Whisky The Macallan Rare Cask. The Macallan Rare Cask release introduced a new look for Rare Cask, designed to give greater insight into our whisky making process. This first batch was one of three batches to be released in 2018, with further batches planned for subsequent years. Each limited release batch represents the volume of only 50 oak sherry butts. Rare Cask's rich mahogany-red whisky showcases two of The Macallan’s greatest and most defining strengths - sherry seasoned oak casks and natural colour.