Serious Eats: Recipes
Yusho's Two Tribes
Bar manager Alex Bachman's delicious, spirit-forward rendition of an Old Fashioned features a house-made barrel-aged stone fruit bitters. Bachman emphasizes the importance of aging the bitters in a used American oak barrel, which can be difficult to source. He either uses seasoned casks from Willett or the distillery's smaller 20-liter new oak barrels, which he then seasons with grain neutral spirit to remove primary wood tannin. Do not use new oak, he notes, as the wood tannins will overwhelm subtler flavors.
The aging process changes with what size barrels you use, but the general rule is that the smaller the barrel, the faster the aging will progress. It should be done to taste, but six weeks at a minimum in old wood is a good rule of thumb. You are looking for wood flavor to accent the compounds that are already macerated in the spirit: vanilla, brown butter, molasses, mulling spices, etc. Home users should consult Tuthilltown Spirits, which sells used 8-liter oak barrels.