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| Lignin: The Molecule |
Dr. Don
Livermore of Wiser's/Hiram Walker, spoke on "the most underappreciated
molecule", lignin. Lignin is a complex organic compound that binds to cellulose fibers that hardens and strengthens the cell walls of plants. Lignin is a polymer consisting of various aromatic alcohols, and is the chief noncarbohydrate constituent of wood. The lignin is broken down and transformed via cooking
and distillation into compounds producing the flavor notes of clove and smoke,
as well as the particularly distinctive spicy note we associate spirits, from 4-ethyl guaiacol. Following
through to distillation, Livermore discussed how the yeast-derived flavors of a
spirit, fruity, floral, green grass, soapy, and sulfur are separated through
pot distillation: the sulfur removed by the copper of the still; the green
grass notes in the head cuts of distillation; the soapy notes in the tails cut.
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| Where the Flavors Come From |
In maturation
inside an oak barrel, that magical lignin comes up again, in a role Livermore
calls the "mortar to the bricks" of cellulose and hemicellulose that
make up most of the wood. When burned in the barrel charring process, the
broken down lignin products add to many of the smoky, phenolic components to
the aging spirit, while the cellulose and hemicellulose impart many of the
caramel-type flavors.
Livermore
finished with some counter-intuitive experimental data showing that more char
on a barrel doesn't necessarily lead to more wood extractives in the spirit
aging inside of it. He found that a new barrel charred to two millimeters depth
gives more wood extractives than one charred to a four millimeters depth.
