Purify Your Water With a Carbon Stick

F. Martin Ramin for The Wall Street Journal, Styling by Anne Cardenas

The Eau Good water bottle

It may seem counterintuitive to purify your drinking water with a stick of charcoal, but the Japanese have been doing it for centuries. Binchotan—a carbon made from tree branches—is renowned for its ability to soften water and absorb impurities, including chlorine. The Eau Good water bottle, which hits stores later this month, promises to bring this ancient practice to Pilates and BOSU classes everywhere.

Technically, no fancy gear is required—just steep a stick in water overnight—but since there's nothing worse than getting "charcoal nose" when you're chugging water, Eau Good was designed to hold an included piece of binchotan in place. The solution is ingenious: Squeeze the bottle (it's made of BPA-free flexible plastic) until the stick settles into a dimple. To release, squeeze again.

The manufacturer recommends refreshing the charcoal after three months by boiling it for 10 minutes (purists would suggest refreshing binchotan every few weeks). After six months, you can put the stick in your refrigerator or sneakers to absorb odors, or crumble it into potting soil to fertilize and balance pH. (Unlike plastic water filters, most of which are also charcoal based, these sticks are completely biodegradable.) We binchotanized some New York tap water, and the difference in taste was drastic. But you can easily test the waters yourself. Replacement sticks are sold individually for $3.70, and they work with any container. $20, blackandblum.com