Master distiller Billy Walker selected for this Masters of Wood expression some of the most exceptional casks in The GlenAllachie's inventory: ex-solera vessels that held Pedro Ximénez and Oloroso sherry for over 55 years. These casks are rarely released by the bodegas, and Walker describes them as carriers of 'more than half a century of sherry history' before ever touching the spirit.

The spirit was initially matured in American ex-bourbon casks, then transferred to the rare ex-solera sherry casks for secondary maturation. This two-stage approach layers dried fruit, chocolate and nutty depth from decades of sherry influence with vanilla, caramel and honey from the bourbon phase, balanced by the rich sweetness of Pedro Ximénez and the drier spice of Oloroso.