The filter is a cloth bag shaped like a sock, hung from a wooden stand — a brewing method Costa Ricans have used for roughly two centuries, long before paper filters existed.
Café chorreado is brewed by pouring hot water over ground coffee held in a cotton cloth filter called a bolsita or 'coffee sock,' which drips directly into a cup or pot below. The wooden stand-and-cloth setup, called a chorreador, is still used in homes and traditional sodas (diners) across Costa Rica for the daily café de la tarde.