After you have removed the spent grains, one can add the wort chiller. This way during the rolling boil, the metal surfaces also get sanitized. After the flame is turned off, one can connect it to the cold water source. Wort chiller works through a simple heat exchange mechanism. The chilled water inside the pipe cools down the wort as it flows. In about 15 minutes, it can bring 35 liters of boiling water to room temperature.