Undiluted, the attack is very soft, the texture silky. There's some sweetness and meatiness from the sherry casks, then the savory elements take over and a wave of salt builds up and comes roaring in over the mid-palate. Toward the death, there's a growing spiciness - almost as if this were Talisker - and additional floral and herbal elements. The wood kicking in, in other words. Without added water, the finish is syrupy sweet and faintly woody-vegetal, a bit like the aftertaste of an herbal cough drop. So without any added water, I'd say this is very okay (and oaky, haha) stuff, but nowhere near the 250 € category, where this is priced at.
With water, the barley comes out more, things get maltier and a bit "brighter," i.e. the dark, sherried aspects recede. Now there's also some citrus and perhaps a distant echo of pulped exotic fruits (papaya, guava). The sherry tones, now providing the background rather than the figurehead, tend toward musk, leather and (again:) espresso. Not a huge improvement with water, I'd say.
On the palate, the body has lost some substance with water, the attack is much diminished (even a bit thin now), as is the saltiness. The spicy and herbal aspects hold up best, but all in all, the malt gives off the impression that it has already been diluted to the exact sweet spot the blender had selected, and that adding more water just makes things flabby and less interesting. Not a good swimmer, then, this one. Ah, and oh yes: the finish, too, loses with water.
Overall, this is a nice designer whisky that fails to deliver the goods. Not what you'd hope for in a bottle this expensive. My advice: if you're looking for a dark, well-sherried and substantive "modern" whisky with some oomph and a much better finish, opt for the 17-year-old Highland Park "The Dark," which provides a similar, but more pronounced experience, for roughly 100 € less.