What a regauge records
A regauge certificate, typically issued by the bonded warehouse holding the cask, records the cask's identifying details (cask number, type, fill date and spirit description) alongside three measurements taken on the regauge date: the bulk litres of liquid remaining, the ABV (alcoholic strength by volume), and the resulting LPA — litres of pure alcohol, being bulk litres multiplied by ABV. LPA is the figure duty, yield and most trade pricing hang from; the calculation is set out in LPA explained: litres of pure alcohol.
Read the change, not just the number
The certificate becomes genuinely useful when compared against the original fill record. Maturing spirit loses volume and strength to evaporation — the so-called angel's share — and to absorption into the wood. A gradual, steady decline across the cask's life is normal and expected. What a professional reader looks for is the pattern: losses broadly consistent with the cask's age, type and warehouse conditions suggest a sound cask; losses well outside the expected range can indicate a leak, a poorly seasoned cask or storage problems, and each of those has a price.
The ABV trajectory matters commercially
In Irish maturation conditions, strength changes over time and may decline depending on warehouse conditions. That trajectory has a hard commercial floor: spirit must be bottled at no less than 40% ABV to be sold as whiskey. A cask sitting comfortably above that level has time and options; a cask whose ABV is trending toward the minimum has a shortening commercial runway, and a buyer will price the urgency. This is one reason an old cask is not automatically a more valuable cask.
Recency is part of the evidence
A regauge is a snapshot, and snapshots age. An older regauge may no longer reflect the cask's current volume and strength; the need for a fresh measurement increases with time. Credible sellers commission a fresh regauge before going to market; credible buyers ask for one before committing. Where samples are drawn for assessment, the sampling should be documented on the same disciplined basis.
The certificate in a wider evidence pack
The regauge sits alongside the ownership documentation, the warehouse records and the fill history to form the evidence pack behind any defensible transaction or commercial valuation. A strong regauge cannot rescue weak title, and clean title cannot compensate for a cask that is emptying faster than it should. It is the combination that a buyer's due diligence — and Celtica's own verification stage — examines.
Official sources and further reading
Regulation (EU) 2019/787 on spirit drinks (the 40% minimum strength referenced above); Irish Revenue — producing, holding and storing excisable products (tax warehouses, where regauged stock is held).
This resource is a commercial and educational reference. It does not constitute legal, tax, excise, customs, investment or financial advice. Figures and patterns described are general; always rely on a current regauge and your own verified records in a live transaction.