At its core, reducing is simply simmering a liquid to evaporate water. That’s it. No complicated chemistry, just heat and time. As the water turns to steam, the remaining flavors become more concentrated, thicker, and intensely rich. Think of it as the edible version of turning up the volume on a good song.
This isn’t a new trick, either. Ancient Roman cooks used reduction to make garum—a fermented fish sauce that was the ketchup of the empire. The technique has survived millennia because it works beautifully and requires almost no effort. If you can boil water, you can reduce.