Garnishing acids, on the other hand, are used to finish a dish. While no amount of salt at the table will make up for underseasoning food from within, a hit of acid at the very last second often improves food, which is why garnishing acids are so important. As the volatile aromatic molecules disperse over time, the flavor of fresh citrus juice will transform, losing some of its brightness—so freshly squeezed juice is best. The application of heat will change the flavors of both citrus juice and vinegar, dulling the former and mellowing the latter, so add them just before serving when you want their full flavor impact.
You can incorporate different garnishing acids into a single dish to increase flavor. Balsamic vinegar isn’t always acidic enough to dress a salad on its own, so spike it with red wine vinegar. Or layer vinegar with citrus juice, which is brighter: make Citrus Vinaigrette with white wine vinegar and blood orange juice to drizzle over an Avocado Salad . The strong acidity of the vinegar will balance the richness of the avocado, while the vivid orange juice will round out its flavor.
When you can, use the same kind of acid for cooking and garnishing—spoon tomato salsa, for example, atop pork braised with tomatoes; finish a risotto with a fresh splash of wine from the same bottle used earlier to deglaze the pan. This kind of layering offers multiple tastes of the same ingredient.
And then there are times when a single form of acid isn’t enough to accomplish its task. Feta cheese, tomato, olives, and red wine vinegar offer four distinct forms of acid in a Greek salad. To bring out a chorus of bright, happy notes, serve that pork I mentioned above with all kinds of acidic condiments, including queso fresco , sour cream, and a Bright Cabbage Slaw tossed with vinegar and lime juice.
And think back to that Caesar salad, where Parmesan and Worcestershire sauce—sources of acid—both lend the dressing tang as well as salt and umami.
Balance the creamy, salty dressing with wine vinegar and lemon juice. Tinker with all four sources of acid as you taste and adjust, little by little, until it’s perfect.
Make Pasta alle Vongole to practice layering acids. I like to make clam pasta with two varieties of clams—littlenecks, which lend an intense brininess to the dish, and cherrystones or Manilas, which are small enough to toss in whole and eat directly out of the shell along with the pasta. First, set a pot of water to boil and season it with salt. Rinse the clams and dice an onion, saving the root ends.
Heat a large frying pan over medium heat and splash in some olive oil. Add the root ends of the onion, a few parsley sprigs, and as many littlenecks as will fit in a single layer, then pour in enough wine to cover the bottom of the pan. Turn the heat up and cover the pan. Let the clams steam until they open, which should take two or three minutes. Use tongs to pull the clams from the pan into a bowl as they open. Some of the stragglers might need a little encouragement, so tap them with your tongs if they’re taking too long.
Cook the rest of the littlenecks in this way, adding more wine if needed to cover the bottom of the pan. When you’ve removed all of the clams from the pan, strain the liquid through a fine-mesh strainer or cheesecloth; this clam- cooking liquid is priceless. Plus, it’s now the dish’s main source of acid. When the clams are cool enough to handle, pluck them from their shells and run a knife through them, then return them to the clam-cooking liquid.
Rinse out the frying pan, then set it over medium heat. Add just enough oil to coat the pan, and when it shimmers, add the diced onion and a pinch of salt.
Stirring from time to time, cook the onion until it’s tender. It’s fine if it picks up a little color, but don’t let it burn; add a splash of water if you need to. Then taste
the pasta water, make sure it’s as salty as the sea, and cook the linguine until it’s not quite al dente, about 6 or 7 minutes.
Add a clove or two of sliced garlic and some red pepper flakes to the onion and allow it to bloom , or sizzle gently without taking on any color, then add the cherrystones or Manilas and crank up the heat to high. Add a healthy splash of the clam-cooking liquid and cover the pan. As soon as the little clams pop open, use a slotted spoon to add the chopped littlenecks into the pan. Cook all of the clams together for about a minute, and then taste and adjust the acid with more white wine or a squeeze of fresh lemon juice.
When the pasta is not yet al dente, drain it, reserving a cup of the pasta water.
Add the noodles directly to the pan with the clams. Continue to cook the pasta, swirling the pan, until the noodles are cooked al dente. This way, the pasta will absorb all the briny flavor of the clam liquid as it finishes cooking. Taste again and adjust for salt, acid, and spiciness. If the noodles seem dry, add some of the reserved pasta water.
Now begins the magic of garnishing (and fat). Intensify the creaminess and flavor of the dish by tossing in a knob of butter. Next, add chopped parsley and some freshly grated Parmesan. Some might balk at adding cheese to a seafood pasta, but I learned this trick from the chef at a beloved seafood restaurant in Tuscany, where this pasta was so delicious it helped me overcome my lifelong aversion to clams. The salt, fat, acid, and umami offered by the cheese makes this pasta unforgettable. For a final touch of acid and crunch, sprinkle the dish with toasted sourdough bread crumbs. They’ll be crisp when you first dig in, but as they mingle with the pasta, the bread crumbs will absorb the clam juice, becoming little flavor bombs exploding with each bite.