Quinine syrup. Herbal infusion. Bring the following ingredients to a boil, immediately turn down heat and simmer covered 30 minutes. Transfer to refrigerator, infuse overnight. Strain with conical metal strainer.
Cinchona infusion. Combine the following ingredients and infuse over night at room temperature. Strain with conical metal strainer, then with two layers of cheesecloth. 24 g ground cinchona bark (in coffee grinder) 600 mL vodka or Everclear
Decant herbal infusion to bottle and add 1/2 volume rich simple syrup (1:2 water:sugar by volume; about 1 cup). Add 4 oz cinchona infusion per ~600 mL herbal infusion. Refrigerate combined syrup; one serving is 0.5 oz (= ~24 calories).