Bamboo charcoal stick to purify and mineralize water. Bamboo charcoal, also called Takesumi, has been used in Japan for centuries to purify running water by removing chlorine, pesticides, and heavy metals. This active vegetable carbon because it remineralizes water by providing calcium, potassium and silicic acid. It also helps balance the pH of water and reduces the unpleasant bleach taste and odor that goes with it. Khool Bamboo charcoal sticks are a natural and environmentally friendly solution to purify tap water at home but also on the go, by simply placing a Takesumi stick in your flask or insulated bottle.