Hillrock Solera Aged Bourbon is the world's first solera aged bourbon. Solera aging is a process that has generally been reserved for aging cognacs, ports and sherries. It involves filling a series of casks at intervals - as whiskey from the oldest cask is emptied and bottled, the cask is re-filled from the second-oldest cask in the solera. As the younger whiskey ages and cascades through the solera, its average age and complexity gradually increases over time. After cascading through the solera, Hillrock Solera Aged Bourbon is finished in 20 year old Oloroso Sherry casks. The finishing process balances the spicy rye flavors of the bourbon and adds further complexity, with layers of fig, roasted walnuts and candied fruit.