Why iced coffee costs more:

The cold [coffee] will cost anywhere from a quarter to a dollar more. But the café will hardly claim the entire difference as profit. Like the hot stuff, cold-brewing involves mixing pulverized beans with water, but the latter process requires about twice as much ground coffee. Those grounds infuse filtered water for 12 to 24 hours, creating iced-coffee concentrate. That liquid is cut with water to taste, at a ratio of about one to one. Yet even after all this dilution, a cup of cold-brewed joe can include 62 cents worth of ground coffee. A hot cup might include 35 cents’ worth of beans.