There was a time when my description of sauce perfection would never have featured the word sticky. But like any good sauce, when a well-made gastrique serves its plate honorably—moistening our bites, brightening flavor and kicking up color, often to a beautiful berry or citrus hue—what's not to love?
In plain terms, a gastrique is a sweet-and-sour sauce at its simplest. You caramelize sugar (or sometimes honey), combine it with equal parts vinegar, and reduce it slightly to make a tart, slightly thickened syrup.
Let it be said that some gastriques might not be the kind of sauce you want to lick straight off the spoon. (Well, maybe once or twice.) Although caramelizing the sugar and cooking down the vinegar will take the straightforward sweetness and tartness down a notch to a more savory level, gastriques can pack quite a punch. Depending on the flavorings used, they can go with everything from delicate fish and desserts to more robust foods like meat in combination with richer, fattier elements like a pan sauce.
Flavoring a Gastrique
Since the flavor base comes from the simple combination of the sugar and vinegar, your first bet for customizing the flavor is to choose your vinegar. Seem like small potatoes? Think of the spicy, sharp flavor of cider vinegar, versus the fruity raspberry flavor of a red wine version, then imagine trying to incorporate one into your dish. The list goes on: Balsamic, sherry, white wine and champagne will each enhance certain other foods and flavors.
As you'll see in the slideshow, your second option for flavor tweakage is to experiment with added ingredients once the gastrique base has finished cooking. At this final stage, you can add fresh fruit or berries, a dash of juice like tomato or orange, alcohol, citrus peel, herbs, spices or chiles. Heat them through, or do a final round of reducing if needed, and serve.
What to Serve It With
Gastriques are pretty but plucky. Usually a little will go a fairly long way, so try not to get carried away with the plating. Play with flavor combinations based on the protein you're serving. A rich red cherry or blackberry gastrique, for example, can stand up to fattier red meats like duck or beef, while a more delicate mango or apple may pair better with lighter pork or poultry. And citrus or herb versions are great options for seafood dishes.
Gastriques can also be combined with other sauces, simply providing a tangy element to a larger flavor profile. One of the most seductive instances I've heard of is using a tomato version to perfectly acidify pan drippings from a roasted chicken. And, I have yet to see this in action, but mixologists have started to incorporate gastriques into their cocktails for flavor and color, too.
I still have some berry gastrique in my fridge (luckily, they keep for weeks), and am fully planning to test its snack capacity. Doesn't it sound divine spread with buttery, soft cheese on crusty bread for breakfast or a quick snack? Indeed, it does.