Coffee is a brewed drink prepared from roasted seeds, commonly called coffee beans, of the coffee plant. They are seeds of coffee cherries that grow on trees in over 70 countries, cultivated primarily in Latin America, Southeast Asia, and Africa. Green unroasted coffee is one of the most traded agricultural commodities in the world. Due to its caffeine content, coffee often has a stimulating effect on humans.
Coffee, like most groceries, became quite scarce in Grantville in the first months after the Ring of Fire. At that time in history, it was only grown in the territory of the Ottoman Empire. Thus, the first trade item the town's leaders negotiated with Don Francisco Nasi for was coffee.
While coffee was known in Europe prior to the Ring of Fire, American influence made it popular, so coffee-drinking and coffeehouses spread through Europe decades earlier than in the OTL. In fact, coffee was not infrequently seen as an "American beverage".