Shrimp Stock

Method

1. Use shells and heads saved from shrimp prepared that day, or frozen immediately after peeling and thawed safely in the refrigerator. Do not use discarded shells from diners’ plates or seafood left warm for hours. Rinse away visible grit briefly and drain well.
2. Heat oil in a 3 litre pot over medium heat. Add shells and heads and stir for 4–5 minutes until they change colour and smell cooked, not burnt. Press heads lightly with the back of a spoon without spraying liquid.
3. Add onion, carrot, celery and garlic and stir for 2 minutes. Add bay leaf, peppercorns and the cold water. Bring slowly to a gentle simmer while skimming any foam from the surface.
4. Simmer uncovered for 20–25 minutes. Keep bubbles gentle and do not extend to an all-afternoon boil; a short extraction gives a cleaner stock for delicate dishes. Add water only if evaporation would reduce it well below 1 litre.
5. Set a fine sieve over a clean heatproof vessel and line it with a clean damp muslin cloth if available. Strain in manageable portions. Do not force brittle shell pieces through the sieve or squeeze the cloth with bare hands while hot.
6. Use immediately in a fully cooked dish, or divide into shallow containers and cool rapidly in an ice-water bath, stirring with a clean spoon. Refrigerate within 2 hours, or within 1 hour in a room above 32°C. Do not leave the stockpot out overnight to cool.
7. Label as unsalted shrimp stock with the date and shellfish allergen. Keep at 4°C or colder and use within 2 days, or freeze promptly in measured portions for up to 2 months for quality. Reheat the portion being used to a boil and discard shells and spent vegetables.