Fernet is a bitter, herbal Italian amaro that originated in Milan in 1845, made from a secret blend of dozens of herbs, spices, and botanicals, including gentian root for bitterness. It is bottled at around 40-45% ABV, giving it a concentrated, minty, medicinal flavor profile.
In Italy, fernet is traditionally drunk neat or over ice as a digestif, believed to aid digestion after a meal. It also has a strong following outside Italy, notably as a bartender's staple in San Francisco and as a mixing base for cocktails such as the Hanky Panky and the Toronto. Fernet-Branca remains the best-known producer, though regional versions exist, including Fernet-Vallet (Mexico) and Leopold Bros. Fernet (United States).