Shellfish Stock

Heat the oil in a wide, heavy stockpot over high heat until shimmering and just beginning to smoke. Add the shrimp shells and heads in a single layer — do not crowd. Roast, stirring occasionally, for 5–7 minutes until the shells have turned deep salmon-pink to coral-orange and the heads have caramelised around the edges. The kitchen should smell intensely of the sea and toasted crustacean. This Maillard browning is what builds the stock's colour and depth.

Reduce heat to medium. Add carrot, celery, and onion directly to the pot with the shells. Cook, stirring occasionally, for 5–6 minutes until the onion is translucent and the carrots have softened at the edges. The vegetables are not meant to brown — they add sweetness and body, not colour. If they begin to caramelise, add a splash of water.

Add the tomato paste directly to the pot and stir for 1–2 minutes until it coats everything and turns slightly darker, jammy-red. Pour in the white wine — it will hiss and steam violently. Scrape up every trace of fond from the pot bottom using a wooden spoon. Allow the wine to reduce by half, about 3 minutes, so the alcohol cooks off and the liquid becomes syrupy and fragrant.

Add the cold water, bay leaves, thyme, and peppercorns. Bring to a gentle simmer over medium heat — never a hard boil, which makes shellfish stock bitter and cloudy. Maintain at a lazy simmer with just a few bubbles breaking the surface. Cook for exactly 20–25 minutes. Shellfish stock extracts quickly and over-extraction turns it bitter; unlike chicken stock, more time is not better.

Remove from heat and rest for 5 minutes. Set a fine-mesh strainer over a large bowl and ladle the stock through — do not press the solids, which would squeeze bitter compounds out of the shells. Discard all solids. The finished stock should be clear enough to see the bottom of the bowl, with a delicate coral-pink hue. Use immediately for bisque or sauce, or refrigerate for up to 2 days. It will not gel like meat stock — it is thin and aromatic by nature.