Cask & Maturation

In Britain, a spirit may only be called whisky after at least three years in wood, and the same rule applies in Wales. For all four distilleries, this period almost always begins in the same cask: a used bourbon barrel made of American white oak, previously used in Kentucky or Tennessee.

For its best-known bottling, though, the bourbon cask alone isn't enough for Penderyn. The whisky then moves on once more, into casks that previously held Madeira wine from Portugal. There it picks up its golden colour along with a hint of raisin and caramel. This two-stage pattern, bourbon first, then Madeira, is something of the distillery's signature.

At Coles, by contrast, it's a single cask type throughout. The entire single malt matures there for five years in used Jack Daniel's barrels before leaving Carmarthenshire in bottle.

How much whisky evaporates in the process, the so-called angels' share, depends heavily on the warehouse climate. Wales sits damp and temperate on the Atlantic, without the intense summer heat that empties casks much faster in places like Texas or Kentucky. Maturation there proceeds correspondingly slower and more evenly than in those regions.

At the coastal warehouse of In the Welsh Wind, the damp sea air makes itself particularly felt. The moisture keeps the cask staves well sealed, so less alcohol is lost. In return, the whisky's typical concentration over the years takes a little longer to develop than in a drier warehouse. In the end, more of the cask comes through in the glass than elsewhere.