Ice and water are placed in the top jar, and by regulating the dripping water through the valve in the center, coffee is steeped and ends up in the carafe at the bottom of the tower. It's easy to use. Just put the water and coffee grounds into the brewer and set the brass fitting for the desired drip time. A permanent ceramic filter mechanism is included. This cold drip tower holds 124oz (approx 3.67 Litres). By slowly brewing your coffee with ice water, the harsher oils in your ground coffee are not brought out leaving you with a clean acid free coffee.