Loiseau, her successor, is the youngest to take the title. Before being appointed as Trichet's deputy in 2012, he studied the impact of aging conditions on the quality of the eaux-de-vie, experimenting with ways to improve its quality. "It's the first part of the job to be a scientist," he said.
Trichet, with Loiseau translating, called her appointment in 2003 "a sign of audacity." And the appointment of a cellar master so young as Loiseau? "Also a sign of audacity," he said.
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Cellar masters are tasked with overseeing the process of making cognac, from grapes to glass. Each year, they direct the distillation of the eaux-de-vie, a colorless fruit brandy usually made from ugni blanc grapes, which is then aged in French oak barrels for at least two years and maybe as many as 40. Many of those eaux-de-vie will be used in the house's more widely available cognacs.
Eaux-de-vie may be moved to different casks over the years and blended together, eventually transferred into glass demijohns to halt the aging process, said Jerald O'Kennard, director of the Beverage Testing Institute. (In that way, one year's harvest may eventually account for dozens of eaux-de-vie.) The cognac may linger in those vessels for decades more. "Those old stocks give character to the younger stocks, when blended in," he said.
A cellar master's challenge is to uphold the style of the house, said Trichet. That means there's no need to anticipate the tastes of an audience decades in the future. But it also requires skill: Today's Louis XIII must offer a similar drinking experience to the one available a century ago, and what will be on offer in another 100 years. "Perhaps the hardest thing, you have to recreate every year the same blend and characteristic style," she said.
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Tasting older blends can provide a blueprint for cellar masters to reverse engineer, figuring out where they want to go, O'Kennard said. It also helps them track that rare older blend worthy of its own release, without adding other eaux-de-vie. During her tenure, Trichet discovered two—which were released as Louis XIII Rare Cask 43,8 and Louis XIII Rare Cask 42,6.
"It was the right moment, the perfect balance of aromas and alcohol strength," she said of discovering the Rare Cask 42,6 with Loiseau. "It's Mother Nature doing her job. We are just here to reveal what is going on in the cellars."