A digestivo that's part of the class of Italian bitter liqueurs known as "amari," Fernet Branca is unlike any other spirit on the shelf--and that can be either a blessing or a curse, depending on which side of the Fernet Branca battle you're on.
The flavor is engagingly bitter, memorably potent and as Curtis notes, almost indescribably complex. Despite these vagaries, Fernet Branca has a double-barreled character that tends to inspire strong passions: as Curtis writes, "in 1960, Betsy von Furstenberg was suspended from Actors' Equity for spiking Tony Randall's onstage drink with it. Randall believed he had been poisoned with iodine."
While many bitter liqueurs such as Campari, Jägermeister, and Averna have garnered equally passionate fans and detractors, Fernet Branca takes the volume of these arguments and turns it up to eleven.
I know many people with well-seasoned palates who find themselves flummoxed by the liqueur's powerful flavor, and many others--inexplicably concentrated in the San Francisco area--who consider Fernet Branca an essential part of their diet, and who couldn't imagine a back bar or liquor cabinet without the distinctive dark green bottle.
Fernet Branca may have its detractors, but Curtis writes that this group may be shrinking:
I'd be willing to wager that Fernet will spread beyond the Bay Area. The taste is big, and America is having an extended love affair with big flavors. And bitter, which had a heyday here in the late 19th century, seems to have a renewed allure. Think of Starbucks, Jägermeister, and those barbed, hard-to-swallow salad greens now found even at the Piggly Wiggly. This rediscovery is a good thing, extending the palette of our palates. Bitter is one of just five or six tastes that our receptors can perceive, and ignoring bitter is as ill-considered as a painter eschewing a primary color.