Kitchen terms · International
Reduction
Boiling down a liquid to evaporate water so that a sauce, stock or wine thickens and gains flavour.
At a glance
- Origin
- Fr. réduire, culinary sense “to make evaporate” a syrup or sauce (TLFi).
- Production
- The liquid boils; water evaporates while flavour compounds remain.
- Use
- Sauces, glace de viande, wine and juices in braising.
- Substitutes
- Thickening with roux, starch or egg yolk adds a thickener; reduction only removes water.
To reduce means letting a liquid evaporate until it thickens and intensifies. The Trésor de la langue française gives the culinary sense of réduire as “to make evaporate”, with syrup and sauce as examples. Unlike thickening with roux or egg yolk, nothing is added here; only water is lost.
The extreme case is glace de viande: Escoffier makes it by reducing brown stock, moving it into ever smaller stewpans as it boils and straining it at each change. It is ready when it evenly coats a spoon, and the last stage must proceed slowly over a moderate fire. When braising, Escoffier likewise reduces the wine of the marinade to the consistency of syrup before adding stock.