With the enologist Pascal Ribéreau-Gayon and others, he revised and updated the two-volume “Handbook of Enology,” a standard text in the field.

That means "you may have high sugar content in the grapes but the maturity of tannin may be incomplete," said enologist Cristian Aliaga.

Heredia has a science background: Her first job was as a research enologist at Phelps, where she rebelled against “analysis paralysis.”