Because fermented plant juices naturally turn sour with acetic acid, our ancestors discovered wine and vinegar together. In fact, a major challenge in winemaking was to delay this souring by limiting the wine’s exposure to the air. The Babylonians were making vinegar from date wine, raisin wine, and beer around 4000 BCE. They flavored their vinegar with herbs and spices, used it to pickle vegetables and meats, and added it to water to make it safe to drink. The Romans mixed vinegar and water to make an ordinary drink called posca, pickled vegetables in vinegar and brine, and judging by the late Roman recipe book of Apicius, often enjoyed vinegar in combination with honey. Pliny said that “no other sauce serves so well to season food or to heighten a flavor.” In the Philippines there developed a tradition of serving a variety of uncooked fish, meats, and vegetables in vinegar made from palm sap and tropical fruits. And the Chinese evolved dark, complex vinegars from rice, wheat, and other grains, which are sometimes roasted before fermentation.