It’s one of the three key authorised ingredients in whisky, yet its importance to the final flavour is often overlooked by many Scottish distillers.
Now, one of Edinburgh’s top universities and a new distillery based in Leith have revealed they are undertaking a comprehensive examination of the impact of yeast on the final flavours found in Scotland’s national spirit. One year in, the team say the study has already revealed some surprising results.
Funded by innovation agency Innovate UK, the Knowledge Transfer Partnership between Heriot-Watt University and the Port of Leith Distillery has set out to test the impact of more than 20 strains of yeast.
Victoria Muir-Taylor, the partnership’s associate distiller at Port of Leith Distillery, is the graduate from Heriot-Watt’s International Centre for Brewing and Distilling leading the research.
Picture: ICBD
She explained that the objective of the research is to determine how the choice of yeast contributes to the complexity of flavours found in Scotch whisky.
She said: “A huge amount of attention has been given to the type of cask used for maturation, but we want to focus on the early phases of the production process. We want to see what new characteristics we can bring out in a whisky from changing the yeast alone. We believe this is a key area for innovation.”
Until the mid-20th century, many whisky distilleries shared yeast with the local brewery or used a combination of a distiller’s yeast for alcohol and a brewer’s yeast for flavour and mouthfeel.
Since the 1950s, the most prevalent types of yeast used in Scotland have been M strains of S.cerevisiae. A new super-strain, called MX, has recently been introduced due to its quicker and more efficient impact on fermentation. Another strain, Mauri, originally from a baker’s yeast, is also still used.
Ian Stirling, co-founder of the Port of Leith Distillery, a major new whisky distillery and tourism landmark planned for a site by the Royal Yacht Britannia in Edinburgh, added that there are hundreds of commercially available yeasts and though not all are suitable for whisky distillation, many can create unique flavours in the new make spirit produced by the whisky distillation process.
He added: “Until recently, efficiency has tended to dominate the conversation about yeast. However, we’ve already seen a few companies conducting experiments with some wonderful results reaching the market. However, Scotland still lags behind the US in terms of innovation in this area.
“We have now reached the halfway point in our two-year research and development programme, in which we are experimenting with a wide range of yeasts and fermentations, drawing ideas from different sectors of the drinks industry.
“We want to find new flavours and styles that we can draw through to our distillate. There are a huge number of variables to consider, such as how long you ferment for and at what temperature, but we firmly believe that this research will be beneficial for the industry as a whole.”
The project has already identified brewing strains of yeast more commonly used for beer which possess promising characteristics for whisky production, with an ability to maintain the balance between alcohol yields and flavour.
Muir-Taylor stated that the project team would be sharing the results of the study with the industry at large when it is completed in September 2020 in a bid to benefit innovation and the continued growth and development of the Scotch whisky industry.
She said: “As one of Scotland’s key exports, it is essential that we continue to push boundaries.”
