Reduction is a technique that is used to thicken and enhance the flavor of a liquid mixture such as soups, stocks, sauces, and wines. It is achieved by simmering or boiling the liquid – which causes it to evaporate – until the desired volume is reached.

This should be done without a lid, as the vapor needs to be allowed to escape into the air. If the lid were to be left on, the water vapor coming from the mixture would collect on the under side of the lid and simply fall back into the mixture and it would never reduce.

Something else to consider is that different components of the liquid mixture will begin to evaporate at slightly different temperatures. Reducing can actually be considered a form of distillation, as the goal is to get rid of the components with the lowest evaporation points, while leaving those which have the highest boiling point.

Reduction is a great way of condensing and concentrating flavors, but make sure you don’t over-reduce. If you remove too much of the liquid from the sauce, you’ll likely end up with a sticky, burnt mess on the bottom of your sauce pan.

Simmering (as opposed to boiling) is almost always the preferred method of reduction. By simmering the liquid mixture for long periods of time, (anywhere from 1 – 10 hours or more) the flavors will have ample time to fully develop. In addition, any impurities will collect at the top and can be removed with a large spoon or baster.

Personally, reduction is one of my favorite techniques. And to be honest, it’s kind of hard to screw anything up, because if you feel that you might have reduced your mixture too much, you can always just add more water. It’s a rather slow process, so you won’t be rushed.

Lastly, if you have anything such as meat, veggies, or potatoes in your sauce, keep in mind that the longer you keep reducing the sauce, the more tender those items will become. If you think they might end up getting too soft, you should go ahead and remove them from the sauce.