Cold brew has changed the coffee business

New York

SUMMER officially starts this year on June 21, but that is only the solstice, the day when the sun reaches its highest position in the sky. Down on street level, summer really begins on the first humid, sun-streaked day, when even the thought of sipping a hot cup of coffee is too much to bear. It is as if, just as birds know instinctively when to migrate, we wake up one bright morning and agree that it is iced coffee season.

Gregory Zamfotis, the owner of Gregorys Coffee in New York City, which is about to open its 24th location, starts tracking the temperature in early May.