Aging Tequila
02. Introduction to Wood Science
There are 2 primary species preferred for cask-making in tequila: Quercus alba or American white oak and Quercus petrea or European white oak. Each species offers slightly different flavor profiles. Additionally, the climate where the oak grows also affects flavors. So for example, spirits aged in Quercus petrea from Allier, France will taste different from spirits aged in Quercus petrea from the Zemplen Mountains forest in Hungary.
The major distinguishable physical difference between oak species is their density. European oak tends to be more dense (closer spaced rings) which impart less oak lactones and oxygen than American oak. Generally speaking, both American oak and European oak are ideal for aging tequila, because the spirit does well handling American oak’s robust flavors and oxygen ingress (when oxygen dissolves in the liquid over time, also known as oxidation), while at the same time aging in European oak imparts more delicate, spicy and fruity flavors.
BARRELS — Añejo and extra añejo tequilas must be aged in barrels – the majority of which come from the Bourbon industry, who, by law, can only use them once.
Flavor Compounds from Oak
How oak and its toast level introduce flavors into tequila varies by cooperage house style and producer specifications. A handful of compounds play the dominant roles in what flavors a barrel imparts to tequila. Each reacts to heat.
CIS- AND TRANS-OAK LACTONES
woody or coconut flavors
FURFURAL
dried fruit, burned almonds, burnt sugar, sweetness, light caramel flavors
EUGENOL
spices, cloves and smoke character
GUAIACOL
Burn overtones
OAK LACTONE
woody, dill and coconut notes
VANILLIN
vanilla
SYRINGALDEHYDE
vanilla-like