Gastrique — Caramelised Sugar and Vinegar Reduction

Ingredients

• 100 g white sugar
• 2 tbsp water
• 100 ml vinegar, sherry vinegar for duck; red wine vinegar for red meat; cider vinegar for pork; white wine vinegar for neutral applications

Method

1. 1
   Place 100 g white sugar and 2 tablespoons of water in a heavy-bottomed stainless-steel or copper saucepan. Heat over a medium flame without stirring. Stirring introduces air bubbles and promotes crystallisation; leave the pan undisturbed. The sugar is ready to proceed when it is fully dissolved and the syrup is clear.
2. 2
   Continue heating, still without stirring, until the caramel reaches medium amber — the colour of dark honey, smelling of toffee, just beginning to release wisps of smoke. This is 165 °C. This is where the dish lives or dies: below this point the caramel lacks depth; above 180 °C bitter, acrid compounds form and the gastrique is unusable.
3. 3
   Stand back and add 100 ml of chosen vinegar in a single pour. The caramel will erupt violently — steam, spatter, and the sugar may seize into a hard mass. This is expected. Switch to stirring and continue heating; the seized sugar re-dissolves within 2–3 minutes. The pan is ready to proceed when the liquid is fully smooth and uniform.
4. 4
   Reduce over medium heat, stirring occasionally, until the gastrique is syrupy and coats a spoon thinly, dripping in slow, viscous drops. At this point roughly 50 ml will remain. Remove from the heat.