If the pucker factor of lemon juice, vinegar, or Greek yogurt just makes you wince, or if the prickly sensation of bitterness on the sides and back of your tongue makes your nose scrunch and your taste buds recoil, you’re far from alone. Turns out that while we’re genetically predisposed to love sweet foods, nature probably warned humans off bitter and sour tastes back in the hunter-gatherer era, when the bitterness of a berry, leaf, or shrub may have signaled its unfitness for human consumption.
So if sour and bitter aren’t your thing, you may just have a finely honed self-preservation instinct buried deep in your DNA. Which is fine, but if you’re unable to enjoy these two endlessly fascinating, complex, and multidimensional tastes—as many of us find ourselves able to do the older we get—you’re missing out. And given their increasing popularity, particularly among adventurous Millennials and Gen Z consumers, you’re probably finding them harder to avoid, too.
To clarify: Sour foods such as limes, pickled vegetables, buttermilk, and malt vinegar get their distinctive tangy quality from natural acids, whereas the bitterness of black teas, dark chocolate, arugula, Brussels sprouts, fennel, and Campari liqueur derives from amino acids, peptides, and organic or inorganic salts. Both flavors can be described as tart, sharp, pungent, tannic, astringent, caustic, or acrid, but their sharpness has become a selling point rather than a shortcoming.
What accounts for the rise in the fortunes of bitter and sour? I attribute it in part to the omnipresence of coffee, tea, bitter vegetables, heavily hopped craft beers, and clever artisan cocktails, among other trends. But some of the shift from sweet to sour and bitter also may be health-related. Consumers working to limit their sugar intake are finding that sour and bitter flavors offer some compensation for the loss of sweetness, which makes it easier to swear off the cloying stuff.
So what are the implications for quick-serve chains interested in leveraging the power of sour or bitter’s new glitter? I see a few possible angles.
Introduce sour/bitter notes to foods in nuanced ways
With sour and bitter, the idea isn’t to assault or overrun the consumer’s palate; what you want is to pique it. And there are several subtle but satisfying ways to go about this. I recommend, for instance, using tea as a flavor component to bring bitter notes to different dishes. For meats and vegetables, you can create delicious and highly distinctive seasonings from tea leaves that have been ground and blended with various other herbs and spices—say, Earl Grey with garlic and ginger.
Using fermented or pickled foods in place of regular vegetables is another option for introducing a little pucker to existing items. Substituting pickled red onions or carrots for the standard varieties in tacos or tostadas, for example, can give these products a more interesting and complex flavor profile. Then there are bitter greens such as kale, Swiss chard, chicory, and either beet, mustard, or dandelion greens, all of which can go a long way toward enlivening a salad or a pesto sauce and boosting any product’s nutritional value.
Yogurt, meanwhile, has been underexploited as an addition to conventional recipes. Adding it to pizza, fried chicken or fish batter, condiments, or ground beef and vegetables lends a pleasing tartness to standard-issue products and imparts a more satisfying mouthfeel. There are various other approaches worth investigating, as well, like spiking an apple pie with cranberries or candied grapefruit zest, replacing iceberg lettuce with arugula atop a burger or chicken sandwich, using beer in batters and coatings, or adding vinegar and salt to french fries. In each case, the secret to success is moderation and careful commingling. And the results can literally be mouthwatering.
Amble into any hip cocktail lounge or spirits purveyor these days and you’re likely to be astounded by the volume and range of bitters on display. At Alchemy in Oakland, California, the offerings number 50–60. Unsurprisingly, many boutique, artisan bitters-makers have sprung up to meet growing demand. A survey of your local liquor store’s offerings may now include everything from cardamom and grapefruit bitters to black walnut, rhubarb, and cranberry varieties. In cocktails, of course, bitters impart all sorts of intriguing flavors and flavor overtones to standard Manhattans, Old Fashioneds, and other classic concoctions. But now, they’re also being discovered by the likes of PepsiCo, which reportedly intends to launch Mtn Dew Black Label, featuring herbal bitters, in 2016.
Among other options: Hibiscus, with its unique cranberry-like flavor and acidity, offers a pathway to more memorable sodas, agua frescas, and juices. Adding unsweetened chocolate to milk can create a delicious beverage more akin to the thinner, more bitter chocolate milk originally consumed by the Aztecs. Shrubs—fruit and vinegar syrups that can be added to sodas and alcoholic beverages—are catching on in a big way among foodies and beverage connoisseurs. And kombucha, the fermented beverage with a bitter, slightly beery quality, is gaining traction as well.
All of which is to say, whether the order of the day is adding intrigue to standard menu items or launching a whole new beverage category, bitter and sour flavors may offer just the platform a clever menu-developer needs.