When you belly up to most cocktail joints these days, one of the first things you’re likely to see is a bunch of strange, small bottles lined up proudly along the bar, with names such as Reagan’s and Peychaud’s. And behind the bar, alongside some familiar whiskeys and gins, the shelves are often dominated by hard-to-pronounce bottles that the bartenders seem to use for almost every drink.

Despite being in almost constant use, all of these ingredients—which fall under the family of bitter herbal liqueurs called amaro (literally Italian for bitter)—are among the least understood by drinkers. Whether it’s a few shakes of Angostura or a half ounce of Campari, they are the silent players that make cocktails work, adding depth, flavor, and balance to soften the edge of straight spirits. They are also at the heart of the current cocktail scene, which has veered away from cloying sweetness in favor of complex bitterness.

To gain a better understanding of the wide world of amari, we chatted up bartender and bitter aficionado Sother Teague. As beverage director at Amor y Amargo (443 E 6th St between Ave A and First Ave, 212-614-6817), he spends many nights behind the stick schooling patrons on all things bitter through side-by-side tastings and amaro-centric cocktails. There’s no shaking of mixers, no fruit juice to speak of, and no sugar added to anything. Amaro rules all at the East Village den aptly named love and bitters, which displays 30 tincture bottles on the bar up front and 90 amari behind that.

There’s no denying that this class of booze is intimidating—not least because most amari are often created with top-secret formulas that their creators refuse to share, leaving drinkers to do a lot of guesswork about what they’re even tasting. But it’s also an endlessly rewarding category, and one that will give you insight into what makes a lot of your favorite cocktails great, from Manhattans to Negronis.

Here, amaro master Sother Teague guides us through the basics of bitters, breaks down the easiest ways to play with amari in classic cocktails, and explains why every home bar should have a bottle of Cynar in it.