Whisky Bushmills 10 Year Old Sherry Cask Finish. Here we have a whole litre of the glorious Bushmills 10 Year Old Sherry Cask Finish. The folks at Bushmills have taken their triple distilled, Irish single malt whisky, and treated it to an additional stay in sherry casks, for an extra helping of rich honey and soft fruits, in this expression originally released for the Travel Retail market.