How do you make a balsamic reduction?

You should put balsamic vinegar in a saucepan using, if possible, a thick-bottomed one, to avoid the vinegar from burning or caramelizing. Place on the stove on the smallest heater you have, and let it boil softly until you reduce it to about one quarter of the starting volume. By that point, your reduction should have a syrupy texture. It will get much thicker when it cools down. If it got too thick, you can add a little water and reheat it to allow it to properly mix, then let it cool down again.
If you're in a hurry, you can add a little sugar to the balsamic vinegar before starting the reduction process, or even thicken it with a slurry made from rice flour, but the results won't be as good as with the classical method.

First answer by Julienlesaux. Last edit by Julienlesaux. Contributor trust: 4 [recommend contributor]. Question popularity: 1 [recommend question]