A whole trout, poached alive in a vinegar-spiked court-bouillon until its skin turns a deep opaline blue. Truite au bleu is a rare and noble dish from French river cuisine, demanding freshness, restraint, and perfect timing.
FR / EN
Truite au bleu / Blue Trout
Regional Style
Alsace, Franche-Comté / Classic River Cuisine
Servings
Serves Two to Four
Ingredients
- 1 live freshwater trout (approx. 500–600 g), ideally just caught
- 2 tablespoons white wine vinegar
- 1 liter of water
- 1 small onion, halved
- 1 carrot, sliced
- 1 bouquet garni (parsley, thyme, bay leaf)
- Salt
- 6–8 black peppercorns
- For serving
- Melted butter or Sauce Hollandaise
- Boiled potatoes or buttered greens
- Chopped parsley or lemon slices (optional)
Preparation Method
Ensure the trout is alive until just before cooking. Do not gut or descale it in advance. The freshness and integrity of the mucous membrane are essential for the blue coloration.
Bring the water, vinegar, onion, carrot, herbs, salt, and pepper to a gentle boil. This is your court-bouillon. Simmer for 15 minutes, then reduce the heat to just below boiling.
Quickly dispatch the trout and clean it, gutting without damaging the skin. Rinse briefly under cold water and immediately plunge it into the just-simmering court-bouillon.
Poach gently for 10 to 12 minutes, depending on the size, until the skin turns bluish and the fish is just cooked through. Do not allow the liquid to boil. Carefully remove with a fish spatula and drain briefly.
Serving Suggestions & Garnishes
Serve immediately on a warmed platter. Accompanied by boiled new potatoes, melted butter, or Sauce Hollandaise. A light sprinkle of chopped parsley or a lemon slice may be added. A Riesling or dry Alsatian white is the traditional pairing.
Tips, Tricks, or Variations
Use only live trout caught from clean waters, such as river-fed tanks. Do not rinse with acidic or hot water, as this will cause the mucous layer to be lost and prevent the skin from turning blue. Do not add vinegar after poaching—the fish must be immersed while still freshly rinsed. The court-bouillon should be gently acidic, not sharp.
Historical & Cultural Context
Truite au bleu is one of the oldest surviving dishes of Central European river cuisine, found in Alsace, Lorraine, the Jura, and southern Germany as early as the 17th century. The blue color comes from a natural reaction between the acidity of the vinegar and the mucous membrane of an ultra-fresh trout—a subtle display of freshness and technique.
By the 19th century, the dish was prized in thermal spas, river lodges, and bourgeois homes with access to live fish tanks. It symbolized purity, seasonality, and connection to place. It is a ceremonial dish, not for everyday eating, but for moments when ingredients and attention align.
Today, the dish has nearly vanished from domestic tables due to the difficulty of sourcing live trout and the exacting nature of the process. But where it survives—in river restaurants of Alsace or Savoy—it remains a quietly magical experience.
