Cask Companion — by Tankyu Distillery

Estimate the angel's share, bottle yield and cost per bottle of a maturing whisky cask, and track your own cask's journey.

Cask Companion is a small tool for anyone curious about whisky cask ownership, made by the team at Tankyu Distillery (丹丘蒸留所) in Higashikawa, Hokkaido. CALCULATOR Choose a cask type, fill strength and climate, and estimate: • How much spirit the angels will take (evaporation loss, compounding yearly) • Estimated final ABV after maturation • How many 700 ml bottles your cask will yield, at cask strength or diluted to 46% • Cost per bottle, if you enter a cask price Climate matters: a cask maturing through Hokkaido's 66°C annual temperature swing behaves differently from one in a Scottish dunnage warehouse. The calculator includes presets for Hokkaido, Scotland and subtropical maturation. MY CASK Already own a cask — or planning to? Enter the fill date and target age, and Cask Companion tracks days matured, days to bottling, and maturation milestones, including the three-year JSLMA Japanese whisky standard. Data is stored locally on your device only. All figures are estimates for curiosity and planning — real maturation varies with warehouse, wood and weather. No data is collected or transmitted. Made with patience in Higashikawa, Hokkaido — the town where today's snow becomes tomorrow's whisky.