Winemag.com.-by Michael Schachner. – Grown in only a few of the world’s wine regions, dark, idiosyncratic Carmenère has found a comfortable home in Chile’s warm valleys.  Two decades ago, Jean-Michel Boursiquot, a French ampelographer hired to help wineries in Chile’s Maule Valley determine what grape varieties were in their oldest vineyards, dropped a bombshell on his clients. Thousands of acres that the Chileans had long thought were Merlot were actually an obscure variety called Carmenère. “Carmen-what?” the Chileans asked. Originally imported…