Scientific and Lectures - the nerdy distilling - Blog post by Mads Thorup

Post by Mads Thorup

This time I have been thrown into tasting something from Scientific & Lectures (S&L) - and I may as well warn you straight away: this gets very nerdy, because I get into what yeast means for whisky. So start by finding yourself a good dram, and lean back before you read on. You may need a refill along the way ;)

S&L has spent a number of years experimenting with yeast and the fermentation process in whisky distilling. There is a strong focus on the science behind that process, and that is what their distilling is built on. Claus Rosensparre, who runs S&L, has a master's degree in biology and a PhD in health science. He became fascinated early on by the work of yeast and has been at it ever since. The interest has only grown bigger with time. Claus has tried isolating yeast from the surface of flowers and bees in order to investigate which types of whisky suit the different yeast strains he has cultivated. Listen to our podcast here:

Among other things Claus has made a yeast originating from sweet pea with aromas of pear, but he has 17 different yeast strains that he has developed, each with its own characteristics and personality.

Besides the slightly nerdy angle Claus has gained through his education and his passion for yeast, he also has experience in brewing and distilling, having been a brewmaster in Denmark and Germany. So he has good practical experience with distilling too. Claus' passion and knowledge about yeast is something he hopes to pass on to others, which is why he offers lectures. In these lectures he covers, among other things, the role of yeast in fermentation and what it means for the flavour profile, and the effect of wood types in maturation, where both the physical and chemical influence on the whisky's development is discussed. Beyond that you can learn about the mathematical models in distilling, formulas and methods for optimising production, plus some practical demonstrations of it. But much more about that can be found on their website.

I will now set off to taste some of their distillates and see what experiences I can get out of them.

The first sample I am tasting is at 46% alcohol. This new make sample is made with their yeast no. 2 (Saccharomyces cerevisiae), an attempt to recreate a yeast once used on small Danish farms but abandoned in favour of baker's yeast in brewing, since that was easier, meaning this yeast type was almost lost. This yeast is created from bees in Kerteminde and is said to give raspberry and cherry aromas. Local hard groundwater from Odense was also used for distilling this sample. The spirit has rested with staves soaked in rum, mirabelle brandy and bourbon, which should give the distillate aromas from those.

My notes are as follows:
The colour of the sample is very pale, close to transparent with a golden tinge. That is probably because the spirit has not spent long in cask.

Nosing the sample brings notes of grapefruit, ripe banana and apricot. Once it has stood a while in the glass there are hints of oak, fried camembert, iron and light spice. The aromas hang on in the glass for a long time.
On the palate there are notes of forest and spruce to begin with, slightly musty, then it moves towards sweeter notes along the lines of plum, fig and cherry.

Overall a good dram that tastes of a very young spirit, which perhaps lacks a little depth compared with whiskies that have spent a long time in cask. Otherwise an interesting sample with good potential if it were allowed to sit longer in cask.

The second sample is at 44% alcohol (Brettanomyces fermented whisky 006). The first sample was made with Saccharomyces cerevisiae (SC), an efficient, fast yeast that gives a high yield and can ferment in just a few days. That is why it is widely used in the whisky trade today, especially at distilleries with large production. A "contrast" to that yeast is Brettanomyces (B), which is slow to ferment and can take several months, unlike SC which took just a few days. That is the yeast sample number two is made with. "B" adds earthy, leathery and smoky aromas to the distillate. Besides the slow fermentation process, this yeast is also difficult to work with, as it can easily create unintended flavour aromas and cause cross-contamination between batches. So it has to be handled with great care, and together with the slow fermentation that makes the whisky expensive compared with using SC yeast. The yeast does allow you to create something unique, though, whisky that takes on the character of the time and environment it comes from. The yeast in this sample comes from blackberries at Naestbyhoved Castle on Funen, and this strain is said to give notes of mango and pepper. This distillate has rested with staves that held cognac, mirabelle brandy and bourbon, which have given flavour and aroma from those.

My notes are as follows:
The colour is exactly the same as the first sample, very pale and transparent. Again a sign that it may not have matured for long in cask.

The sample smells of forest on a rainy day, chutney and pickled gherkin, otherwise it has tart notes along the lines of grapefruit or sour sweets. After some time in the glass there are also notes of mash and an addition of sweetness.

On the palate there are clear notes of wood and oak, pepper, and a little forest floor and earth. The finish does not change much and quietly fades out. Like the first sample, some depth and finesse could probably be added if the whisky were allowed to mature longer in cask. Otherwise a very rounded spirit.

The third sample is at 42% alcohol and is made with the same yeast as the first, so SC, which is also said to have raspberry and cherry aromas. The difference from the first is that here the barley grains were given smoke over four days from birch and cherry wood, which should add some depth in the form of smoke. Otherwise exactly the same yeast, process and staves used in maturation.

My notes are as follows:
Again the colour is just like the other two, so no difference there. There is a marked difference in the nose, though, as this sample offers notes of a fireplace and cosiness in a mild version without getting too smoky. Otherwise notes of apple blossom, deciduous forest and very little spruce. After some time in the glass the nose is reminiscent of a fire burning down.

On the palate the sample feels a little watery to begin with, then a mild smoky flavour comes through and quietly rises in intensity without getting as smoky as you know it from typical Islay whiskies. This sample has more character than the first two, and otherwise a good roundness that could probably develop even further with longer cask maturation.

The fourth sample is at 42% alcohol and differs a little from the others, as this one is made with "spontaneous fermentation" and goes back to earlier days when you used the microbes around you and could not control the fermentation and distillation the way today's tools allow. Nor could you control the environment you were brewing in, and you had to gamble somewhat on natural yeast cells and bacteria being present to turn the sugar into alcohol. It was a bit less controllable than today's cultivated yeast cells, which are far more consistent in their properties and behaviour. That spontaneous fermentation is what this sample is based on, and like the yeast type in sample two, the process takes several months rather than several days. Here the mash was left standing outdoors, where the natural yeast cells and bacteria in the environment slowly finished the fermentation. The batch this sample comes from is spring 2023.

Like sample 2, this distillate has had staves soaked in cognac, mirabelle brandy and bourbon, which have given flavour and aroma from those.

(should have aromas of: green apple, wild flowers, earthy sour undertones?)

My notes are as follows:
The colour does not differ from the first three. The nose, on the other hand, is very particular and most of all resembles the smell of vinegar from the kitchen. That aroma is very pronounced and it is hard to find other notes behind it. Exactly the same vinegar notes come through on the palate, and it feels a little watery. It prickles slightly on the tongue, and again it is hard to find notes you otherwise know from classic whisky. It is a very unusual tasting experience, and perhaps a good example of why this yeast type is difficult to work with.

If this piece has not scared you off entirely and you are more interested in what yeast means for whisky, you should contact Claus directly at Scientific & Lectures, as he offers courses and lectures on everything I have touched on above. Alternatively you can join his masterclass at Whiskymessen 2025