We recently visited Three Sheets to chat with Max Venning about Linden Leaf’s new Cocktail Elements garnish atomisers (read our review here). We were suitably excited by what we discovered and decided to have a more in-depth chat with Linden Leaf co-founder, Matthew Webster, to find out more about the company and its products.

How did the Linden Leaf Project come into being?

Linden Leaf was born out of our collective obsession with flavour and our scientific understanding of flavour extraction. We are all scientists and big foodies. We were talking one night over dinner about molecular flavour extraction techniques and how the distillation process for spirits has barely changed in almost 150 years. Some of the traditional distillation processes struggle to retain all of the flavours you’d want or extracts too much of the flavours you don’t. It’s challenging to bring the top notes across which can be nice but also harsh. If you compare this to the perfume industry, where they are able to extract the exact scents they want including those more delicate and ethereal smells it felt like the spirits world was missing a trick.

So we rented a space in Cambridge, used an array of modern techniques that extracted the flavours and separated out the individual flavour molecules we wanted, and then did a lot of analysis and testing.

We tend to work out something that we really like personally flavour-wise and then through the tasting and flavour modelling make sure that there isn’t an outlying set of people that don’t like it. Take fresh coriander, for example. It has the most amazing flavour and scent; it’s beautiful. Take a sniff and it’s almost as if you’ve just opened your windows onto a freshly cut meadow below. That scent can make the hairs spike up on your neck, it’s so potent. Yet some people can find it quite bitter. It turns out that the fresh zingyness of coriander can be made using a handful of other natural molecules that people don’t find bitter.

And then there’s the scenario where some people thought the tail end of one of the gins was a bit too spicy, but we are able to fix this by tweaking the extraction of the pepper that we were using. We could essentially keep all of the flavour characteristics but get rid of that hint of spiciness that some people didn’t like, which, from our perspective, wasn’t really a key part of the flavour anyway.

We did thousands and thousands of these tastings and started to map flavour preferences at a molecular level to create the perfect expression of different botanicals. It started as a passion project and quickly became a business.

What are your general ethos/values/goals?

Flavour first – Whatever we create must represent the pinnacle of flavour and maintain the smell of the raw ingredients.

All natural – We’re passionate foodies and have no interest in synthetic flavours. Everything for us must be all natural. Trying to recreate in a lab a flavour that smells of lime, for example, holds no interest for us.

Sustainability –We care a lot about sustainability and always consider ways to reduce waste, cut down on food miles, and close the loop to ensure all aspects of a fruit can be put to productive use.

Organic – We only use organic produce, which feeds into our flavour first philosophy as organic producers tend to be a lot more committed to what they’re making and a lot more flavour driven.

The principal thing that drew all three of us to using organic produce when we’re cooking is that it tends to taste better and tends to be much better for the environment in terms of how it’s grown and how it’s produced. The supply chain also tends to be better because every element of it has to meet standards, both of quality and hygiene, and also, how can I put it, the moral behaviour in terms of what happens. On the other hand, everything becomes about 10 times harder when you’re organic. So there are downsides…

What are your backgrounds?

All three of us have very detailed scientific backgrounds and are all involved in molecular analysis. There are relatively few people with this sort of background in the spirits world, so we tend to look at things from a different perspective than most and do things differently as a result.

I’ve been writing software commercially since I was 15 and I have an astrophysics PhD from Cambridge. I’ve worked in mathematical modelling and startups and I’m also a passionate cook and avid collector of wines and spirits.

Mukund also has a PhD in astrophysics from Cambridge, where we first met. He’s ridiculously clever and a little bit of a nerd – he knows everything about everything, speaks umpteen languages, and is obsessive about flavour and smells.

Paul comes from a chemical engineering background. He was a  go-to trouble shooter in the petrochemical industry — if there was a tricky problem no one could solve, he was your man. He’s also a massively dedicated and ambitious cook; everything he prepares is time intensive and very elaborate, and whatever he prepares you can be sure it’s been marinated, stuffed, or rubbed for days.

Tell us about how your spirits are made (feel free to go in depth)?

Although the best human noses are incredible analytical instruments they struggle to pick out every note in a complex mixture. They also cannot tell you what exact molecule is responsible for each smell. However, we found there is a way to turbocharge the human nose.

Gas chromatography (GC) is a laboratory technique for separating a mixture into all of its components. You evaporate a tiny bit of your mixture and push it down a long, thin glass tube with a special coating, called a column. Different molecules move at different rates, so at the far end each type of molecule comes out at a different time. Usually, you put an electronic detector at the end, but we found you can also use a human nose. A patient sniffmaster’s nose can, miraculously, pick out the smells from even the tiny amounts coming through. So peaks can be labelled “lemon zest” or “lilacs”… or, sometimes, “horrible”.

Together with GC and our noses, there is an amazing bit of technology called a mass spectrometer (MS) which can help us work out exactly what molecules make each smell. This uses an electric charge and a powerful magnetic field to measure the mass of each molecule very precisely. You put one at the end of a GC to make a GC-MS and, as each separated type of molecule comes out, it tells you the mass and how much of it there is. It measures the mass so precisely that you can usually work out the exact structure of the molecule. By picking the right source of a particular botanical and then carefully tuning our extraction parameters, we can maximise the yield of the molecules we want. We can even make sure that subsequent batches are consistent: molecular craftsmanship.

Now, when it comes to extraction, we have looked at so many types of methods, from traditional hot distillation to cold distillation, infusion, and even supercritical CO₂. We use whichever method is most appropriate to the particular ingredient. The most common method is a highly tuned, chilled vacuum distillation. Using advanced laboratory equipment, we can reduce the pressure inside our still to just a tiny fraction of atmospheric pressure: much lower than the top of Mount Everest. This means even the most delicate ingredients can be extracted at very low temperature, avoiding heat damage. In almost every case, we extract each ingredient by itself, allowing us to tune the parameters to obtain exactly the notes we want. This means we can retain the just-cut scent of fresh ingredients: the invigorating zing of citrus zest, the cooling aroma of watermelon.

Like everything else, it’s horses for courses. As you increase the temperature, different flavours come out, and sometimes they’re what we want for the blend. For example, warm extracted liquorice and coffee have richer, deeper notes that are perfect for some blends.

To what percentage is your vodka rectified to and what is your grain mix?

We do not distill our own alcohol yet, but as our volumes grow we can see that happening in the future. Right now, we figure we are better off looking at the nuances of flavour science than bulk distillation, and there are many excellent manufacturers of high quality alcohol for spirits use. Despite being distilled six or more times, there is still an element of flavour to each product.

For each spirit we use, we work with commercial organic alcohol distillers to make mixed grain alcohols which have the flavour profiles we want. The grain mix ends up being slightly different each time: we taste and analyse and blend for each batch. We get the alcohol from them at 96% ABV.

With our vodka, we did a lot of research into how alcohol and water molecules interact. We had always suspected there was some mechanism behind the huge variety of mouthfeels in different vodkas, and it was good to understand the underlying processes. It turns out that with the right alcohol and the right water – if you control the filtering and mixing process very exactly in terms of temperature and rates – then you can create a silky smooth mouthfeel. Singularity is bottled at 45% ABV because that’s where we think it tastes best.

Tell us why you decided to create Cocktail Elements? What was important to you in its development?

The idea for Cocktail Elements, like everything we do, was inspired by flavour. There is a real variation of flavour from one citrus fruit to the other and from day to day, week to week, and season to season depending on where they come from, and this varying consistency of fresh fruit produce will then inevitably impact the flavour of your cocktail.

Then there’s the sustainability concerns of using fresh fruit, the wastage incurred, and sourcing things from out of season from the other side of the world. But the solution needed to be convenient and affordable for bars and consumers or it wouldn’t  work. We’d seen atomisers attempted before but they always seem to be oil-based, which to our mind fail on flavour. While these oil-based aromas can be intense and work well in food, the bitterness caused by just a few drops  in your martini leaves a bad taste. So we looked for a better way.

How do you make Cocktail Elements?

The extraction that we do at the beginning is done by pulling out the specific molecules and flavours that we want, which tend to be these top notes, these very light molecules. And then we put them out into an alcohol base in a chilled extraction where every aspect is minutely controlled – the size of the peel, the way it’s blended with the alcohol, the temperature of the alcohol, how long we let it macerate, the pressure at which we let it macerate – because  if you let it macerate at too low of a pressure then all of the light molecules come off the top. We then do the extraction from there, and the whole extraction process is chilled and, again, minutely controlled so that we don’t lose any of the flavours and we bring these very light components across.

I mean, it’s a myriad of detail across all of this and it starts getting into proprietary stuff in terms of how we control the distillation and how we bottle and store the product, but what I can say is that we buy 150 kilos of limes, and these are top-end organic limes from brilliant growers. It costs us a fortune.

The Cocktail Elements concept is something that would work fantastically in bars. However, during COVID you are tackling the home bartender first. How do you aim to educate/inspire the possibly nervous or sceptical home user?

We believe consumers care more about organic, sustainable produce than some give them credit for. But, even putting that aside, Cocktail Elements is simple and convenient. How many times have you fancied a G&T but not had a fresh lime at hand to garnish, or gone to make an Old Fashioned and are missing an orange peel or only have one that’s sat in the fridge and looks well past its best? People have really upped their home cocktail game, especially since lockdown, and are more open to preparing more drinks at home — both simple serves and cocktails. Cocktail Elements provides a really convenient, expert finish to a drink, and you will really be able to taste the difference.

We’re expecting this will be a pretty popular stocking filler or secret Santa this Christmas for cocktail lovers and foodies that love flavour.

Your Cocoa and Coffee Single Note bottling are astonishing. Can you please tell us a bit more about these?

It’s like everything else we do. We start by looking at producers who share our values: organic producers who really love what they do and are proud of their products. Then we taste and taste some more until we can find ingredients that will deliver an amazing flavour profile.

With Arabica, our coffee spirit, the organic, fair trade coffee comes from Peru, where it is grown by Isaias Rivera Cruz and his family. The farm lies in the Cajamarca region in the district of La Coipa, and H R Higgins sourced the beans directly via the 121 Project. Most of the coffee cherries were picked in August when they were at their optimum level of maturation and sweetness. The cherries are processed at the farm using a traditional method of fermentation tanks and eco pulpers. The waste generated by the processing of the cherries is treated in oxidation tanks to avoid any contamination of water tables downstream.

We chose this coffee not only because of its excellent environmental credentials, but because of its extraordinary aroma and palate. Apricot and orange bright notes complement a rich, dark flavour arc, and the complexity makes it particularly suitable to molecular extraction. By carefully tuning our process, we pull out the full range of flavours and aromas.

With Criollo, our chocolate spirit, we tasted hundreds of different varieties before we finally selected Le Chocolaterie Robert in Madagascar. They’re regularly rated as one of the best fine chocolate makers in the world, with prizes like the Cabosse d’Or and gold medals from the Academy of Chocolate. We use a rare Criollo-Trinitario cacao grown in the Sambarino organic rainforest plantation in northern Madagascar. It’s incredible stuff and the smell when we are extracting it is heavenly.

Both the producers we use for the cacao and coffee are organic, specialist producers, so it takes a while to get additional stock from them. We weren’t anticipating the popularity the first time, but this time we have a lot more of the raw ingredients, so stock should no longer be an issue. The coffee is already back on the website and the cacao is coming in the next few weeks, as soon a production time allows us to do the bottling.

Would you ever consider pre-batched cocktails using your spirits and methods?

Now there’s an idea…

What’s next?

We’re always experimenting with our exploration range and using our years of research and catalogue of organic flavour to develop new, innovative expressions. Watch this space.