Suze is a gentian liqueur and is a key ingredient in a White Negroni. It is the bitterest of the group and also claims the highest proof. Other gentian liqueur include Salers and Avèze. Avèze is the softest, and most mellow, of the gentian liqueurs listed here. While Salers can best be described as an great in between option, it also uses no artificial coloring, resulting in a pale straw hue. Depending on which gentian liqueur is used in a White Negroni will effect its color and taste.