Losing spirits to evaporation during maturation is an accepted part of the distilling business. However, The Scotch Bonnet Company believes it has an answer.
For generations reducing the Angels’ Share, loss to evaporation when maturing spirits in oak barrels, has perplexed the drinks industry.
But now a Dundee-based business has come up with a revolutionary solution to this age-old problem.
The Scotch Bonnet Company has invented a specially-designed “cap” that is placed on the top of palletised spirit barrels which is intended to slow down the evaporation loss.
From recent controlled tests it has saved as much as 5.5 kilos of cask strength spirit per barrel over a 42-month period.
“The bonnet came about through our main business interests, which is constructing maturation bonds for the Scotch Whisky industry,” said co-founder Ross Morrison, who is also chairman of Inverness Caledonian Thistle FC.
“The bonds that we have built were all for palletised barrels. Barrels that are stacked upright. In our time in the industry one of the main complaints from distillers has been the loss of whisky due to evaporation. The Angels’ Share.”
“My good friend of 40 years – (Cardboard) Ken, owns a packaging firm down south. He’s an expert in all things par, cardboard and fibreboard. We put our knowledge, experience and skills together and ‘The Scotch Bonnet’ was born!
“We were carrying out some building work for a major drinks manufacturer at the time and asked their head of maturation if he’d give us his professional opinion of The Scotch Bonnet.
“Immediately he loved it and although he suggested we changed some aspects of the design, he was convinced the basic principle of the bonnet would work. He agreed at that time to run controlled tests on the bonnet at one of their large maturation sites.
“To get such a positive and enthusiastic reaction from someone that is very well respected in the industry gave us a great deal of encouragement and bonnets were duly delivered.”
With tests having been run, the results were extremely positive, confirming that the bonnets did indeed reduce the amount of liquid lost to evaporation.
“The readings and weights we received from the tests confirmed that, on average, the barrels that had our bonnets on them, saved 5.5kg of cask strength spirit compared with the control barrels with no bonnets.
“The spirit was disgorged and used in blending, proving that the quality of the bonneted spirit was the same as the control barrels. The bonnet cut down on evaporation loss while not affecting the spirit. No taste difference. This was tremendous news.”
Having tested the product in the relatively cold climate of Scotland, it was then time to take the bonnets into warmer climes.
“The next thing that I felt we needed was to be testing in a warmer climate. I had met a chap by the name of Ian Chang who was global brand ambassador and master distiller of Kavalan Whisky of Taiwan at a couple of whisky events and made it my mission to get the bonnet over to Taiwan and on Kavalan casks,” continued Ross.
“After much cajoling, I finally met Ian at a dinner in London and having been armed with a specially-made mini Bonnet, Ian agreed to test them for us in his distillery over in Taiwan.
“We sent them over in June 2019 and in June 2020 I contacted Ian for an update, albeit with as much expectation as trepidation on my part. Ian confirmed that they had most certainly worked, cutting down spirit loss, with no change to the spirit structure and was really excited to start using our bonnets in his new distillery in Japan.
“As Ian said himself: ‘The Scotch Bonnet is a glaringly simple idea. In my experience, it significantly reduces cask losses with no effect on taste or spirit structure… In short, it works. Simple, innovative efficiency.
“I was delighted to be able to attribute these words from someone such as Ian.”
And another vote of confidence was provided by another well-known authority on whisky.
Charlie Maclean, of whom The Times described as “Scotland’s leading whisky expert”, author of 17 books on whisky, Master of the Quaich described the bonnet as: “This is a remarkable breakthrough in the war against the Angels.”
Spreading the word
The tests are now continuing with The Scotch Bonnet Company sending caps all over the world.
“At the moment we have several batches going out to places such as South Africa, Fiji, Mexico, USA, Finland and Ireland. These will join the testing distilleries that are going on in Scotland and the rum distilleries in the Caribbean. We need to spread the word,“ added Ross.
“All the results and reactions we have had up to now have been very positive. The results we have had are massively encouraging and when the results come in from the other spirit producers we hope that they will prove that the bonnet can produce the same savings on rum, tequila, Bourbon, Canadian whisky, Irish whiskey etc., basically anything that matures in a wooden cask.”
Anyone looking for more information can visit the website scotch-bonnet.com