Classed as an aromatised wine within EU law, it is a blend of 85% Bordeaux region wines (Semillon for the blanc and for the rosé, Merlot for the rouge) and 15% macerated liqueurs, mostly citrus liqueurs (peels of sweet oranges from Spain and Morocco and peels of bitter green oranges from Haiti).
During the aging process, Lillet is handled as a Bordeaux wine (undergoing fining, racking, filtering, etc.).
In the original Kina Lillet formulation (so named with respect to its status as a quinquina), quinine liqueur made of cinchona bark from Peru was included among its ingredients.
The idea of making aperitifs in Bordeaux came from Father Kermann, a doctor who left Brazil at the beginning of Louis XVI's reign.
He returned to France and made Bordeaux his home, where he created liqueurs and fortifiers using herbs like quinine.
At the end of the 19th century, people developed a great fear of illness as a consequence of the discoveries made by Louis Pasteur (1822–1895).
Originally blanc, when all other aperitifs were red, Lillet was the only aperitif from a specific geographic location, one of the most famous, the Bordeaux region, or more precisely Great Sauternes region (at that time Sauternes was covering appellations that are now considered as Bordeaux or Graves appellation).
[1]: 141–156 At the same time, Lillet was served on transatlantic liners, part of the reason for its success with high society in New York.
Build over 3 large ice cubes in a tall wine glass and garnish with cucumber, mint and strawberry."