Cask inspection before filling

Why inspection pays

A 200 litre barrel filled at 63.5% ABV holds 127 litres of pure alcohol. Fill a musty or leaking cask and you can lose that spirit slowly to the floor, or worse, discover after years in the warehouse that it tastes of damp cardboard. Rejecting a doubtful cask on the filling floor is always cheaper. Our guide to cask filling strength explains why 63.5% is such a common choice.

Indian conditions add pressure. Imported casks may sit at a port or in a store for weeks in heat and humidity before reaching you. Dry casks shrink and open at the joints. Damp ones can grow mould. Ask your supplier how casks were stored and for how long. Inspect a sample from every delivery the day it arrives rather than the day you need it. Problems found on arrival can go back to the supplier; problems found at filling usually cannot.

Look at the outside first

• Hoops: all present, tight and not badly rusted. A loose hoop means a cask that will leak.
• Staves: no cracks, splits, worm holes or soft wood. Look closely at the croze, the groove that holds the heads.
• Heads: sound, sitting square in the croze, with no gaps.
• Bung hole: clean, round and undamaged, so a bung will seal.
• Markings: previous contents and fill dates legible, to match the supplier's paperwork.

Any cask with visible structural damage goes to the cooper or the reject pile, not the filling line.

Smell every cask

Smell is the most useful single check. Remove the bung, put your nose to the hole and breathe in gently. A good ex-bourbon barrel smells of vanilla, sweet oak and a little whiskey. A good sherry cask smells of dried fruit and wine.

Reject or set aside casks that smell of:

• Mould, damp cardboard or wet cellar.
• Vinegar or sharp sourness, a sign of bacterial spoilage in wine casks.
• Solvent, nail polish or glue.
• Sulphur beyond the faint match-strike some wine casks carry.
• Anything that is not wood or the previous liquid.

Train two or three people to do this and calibrate them together on known good and bad casks. One nose on a bad day misses things. Our guide to ex-bourbon, sherry and wine casks covers what each type should bring.

Check for leaks before the spirit goes in

Fill a doubtful cask with a little water, roll it and leave it for a few hours on a clean floor. Weeping joints show as dark, wet lines. Many dry casks seal themselves as the wood swells, so a slow weep that stops within a day is usually acceptable. A steady drip is not.

Some distilleries pressure test with low pressure air and soapy water on the joints instead, which is faster and keeps water out of the wood. Whichever method you use, drain completely before filling so water does not dilute the spirit below the strength recorded for excise.

Look inside with a torch

Shine a torch through the bung hole. In an ex-bourbon barrel you should see an even char layer. Patchy, flaking char or bare wood suggests the cask has been heavily used or poorly made. In wine and sherry casks look for residue, sediment or anything floating.

Check the cask's history on the paperwork too: first fill or refill, previous contents and how many times it has held spirit. Refill casks give less flavour and colour. That is not a fault, but it changes which spirit and which maturation plan they suit. In Indian heat, where wood extraction runs fast, a refill cask can be a sensible home for spirit you plan to age longer without it turning overly woody.

Record every cask

Each cask filled should carry a unique number linked to a record: supplier, type, previous contents, fill number, inspection result, inspector, fill date, volume and strength filled. That record supports your excise accounts, your insurance declarations and every future decision about when and how to bottle it.

Your first step: write a one page cask inspection checklist with the checks above and a pass, rework or reject box for each. Print it, pin it at the filling station and fill one out for every cask, starting with the next delivery. Count the rejects after a month and share the numbers with your cask supplier.