Kishu Charcoal - Activated Charcoal Water Filter for Pitchers Kishu is the green way to filter tap water Kishu is activated charcoal made from oak tree branches Kishu is easy to use - simply place in a pitcher of water add tap water and watch Kishu go to work. Kishu is the green alternative to plastic filters like the Brita One stick lasts 4 months. Then it can be reused as a deodorizer in the refrg.