Years ago, in a bombed-out museum in La Plata, Argentina, I was offered yerba mate by a complete stranger. A winter chill whistled through the front wall left exposed by a tank, whilst a woman continued to warm water into her mate and offer it to those in the room. The hot burst of bitter liquid drew an invisible line connecting everyone in that gray, somber space. Mate is a caffeinated, tea-like infusion made from the dried leaves of the yerba mate plant. Often drunk hot, mate has an intense,…