De-char / Re-char at the Cooperage

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De-char / Re-char at the Cooperage

Coopering of casks is an age-old skill, the nuances of which have seen little change over the centuries. At Loch Lomond Whisky we’re fortunate to be one of only four distilleries in Scotland to have our own on-site cooperage. 

Our team of 10 seasoned professionals and eager apprentices carefully manage the quality of all of the casks to ensure that the whisky is maintained to the highest possible standards.

Our expert team examines every new cask that arrives on-site, they carry out repairs and maintenance on oak casks from all over the world.  They even rejuvenate casks using our De-char / Re-char (DCRC) process. Each year, our team maintains and repairs over 30,000 casks, which is absolutely vital in creating quality and consistency in our whisky maturation.

Cooperage Images

DCRC Process 

 Many distilleries will have a cooper or two on site to repair the odd cask, however when we say “Full service” we mean that our experienced team of 8 fully qualified coopers and three apprentices will check every new cask that comes on site, repair any casks from Bourbon to Sherry Butt AND rejuvenate casks using our De-char / Re-char (DCRC) process.   

This whole process gives us exact control over another element in the production of our whisky – which creates consistency, quality and allows us to really showcase our signature whisky style of fruit, honey sweetness and soft smoke.  

Most distilleries will tell you that they will use a cask 3 times, but such are the capabilities within our cooperage and the confidence in the experience of our coopers, mean that at Loch Lomond we can use a cask up to a maximum of 9 times! Three times for malt, the casks will then come into the cooperage to be checked, repaired if required, DCRC and then used three times for grain. Back into the cooperage to be checked, repaired if required, DCRC and then a further three times for grain. Consider that if the spirit is only in the cask for 6 years each time then we are using that cask for over 50 years.   

Coopering of casks is a skill that hasn’t changed much in centuries and this is probably best reflected in the tools you will see the team using at their stations. Coopering is a very physical job and the few modernisations/mechanisations you will see are helping to remove some of the most manual elements – helping to prolong the career of a cooper but also protecting their H&S.  


What is De-Charring? 

Loch Lomond Distillery was the first Scottish distillery to have this set up and the first to install this type of de-char machine.  All casks that we receive will have a level of char, most commonly ex-bourbon casks will come with a heavy char. This machine uses a Stainless-Steel wire brush that rotates and is moved up and down the cask as the machine rotates it (the cask). to the goal is to remove the char from the cask whilst taking the minimum amount of wood possible. This leaves us with a clean, consistent surface ready for a fresh char. The char is vacuumed out during the process but a little is always left at the bottom of the cask.   

What is Re-charring?

The re-char machine is uses a flame gun to char the inside of the cask.  Many factors impact how long this takes and the skill of the Cooper is to  use their experience and control the level of char that each cask gets depending on what is required by Michael and the distilling team. We will char a cask for anything from 2-3 minutes for a medium char up to 5 or 6 minutes for a heavy, alligator char. 

During the process you will see the nature of the flame change: 

  • Beginning will often be an orange flame with a blue/green tinge. This is burning of any alcohol in the cask
  • Charring – you know the cask itself is charring when the flame is a full bright orange flame and you can hear the crackles and pops. This means the cask itself is now alight. 

For medium char, the flames are extinguished using a spray of water but for heavy char we will turn off the flame and let the cask burn itself out.  

Before each cask that is re-charred has a chalk number on both the top and the cask ensuring that when the two are reunited that the correct top is married back to its cask as each top is a slightly different size and fit. We can often be re-charring dozens of casks per day, this is the simplest way to keep them together.  The casks are then taken next door to be finally tightened and pressure tested.    

De- char / Re-char Vs Shaved Toasted Re-charred Casks

What are the key differences? 

  • We do not “shave” our casks – the de-char machine uses steel brushes, removing the minimum amount of wood required, ensuring we maintain the integrity of the cask!
  • Shaved Toasted Re-charred casks have historically been ex-wine ALL of our re-chars are ex-bourbon. 
  • Re-char uses higher temperatures to caramelise the wood sugars faster than the gentler toasting approach.