The Speyside-based GlenAllachie Distillery, has announced the launch of the fourth release in its limited-edition Sinteis Series.

The GlenAllachie Sinteis Part IV (58.5% ABV) is a 10 Year Old cask-strength single malt Scotch whisky. It was initially matured in ex-Bourbon barrels before being separately matured in Pedro Ximénez and Oloroso Sherry casks, before combined and transferred into rare Mongolian virgin oak casks.

This latest release is said to reflect The GlenAllachie’s pioneering approach to wood mastery and the continued evolution of the Sinteis Series. The fourth edition embodies the ethos of ‘A Convergence of Three: Three Casks, Three Stories, One Exceptional Whisky.’

‘Sinteis’ (pronounced sin-teesh), meaning ‘synthesis’ in Scottish Gaelic, captures the essence of The GlenAllachie’s cask innovation, uniting bold and expressive virgin oak with the familiar warmth of Sherry casks to create distinctive, boundary-pushing expressions.

Mongolian virgin oak casks, crafted from Quercus mongolica, are hard to source and unforgiving in character. Consequently, this wood type has remained largely unexplored in Scotch whisky. The oak is scarce in nature, having to grow for more than a century and be naturally felled before it can be used commercially. Sourced from forests in East Asia and noted for its tight grain structure and remarkable density, the wood reveals rich caramel, subtle sandalwood and oriental incense nuances.

Sinteis Part IV showcases this harmony through two types of Sherry cask. Oloroso infuses the whisky with layers of dried fruit, dark chocolate and nutty complexity, while Pedro Ximénez brings sweet toffee and treacle. The final whisky reveals dark chocolate, layered orchard fruits and warm pastries – a celebration of each cask’s distinct character, converging perfectly into one.

The GlenAllachie Sinteis Part IV, is described as delivering notes of baked pastries, butterscotch, brandied orchard fruits, cocoa, treacle tart, cinnamon and crystallised ginger on the nose. On the palate, notes of candied hazelnuts, baking spices, plum syrup, spiced baked orange, vanilla ice cream, mocha, mānuka honey and fig jam emerge.

Commenting on the launch, Billy Walker, Master Distiller, said: “The Sinteis series has allowed us to explore the interaction between different virgin oak and Sherry casks. The series has explored dual-cask maturation in considerable depth already, so for Sinteis Part IV I wanted to introduce a different approach that would be both a challenge and an adventure.”

“We work intensively with Pedro Ximénez and Oloroso Sherry casks, so moving the liquid into Mongolian virgin oak was certainly an exciting challenge. The wood’s unforgiving nature and rarity in whisky-making meant we had little precedent to work from. As a team, we trusted our instinct and experience, and I’m exceptionally proud of the whisky we’ve created and of being able to showcase the beautiful character of Mongolian oak.”

The GlenAllachie Sinteis Part IV is now available from the distillery’s website and selected specialist retailers, for a RRP of £75.99.