Red Colouring Butter

Ingredients

Equipment Needed

• •Rimmed baking sheet
• •Kitchen scale
• •Heavy-duty food bag and rolling pin or mallet
• •Sturdy spice grinder or large mortar and pestle
• •Fine sieve
• •2-quart (2 L) saucepan and heatproof bowl for the bain-marie
• •Large 3-quart (3 L) bowl
• •Fine-mesh strainer and food-safe muslin
• •Heat-resistant gloves
• •Clean lint-free towel, small board, and weight

Instructions

1. 1

   Empty and dry shells

   Heat the oven to 250°F (120°C). Pick every trace of meat, gill, sac, and soft tissue from the cooked shells; rinse them briefly only if they are gritty, then dry them well. Spread the shells in one layer on a rimmed baking sheet and bake for 60 to 90 minutes, turning them twice, until the thin pieces snap cleanly and the thick pieces feel dry through their joints. Do not let them scorch. Cool completely, then weigh 225 g. If you have less, use precisely the same weight of butter as dried shell.

   The equal weight is calculated after drying. Shells lose moisture unevenly, so weighing them before the oven quietly breaks the formula.
2. 2

   Grind to powder

   Put the brittle shells inside a doubled heavy-duty bag and break them into small pieces with a rolling pin or mallet. Grind them in a sturdy spice grinder in small batches until they resemble fine sand, letting the dust settle before opening the lid. Pass the powder through a fine sieve and regrind the larger pieces. The old mortar demanded an afternoon and strong shoulders; the grinder replaces that labour, but not the fine texture the extraction needs.

3. 3

   Infuse in bain-marie

   Set a heatproof bowl over a saucepan holding 1 inch (2.5 cm) of barely simmering water, making certain the bowl does not touch the water. Add the butter and shell powder. Melt gently, stirring often, then continue over the bain-marie for 40 to 50 minutes. The butter should deepen from gold to clear coral-red, while the shell sediment darkens below it. If the water boils hard or the mixture begins to sizzle, lift the bowl off immediately and lower the heat before continuing. The shells must infuse, never fry.

4. 4

   Strain into iced water

   Combine the cold water and ice in a large bowl. Line a fine-mesh sieve with two layers of clean food-safe muslin and set it directly over the iced water. Pour in the shell butter slowly, then gather the muslin around the hot sediment. Wearing heat-resistant gloves, twist and press the bundle firmly so the red butter passes through while the shell grit stays behind. If butter begins setting inside the cloth, do not discard it. Ça se rattrape: hold the closed bundle over the warm bain-marie just until the fat loosens, then press again over the iced water.

5. 5

   Harden and press

   Leave the bowl undisturbed for 20 to 30 minutes, until the butter has hardened and floated in a coral-red sheet or cluster of pieces. Lift it out with a slotted spoon and blot it thoroughly. Wrap the butter in a clean lint-free towel, place a small board over it, and weight the board with a heavy pan for 10 minutes. Change the towel and repeat if it remains wet; trapped water makes the butter spit in a sauce and shortens its keeping life.

6. 6

   Portion and keep

   Pack the dry butter into a small bowl or shape it into a narrow log in parchment. Chill until firm, then cut it into teaspoon portions if it is destined for the freezer. Add it sparingly to a compatible finished sauce, beginning with 1 teaspoon (5 ml / 5 g) per cup (240 ml / about 240 g) and increasing only until the colour is right. This is concentrated seasoning as well as colour, so let the sauce keep its own character.

Chef Tips

• •Use crustacean shells only: lobster, crayfish, crab, prawn, or shrimp. Oyster, mussel, and clam shells do not yield this butter, and any remaining flesh or gills muddy both its flavour and its keeping.
• •Redness varies naturally. Cooked lobster, crayfish, and prawn shells usually give the clearest coral colour; mixed shells are entirely proper, provided they are clean, brittle-dry, and weighed after drying.
• •Keep the ratio exact. If the grinder gives you 160 g of dry shell powder, use 160 g of butter. C'est la même grammaire, whatever the batch size.
• •Straining removes grit, not the shellfish allergen. Never serve beurre colorant rouge to anyone with a crustacean allergy, and label frozen portions plainly.
• •For a poultry or meat sauce that wants pink colour without a marine note, good mild paprika is the proper separate route. Do not treat the two colourings as interchangeable.

Advance Preparation

• •Clean cooked crustacean shells promptly, seal them well, and freeze them for up to 3 months while you accumulate enough for a batch. Thaw them in the refrigerator and dry them before weighing.
• •The finished butter keeps for up to 5 days refrigerated in an airtight container. For longer storage, freeze teaspoon portions for up to 3 months and take out only what the sauce requires.
• •The shells can be oven-dried and ground a day ahead. Keep the powder tightly covered and cool, then make the butter promptly so its marine aroma remains clean.

Frequently Asked Questions

Nutrition Information

1 serving (about 14g)