I'm not sure I know what an elderberry tastes like. I have a vague recollection of having elderberry tea or jam. Wikipedia says the raw berries are mildly poisonous, so I doubt I've tasted them.
This pours nearly perfect black, with only a slight tinge of purple. The beige head is dense, looking a bit like that from a Nitro can, but without feeling so artificial. The label says:
It is a rich black ale with aruit aroma, soft texture, roasted grain and red wine flavour, with a gentle finish.
Some of this is spot on, but the texture isn't quite so soft. For me, it's a tad over-fizzed. The "roasted grain and red wine flavour" is accurate, though. It's a bit like an oatmeal stout splashed with Cabernet. The fruitiness is subdued, and the berries are at least as tart as sweet.
I bought this as a single, but it's available as part of the four pack that includes Alba Scots Pine Ale, which I think I liked slightly better than Elderberry Black. Still, this is a fine ale and a very interesting one. The late Michael Jackson has an article which refers to St. Peter's Elderberry ale, but I don't think that's available in the States.