What does a cooper do in whisky?

A cooper builds and repairs the oak casks in which whisky matures, from taking apart a worn cask to testing a repaired cask.

The Scotch Whisky Association describes the trade as making and repairing oak casks. That involves more than hammering: inspecting casks, judging the quality of the wood, stacking casks and keeping a record of what has been done to each cask.

In practice a cask is first cleaned with a steel brush. The cooper looks for cracks and damage and marks them with chalk. Worn staves are removed and new staves are selected by weight and curvature and set into a temporary hoop.

Then the hoops are driven tight, the head goes in with reed as sealing, and the cask is tested for tightness. A cask that cannot be saved is set aside and sold as wood.

Training as a cooper in Scotland is a four-year apprenticeship on the shop floor, which ends with a practical test in the final year.

The first three years cover the history of the trade and the handwork. In the fourth year machine coopering is added. Whoever passes the test may approve casks independently.

Many apprentices start young. At Scottish cooperages they often start at sixteen, and at a large cooperage in Clackmannanshire dozens of apprentices work alongside at the same time. It is hard work: standing for long periods, lifting heavy loads and working in warm, damp sheds.

For a permanent position as an experienced cooper, employers count on three to five years of experience in cask work. You do not learn this trade from a book, then, but alongside someone who has been doing it for years.

A cooper is paid per cask and at the cooperage in Craigellachie finishes an average of twenty casks per eight-hour shift.

Piecework is customary in this trade. The pay depends on the number of casks someone finishes, not on the number of hours worked. At other Scottish cooperages, people speak of twenty-five to thirty casks a day.

Each cask stays with the same cooper from start to finish, until it is approved. The pace is therefore high, but the responsibility for each cask also rests with one name.

Building new casks is the exception here. Most of the work is repair: making an existing cask tight and usable again, so that it can go through another round of maturation.

After three or four fillings a cask gives off too little, and then the charred inner layer is removed and re-charred.

Every cask goes over the fire before use. At Scottish cooperages a cask is toasted for about forty minutes. Casks used for bourbon must also be genuinely charred on the inside; sherry casks are not charred.

After a number of fillings that layer is spent. A mechanical wire brush removes the charred wood, after which the cask is charred again. Charred casks then go under the steam, so that the wood regains moisture.

That way a cask can last for decades. That is where the terms first fill and refill on a label come from: they say how often the cask has already held whisky.

A cask that seals well and is properly charred determines a large part of the colour and flavour of the whisky in your glass.

The law sets the floor beneath that flavour. Scotch must mature for at least three years, only in Scotland, and only in oak casks with a capacity of no more than 700 litres. A standard cask of about 190 litres stays well below that.

A badly assembled cask leaks or does not release its wood properly. That is why every cask is tested before it goes into the maturation warehouse. At some cooperages, pressurised air and a few litres of water go into the bunghole, and the cask must pass that test.

Wilt u het verschil proeven tussen een vat dat eerder bourbon hield en een vat dat eerder sherry hield? Kom langs in Bathmen, dan zetten wij twee flessen naast elkaar en leggen wij uit wat u ruikt. Verkoop uitsluitend vanaf 18 jaar, NIX18.