Water from maple and birch trees is an emerging trend this year, according to Zegler.

"It has been filtered through the tree, but has a sweet hint from the maple syrup," Zegler said of maple water. "It doesn't have the acquired taste that coconut water has. Maple and birch water is a little more crisp and clean and focuses on the hydration aspect."

While she said birch water hasn't hit the U.S. market yet, it's available in Europe.

Teas are also becoming more mainstream this year -- but not just as a drink. "Tea as a cooking liquid, as a rub or marinade, and used in sweets ... like a crème brûlée," said Christine Couvelier, a food expert and founder of Culinary Concierge.