Stated succinctly and with oversimplification, bitters are for modifying cocktails, and amari are for drinking. Amaro is usually served in 1-2 ounce pours as an aperitif or digestif. Because they were originally designed as “medicines,” they are widely believed to aid in appetite and digestion; bitters and soda is still a trusted remedy for stomach issues. While they can and do work well in cocktails, some like Fernet Branca can absolutely pummel all other flavors in the glass into insignificance, which is why it’s not a popular choice for mixing.
Bitters and amari begin as virtually the same thing; flavorful components like herbs, flowers, roots, and even leaves are chopped fine and macerated in ethanol in a process called tincturing. The fine chop is important because it exposes more of the component to the alcohol, thereby extracting more flavor. For bitters, the proof is left at about 40%. Because they’re not typically drunk, they are considered non-potable, a technicality that has been useful for distribution and is also completely untrue. While not recommended except for people with palates damaged from smoking, some cocktail recipes do call for up to an ounce and a half of bitters, so they’re quite potable in the strictest sense.
To make amaro, sugar in the form of demerara syrup is usually added as well as water. It’s the sweetness of amaro, followed by a noticeably bitter finish, that makes them so easy to like. Just as you think you’re getting a syrupy sugar bomb, the bitterness cleans everything up on the finish. With amari like Fernet Branca, a mentholating effect creates a lively mouthfeel similar to freshly brushed teeth or sucking on a breath mint.
