Bitters are a highly concentrated botanical infusion of roots, herbs, and spices used to flavor drinks. They are made from a neutral alcohol base infused with various botanicals such as spices, barks, fruits, roots, flowers, leaves, and herbs. The botanical ingredients used in preparing bitters have consisted of aromatic herbs, bark, roots, and/or fruit for their flavor and medicinal properties. Some of the most common ingredients include cinchona bark, gentian root, cascarilla, orange peel, and others. Bitters typically have an alcohol content ranging from 35 to 45% ABV (alcohol by volume), but alcohol-free bitters are also available. The exact recipe of what is in bitters is often a closely guarded secret, but they are made by meticulously combining and macerating various ingredients to extract their flavors, resulting in a complex, intense extract.