Around 1840 in Algeria, locals and French troops drank mazagran, coffee syrup cut with cold water, often called the original iced coffee. Italy later made frozen granita al caffe, and in 1920 the Joint Coffee Trade Publicity Committee pushed iced coffee in the United States to fix slumping summer sales. The chemistry sets three camps: cold brew steeps for 12 to 24 hours without heat and stays low in acid, double strength hot coffee over ice keeps the bright acids, and the Japanese flash chill drips hot coffee straight onto ice to lock in aromatics.

Other countries made it dessert. Salento pours espresso over ice with almond milk, Germany’s Eiskaffee adds vanilla ice cream and whipped cream, and Chile’s cafe helado brings cinnamon, dulce de leche, and nuts, with casein in the dairy binding bitter tannins. Vietnam drips dark coffee through a phin onto shelf stable condensed milk, and Greece shakes instant Nescafe into the frappe, whose spray dried proteins hold a lasting foam. In South Australia, Farmers Union Iced Coffee outsells Coca-Cola.

• Japan historically called cold brew Dutch coffee, a nod to trade with Dutch merchants.
• Thailand’s oliang is spiced with cardamom.
• The frappe gained global attention after the 2004 Athens Olympics.
• UCC Ueshima Coffee released canned liquid coffee in Japan in 1969.
• Tim Hortons iced capps helped drive a 16 percent jump in Canadian iced coffee popularity between 2015 and 2016.