
Amber bitter liqueur is a bittersweet herbal liqueur, usually Italian, made by flavoring a spirit base with bitter and aromatic botanicals, amber in color.
The amber bittersweets sit in the middle of the aperitivo scale: less bitter than the red bottles, sweeter and lighter. Their neighbors differ on two axes at once — bitterness and strength — so a swap almost always means correcting both.
Red bitter aperitivo (Campari-type)
Gentian in front, more bitter and drier, and it turns the drink red; in a Negroni pour about a quarter less of the red one and add half a barspoon of syrup.
Sweeter and half the strength — around 11% ABV against 28%. It will carry a spritz, and in a stirred drink the strength drops and the sugar has to come down.
A wine base instead of a spirit one: sweeter, softer and much weaker. It covers the sweet half and not the bitter one, which comes back as a couple of dashes of bitters.