Sometimes when I’m asked what the secret is to a dish I’ve made, the answer is a specific little trick I’ve picked up from my mother or a cookbook. But more often than not, the big secret is not a secret at all. It’s lemon.
Adding lemon juice or zest to a dish, sweet or savory, changes its whole flavor profile. Suddenly, a pretty good tomato sauce is brimming with complexity, a blackberry pie tastes like it’s packed with a thousand perfect berries and all of summer, and braised broccolini isn’t just a convenient side dish—it’s the best part of the meal. The citrus fruit contributes that glorious savor you can’t quite put your finger on. Lemons are as crucial a flavor-enhancer as salt. But while salt is a mainstay in even the worst stocked pantries, lemons are often tragically overlooked.
Actually a type of berry called hesperidium, the lemon was probably first used in food and drink more than 2,000 years ago in northwestern India. According to Lemons: Growing, Cooking, Crafting, the Ancient Romans first introduced the fruit to Europe when they began trading with India around 100 A.D. However, Romans didn’t take to the lemons’ sour taste and used them as decoration rather than food (as do many contemporary Americans I know). Lemons have since spread from India and Rome to the Middle East, Africa, China, and the Americas, and the lemon remains one of the most widely used ingredients from continent to continent—and yet few people take full advantage of their seasoning potential.
On your tongue, salt and lemons work a similar kind of magic. Biochemically speaking, salty and sour taste receptors are relatively simple compared with their sweet, bitter, and umami counterparts: Tasting salty and sour flavors depends solely on the detection of ions—sodium for salt, hydrogen for sour—whereas tasting other flavors depends on more complicated receptors. Acidity, like saltiness, also leads to an increase in salivation—both flavors literally make food more mouth-watering. Since tasting depends on saliva’s power as a solvent, the presence of saliva on your tongue is necessary for your taste buds, and therefore your brain, to perceive flavor. The upshot is that a squeeze of lemon is as good as a dash of salt in bringing out the flavor of just about any food.
Besides making your mouth water, acidity cuts greasiness and heaviness and gives food a fresh, clean taste. Lemon juice can also change a food’s texture to fit a variety of needs, as when macerating berries, tenderizing meat, and “cooking” ceviche. Lemon juice contains citric acid, which helps break down fats, carbohydrates, and protein.
But lemons aren’t just useful for their juice—the zest contains lemon oil, which is where you’ll find the most flavor-bang for your lemon-buck hiding. This is especially handy in instances where you want to add flavor, but not additional liquid, as with pie crusts. And, unlike unsubtle salt, too much of which will strangle the flavors in your food, lemon juice and zest play nicely with bitterness, sweetness, piquance, and umami, helping them reach their full potential.
The lazy side of some of us is no doubt wondering: Why can’t I just use vinegar to add acidity to my food? Vinegar does indeed have the advantage of a much longer shelf life than lemons, though not an infinite one. (If you were wearing gauchos when you bought your most recent bottle, it’s been in your pantry too long.) But many vinegars are also concocted to have their own flavors, whether rich and sweet (think balsamic) or bold and fruity (as with apple cider or raspberry vinegar), which can be overbearing or clash with other flavors. (Alternatively, some vinegars, such as champagne vinegar, are extremely mild and delicate and may disappear into a dish instead of clarifying and bolstering it.) Darker vinegars can also turn the color of a dish unappealingly muddy. Moreover, the delicious ones are expensive, and the cheap ones may ruin hours of work with one fell glug. Lemons, by comparison, are inexpensive, easy to find, consistent in quality, and hard to use incorrectly.
So start letting lemons make your life better. Picking good lemons isn’t hard: They should be bright yellow in color, firm to the touch, smooth, and heavier than you might expect considering their size. They should also be lemon-shaped. (Seriously. The closer it looks to the Platonic ideal of a lemon, the more likely it is to be perfectly juicy.) If you pick right, they’ll last for several days at room temperature or even longer in the crisper drawer of a refrigerator. (Chilling lemons makes them harder to juice and zest, but you can roll one back and forth with your palm on the counter, as you would a rolling pin, or pop it into the microwave for a few seconds to release the juice and soften the rind, making it easier to squeeze.)
And how should you use that juice and zest once you’ve obtained it? Here are a few ideas: Squeezed into soups, sauces, and drinks. Tossed with salads, vegetables, and pasta. Rubbed onto pork, chicken, and fish. Baked into cakes, muffins, and snacks. And added to anything and everything containing mayonnaise.
For most dishes—with the obvious exception of baked goods, lemon-marinated meats and vegetables, and the like—a squeeze of lemon should be added right before cooking finishes. Cooking lemon for a long period of time will concentrate the flavor and can make it bitter. It can also dull the color of vegetables if added too soon, whereas it will brighten color if added at the end (so long as you haven’t killed it with overcooking). If you do go overboard and your food tastes too sour, a tiny bit of sugar (just a pinch at a time!) should save the day, even in savory dishes.
So go out and buy a few; even if you don’t use all of them, you’ll only be out a few bucks. And though you can use extras to make lemonade, I like to improve on the proverb by making limoncello.