The oxygen contained in the water essentially contributes to the quality of tea, coffee and hot drinks. Water which stands in a water pipe or water heater for a longer time goes stale and looses its essential constituents. Also water from a hot water pipe or water already boiled before should be avoided. It contains less atmospheric oxygen and makes all drinks taste stale and insipid. In addition, fresh water has a low protein content, i.e. it does not contain any micro-organisms. Although these would disintegrate if they were boiled, they would for example, cause clouding in the tea.
Coffee also only develops its full aroma with water rich in oxygen. The water in the coffee machine should therefore never be left standing, but be renewed every day and the water container should be cleaned regularly. In order to keep the loss of oxygen as low as possible during heating, the coffee water should be heated up as quickly as possible. By no means should water from the tap be used and then boiled.