The first sight of the new distillery and visitor centre for The Macallan is a row of five meadow-topped domes, rising gently in the Speyside landscape. Closer in, you see that the dome roof is raised above ground, revealing, through a long glazed elevation, glimpses of the giant copper stills of whisky production. Once inside, the roof structure is revealed, a magnificent undulating lattice of timber beams, creating a dramatic enclosure to the distillery production processes. At 207 metres long the roof is one of the largest timber structures ever built, yet the homogeneity and consistency of detailing achieves an economical and efficient design. The Macallan, the distinguished single malt whisky, has been produced in Speyside since 1824, and its new building is set into the sloping contours of the estate grounds. It will enable whisky production to increase by a third to meet increasing global demand – 90 per cent of The Macallan is exported – but the company also wanted a building which would reflect its global status, be a worldclass destination for visitors and give the opportunity to entertain overseas distributors and clients. The architect Rogers Stirk Harbour + Partners with Arup as structural engineer have combined these requirements in a single building. The design has an extraordinary clarity, its elegance and simplicity the result of a careful analysis of the constraints and processes of distilling. The roof shape was a key decision. The exhaust of hot air above a circular template of equipment required height, so the apex of each dome is located above the hottest part of the process, the stills. The five repeating sets of stills and domes, capped with a covering of meadow grass, create a powerful symmetry, while externally mirroring the rolling hills of Speyside. To build a roof with a form of such complexity, with a clearly visible structure, relatively light in weight to allow it to float above the ground, timber was a clear and obvious choice. The first and highest dome encloses the main entrance and the visitor experience centre, where an exhibition and gallery introduces visitors to The Macallan and its history. The following three domes, arranged in a linear format, each house a circular set of copper stills. The final dome encloses the mash house, containing one of the world’s largest mash tuns. Other parts of the production process are housed in a deep concrete basement with counterfort retaining walls, extending in some parts to ten metres below ground level.