Yerba mate tea is fast becoming the caffeine vehicle of choice for wellness-minded consumers far from its South American roots. That’s because yerba mate isn’t a commodity that responds to market signals, explains Raúl Karaben, a veteran grower. Yerba mate trees take years to mature and produce for decades to meet steady, culturally embedded local demand. Mixer boostIn Argentina, Uruguay, Paraguay and southern Chile and Brazil, yerba mate is traditionally imbibed through a metal straw. “Our daughter wants nothing to do with this,” said Nade Benvenutti, 60, who produces yerba mate with her husband outside Ilópolis.