Glenfarclas 12 Years Aged Highland Single Malt Scotch Whisky 750 MLAged in refill American oak casks before being finished in first fill European oak Sherry casks, DoubleWood is an excellent example of what the Balvenie distillery can craft, even at 12 years. This whisky was matured in American oak casks previously used to mature bourbon, before being finished in European oak casks previously used to mature sherry.