Most people are familiar with the fact that vinegar adds sourness to a dish, in varying degrees from light acidity to puckering acid. However, vinegar can also be used in lieu of salt when seasoning the final touches to sauces, soups, and stews.
I may be nuts for vinegar, but I'm not crazy; adding a touch of vinegar and a good stir right before serving your food ups the complexity of its flavors, much in the same way salt does. Its sharp profile brightens and sharpens the flavor of a sauce—much in the same way a squeezed lemon wedge adds a burst of acidity to a protein such as chicken or fish.
According to Cook's Illustrated, simply add a dash of vinegar (less than 1/8th of a teaspoon) to your dish and stir before adding any additional salt. The extra kick of vinegar will tone down any bitterness that would normally be cancelled out with salt, and will add a subtle but bright complexity to the rest of the flavors in your dish.
As for what vinegar to use, Cook's Illustrated recommends a vinegar whose ingredients match the initial ingredients of the recipe you're using; for example, any sauce that uses red wine would be best paired with red wine vinegar, while any dishes that include slightly sweeter flavors would go well with apple cider vinegar. It pays to have a wide variety of vinegars in your arsenal, but a milder white wine vinegar would work well as an all-purpose seasoning.
Adding complexity and brightness to food is all well and good, but it's important to note that using vinegar as a final seasoning also discourages the overuse of salt, which is especially important for folks suffering from hypertension, or high blood pressure. Low-sodium diets are often a little lackluster; this handy flavor hack will wake those taste buds up without compromising blood pressure levels.
As someone who has a family history of hypertension, it's important for me to be cognizant of my sodium intake. Thanks to vinegar, I don't have to do so with bland, unappetizing food.
So, the next time you taste a dish right before serving it to friends and family and feel it's missing that certain je ne sais quoi, try adding a splash of vinegar to your food before you pick up the salt shaker. You'll use less salt, bump up the flavor, and have your friends scrambling to figure out how you managed to make food so rich in complexity!