a bare simmer, with the liquid just trembling.

Why it works

The acid helps fish flesh stay white and firm, and the aromatics flavor the outside of the food as it cooks. Gentle heat keeps fish moist, while a hard boil breaks up the flesh.

How to use it

Poach a whole salmon, fillets of cod or halibut, shrimp, lobster or mussels in it. For a whole fish, start it in cool court bouillon and bring it up slowly so the outside does not overcook before the center is done. For fillets and shellfish, lower them into liquid that is already hot. Fish is done when it flakes and reaches 63°C (145°F) in the thickest part.

Common mistakes

• Boiling the fish, which makes it dry and ragged.
• Skimping on salt and acid, which gives bland fish.
• Using too small a pan, so the fish is not fully covered.

In recipes

Recipes may call it a "poaching liquid" or "aromatic broth". Some versions use milk for smoked fish, or plain salted water with lemon and herbs. After poaching, you can strain and reduce it for a light sauce, though it is thinner than a fumet.