>>512724498
For people who don't know, bourbon is distinct from whisky because it is aged in charred oak barrels. The charring causes the trehalose (wood sugar) to caramelize which then goes into the spirit as it ages.
Optimally, the barrel wood should have been first "cured" by getting it wet twice a day and then letting it dry in the sun, for a few years. This removes the bitter tannins.

Fun fact: The "used" bourbon barrels are often shipped to Europe where they are used as "neutral" barrels for sherry and scotch.

>>512725776
Sherry was wine coolers before wine coolers.