Brewing yeast achieves ‘promising’ results in whisky production

A study being carried out by Heriot-Watt University and the Port of Leith Distillery has found that certain strains of beer brewing yeast “possess promising characteristics for whisky production”.

The project, which is called the Knowledge Transfer Partnership (KTP) and is funded by Innovate UK, will test over 20 strains of yeast over two years. The aim is to determine how each strain contributes to the flavour complexity of the whisky.

The study notes that until the mid-20th century, many whisky distilleries shared their yeast with the local brewery or used a combination of both brewer’s and distiller’s yeasts to improve the flavour and mouthfeel.

Since the 1950s, however, M strains of saccharomyces cerevisiae have been mostly used for whisky production in Scotland. MX, a new so-called super-strain developed in the 1990s, was recently introduced after it was found to initiate a faster and more efficient fermentation. Another yeast strain called Mauri, originally sourced from a baker’s yeast, is also used. Brewer’s yeast, however, has been virtually phased out of the production process.

One year into the study, Victoria Muir-Taylor, the project’s associate distiller at the Port of Leith Distillery, said it’s essential that the Scottish whisky industry “continues to push boundaries”.

A graduate of Heriot-Watt’s International Centre for Brewing and Distilling, Muir-Taylor is leading the research into how yeast contributes to flavour complexity 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.

“We will be sharing the results of this project with the industry at large to benefit innovation and the continued growth and development of the Scotch whisky industry.”

Ian Stirling, co-founder of the Port of Leith Distillery, added: “There are hundreds of commercially available yeasts and, while not all are suitable for whisky distillation, many can create unique and distinctive flavours in the new make spirit.

“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 study is expected to be completed in September 2020 with the findings due to be published.

Among the Scottish whisky distilleries known to be experimenting with yeast strains include Glenmorangie, Dornach and Kilchoman.

Meanwhile, in other fields, scientists have used used beer yeast to produce genetically-modified cannabis, while they’ve also isolated strains found in space. 

The Port of Leith Distillery, which has not yet been constructed, submitted a planning application for the construction of a £5 million site in September 2017.