Amaro is surely one of the strangest spirits ever to take up space behind a bar. But its unusual, diverse flavours make sense when they find a suitable playmate. Of all the worthwhile advice we can take from the 2001 Tom Cruise vehicle Vanilla Sky, the most sage might be these words from actor Jason Lee, in his role as Brian Shelby: "The sweet is never as sweet without the sour." I think he was speaking metaphorically (the movie was super confusing), but his sentiment applies to any bartender worth his or her arm garters. The key to constructing a memorable cocktail is the balance that flows from juxtaposing the sweet with something bitter-and that's why the back of the bar is usually littered with the odd labels and unpronounceable names that typify amaro. Amaro ("bitter" in Italian) is a catch-all term for a class of herbal liqueur that hovers around 20 to 30 percent alcohol; has a thick, palate-puckering flavour profile; and changes its label every 150 years or so to keep up with what the kids are doing. Amaro's initial purpose was to aid in the digestion of a large meal-indeed, its odd taste seems to operate in part as a tut-tut to a glutton's stomach. But in the hands of a freewheelin' mixologist, its nutbar flavours are like the arrival of Technicolor to a black-and-white filmmaker. Take venerable Fernet-Branca. Its smell has been described as "black-licorice-flavoured Listerine," and the company that makes it is rumoured to be the world's largest consumer of saffron; throw in some rhubarb and we're getting deep into the weird and wonderful. Cynar is a low-alcohol amaro based on artichokes that can be subbed in for Campari to steer a cocktail toward the earthy and strange. Becherovka, the Czechs' sole spirit offering, has a nice fresh ginger/cinnamon taste. And then there's head-scratchingly popular Jägermeister, the Dane Cook of amaros. Yes, they're odd fellows-not just with each other but within themselves (Averna tastes like both green pepper and caramel)-but that's their charm. Amaro Nonino ($40) From the famed Friuli distiller comes the class of the field: milder and lighter, it uses grappa as a based, then adds some spice and citrus peel. The XO amaro. Fernet-Branca ($30) Beloved in Argentina, where they cut it with Coke to make a truly terrible concoction. Try it with ginger ale for a slightly better take. Ramazzotti ($35) In 1814 – when this, the first amaro, was aerated – maybe blending myrrh and galangal was more common. These days it’s like a wacky and strong root beer.