Turkish coffee is unique because the beans are ground into an extremely fine powder—finer than espresso—and are not filtered out of the final drink. The coffee is simmered (not boiled) in a special copper pot called a 'cezve' or 'ibrik' with water and sugar. This method creates a thick, foamy beverage. The science of the 'foam' is crucial; it acts as an insulator, keeping the coffee hot for longer. Because the grounds remain in the cup, the coffee continues to brew as you drink it, leading to a very high caffeine concentration. After finishing, it is a tradition to flip the cup over onto the saucer and perform 'tasseography'—reading the patterns of the remaining coffee grounds to tell the drinker's fortune.