All of the stills in ‘Stillhouse 2’ remain directly fired (by gas). The size and shape of the stills have not changed since 1886 (see below) which seems to contradict Glenfiddich’s new make character – light, estery, pear and apple-accented. Small stills and direct fire are meant to combine to make a heavy style. Here, however, having an early cut point preserves that delicacy. The number of stills is another clue. More spirit could have been made with a smaller number of stills by widening the cut, but that would have meant that character would have been lost. The only solution was to add more stills.

That delicacy is seen most clearly in the 12-year-old. After that, a steady increase in the amount of ex-Sherry casks used adds increasing layers of fruit and weight but the light notes seen in the new make are never fully lost.

The firm has also pioneered (or maybe revived) a type of solera ageing. This involves a set recipe of mature stock from specific cask types being mingled together in a solera vat which is then never more than half emptied.

The technique was pioneered for the 15-year-old expression and now three more vats have been constructed for the Select, Reserve and Vintage Cask range. The vatting cask for the 40-year-old, containing whiskies from the 1920s, is also never fully emptied. Because none of the vats are fully emptied some of the original whiskies are still contained in the mix, something which adds mouthfeel and harmony to the final whisky.

Indeed, all Glenfiddich undergoes a marrying process – if not in solera vats then in marrying tuns where the component parts are allowed time to meld together. It is time consuming – and expensive – but William Grant & Sons believes it adds quality to the final product.