Vermouth is an aromatized wine made from a neutral dry white basic wine which is then blended with an infusion. The infusion, which gives each vermouth its unique and distinctive character is created by flavoring the basic wine with a special selection of herbs, flowers, fruit peels, seeds, plants, and other botanicals. The addition of brandy fortifies the vermouth to 18% alcohol by volume. The prized and closely guarded recipe is used to make Boissiere has not changed since 1854.