Boil three chunks of the Siberian birch mushroom for 20 minutes, this is the minimum time for this great tasting tea to work, and then strain it off. (You can keep the chunks in the refrigerator and use them again the next day, as long as the tea turns brown.) 

The mushroom is said to have healing properties, such as the relief of gastrointestinal complaints and the strengthening of the immune system. Whether folk medicine is right that it strengthens the body's defenses as well as endurance and performance of body is uncertain, in any case Chaga tea tastes excellent and thus generally contributes to well-being.