What it is.
To reduce is to cook a liquid uncovered so some of its water turns to steam. What is left is thicker and tastes stronger.
Wine, stock, cream and pan sauces are reduced. Recipes often say reduce by half.
Why it works.
Only the water steams away. Salt, sugar, and the flavor from meat and vegetables stay in the pan. So the same flavor sits in less liquid.
Stock and meat juices have gelatin in them. As the water leaves, the gelatin makes the sauce thick and glossy.
A wide pan reduces faster than a tall pot, because more of the liquid touches the air.
What to look for.
- The level drops. Check it against a mark on the pan.
- Bubbles get bigger and slower as it thickens.
- It coats the back of a spoon, and a finger line through it stays.
Common mistakes.
- It got too salty.
- Salt at the end. Salt gets stronger as the water leaves.
- It is not getting thicker.
- Take the lid off and turn the heat up a little.
- It went too far and turned sticky.
- Stir in a splash of water or stock to loosen it.
