Reducing a sauce simply means simmering it over heat to evaporate water and concentrate the remaining flavours. It is one of the most fundamental techniques in cooking and is used for everything from pasta sauces to wine reductions to glazes.
Why Reduce?
Reduction achieves two goals simultaneously:
- Thickening: As water evaporates, the sauce becomes more viscous.
- Flavour concentration: Flavour compounds remain as water leaves, intensifying the taste.
How to Reduce a Sauce
- Place the sauce in a wide, heavy-bottomed pan. Wider = more surface area = faster evaporation.
- Bring to a gentle boil, then reduce to a steady simmer.
- Stir occasionally to prevent sticking at the bottom.
- Keep the pan uncovered — covering traps steam and prevents evaporation.
- Check progress by pulling a spoon through the sauce. A properly reduced sauce coats the back of a spoon and leaves a clear line when you drag your finger through it.
Reduction Fractions
Recipes often specify a target: "reduce by half" means evaporate 50% of the liquid. "Reduce by two-thirds" leaves one-third of the original volume.
An easy way to track this: place a spoon in the sauce before reducing and mark the level. Reduce until the level hits your target.
Common Mistakes
- High heat: Reduces too fast, scorches the bottom, and causes bitter flavours.
- Small pan: Less surface area = slower reduction.
- Forgetting to taste: Reduction concentrates salt, so a sauce that tasted well-seasoned before reducing may taste too salty after. Correct seasoning at the end.
When to Season
Season after reducing, not before. Reducing concentrates salt along with flavours. Always taste at the end and adjust.