Muddy York Brewing Co. in Toronto has been releasing seasonally imperial stout aged in sherry, port, or Cognac barrels. This bottle dates from 2019, to my best recollection. The website describes it in these terms.
The beer is a clear success for this taster. At this stage, it must be four and a half years old, as it was bottled after 18 months in Fino barrels.
There is clearly a slight undertone of the sherry, dry and flinty as the brewery’s description suggests, but married to the richness of the stout. Gums from the wood likely contribute to the lush effect.
As one conscious of wood types used to age strong stout and other beer, I mulled what type of wood went into the barrel.
It was probably American oak, which is the type generally used in the Spanish sherry industry and has been for centuries. I don’t say for all types for all producers, but in principle.
The Sherry Wines Vinos de Jerez website states:
Of the hundreds of oak species, American White oak (Quercus Alba) is the chosen type for Sherry producers. It comes from the eastern half of the USA and the best source is between the Ozarks and the Appalachians, south of the Great Lakes. Here it grows in huge forests and thus grows tall and straight giving good yields for barrel staves. It was in use in Spain by the second half of the XVII century.
This accords with information I have gleaned over many years. The Inkwell does to my mind suggest an influence of American oak, but it is not the coconut/vanillin taste often encountered in bourbon barrel-aged imperial stout (BBIS).
Also, the “boozy” element many identify in BBIS is absent. Of course the typical taste of BBIS is informed in good part by the whiskey, or rather residual spirit in the wood frame, whereas sherry will impact the beer differently.
It should be borne in mind too that bourbon is always aged in new oak barrels. The barrel has more to give to the whiskey, and later the beer, than for sherry aging, where the barrels would, as in most wine-making, be reused many times.
For these reasons the taste of Inkwell, or this iteration, is different to BBIS, yet still there is a hint of American wood influence (imo). It comes out here as weathered oak and light tannins.
The hops are tamped down from the years in wood and bottle but still support the malt. The sherry and light wood tones blend seamlessly with them to create the special magic – at its best – of imperial stout.