Who’s Afraid of Heads, Hearts, and Tails (vintage)?


Heads, hearts, and tails. Three simple words. But they inspire awe and fear in the hearts of many beginning distillers. Should we be afraid of heads, hearts, and tails? This iStill Blog post aims to answer that question in a few simple steps.

First, let’s investigate what heads, hearts, and tails are. Then, we’ll research their properties. As a third step, let us assess why heads, hearts, and tails are important – and often awe-inspiring. The final part of this blog post will propose a framework for you to manage heads, hearts, and tails cuts.

Heads, Hearts, and Tails: what are they?

Not al alcohol is ethanol and not all alcohol is created equal. Where ethanol is intoxicating without being toxic, when consumed in moderate amounts, some other alcohols are actually quite toxic, even when consumed in very limited amounts.

During distillation – especially in the lower power-input and higher-proof finishing runs – the good alcohol we call ethanol comes over in the middle, during the “heart” of the run. The other alcohols, with high toxicity, come over at the beginning and end of the finishing run. The first part of the run is therefor called “heads”, while the last part is named “tails”.

So basically heads and tails are phases during the distillation run, when overly toxic alcohols come over. Does it start to make sense why they are fear-inducing? Cut too many heads and tails into your hearts and you end up with a toxic spirit.

Okay, the bad news is that heads and tails are really bad. The good news is that they only come over in the beginning and at the end of the run, and the actual amounts are small. But what are their properties? Let’s dive in deeper.

Heads, Hearts, and Tails: what are their properties?

Scientifically, a better name for “heads” is “lower boiling point alcohols”. The alcohols with low boiling points come over early in the run. Think aceton or methanol. A better name for “tails” is “high boiling point alcohols”. Propanol, butanol, and furfural come over late in the run, because they boil off at very high temperatures. Higher than ethanol, and sometimes higher than water.

In general, low boiling point alcohols cause head-aches. High boiling point alcohols create stomach problems. Mnemonic? Heads give head-aches, where tails create tail-end issues.

Floral and fruity flavors come over during the first part of the distillation run. Floral and fruity flavors associate with heads. Rooty, nutty, and earthy flavors come over during the last part of the run and associate with tails. Do you feel a catch 22 coming? Here it is. If you want to cut out all heads, you’ll cut out all floral and fruity flavors as well. Do you want to get rid of tails? Great, stills (or run procedures) can do that for you. But you’ll loose all rooty, nutty, and earthy flavors as well.

Why are heads, hearts, and tails important – and awe-inspiring?

Cut in too many heads and you end up with a spirit that causes head-aches. Cut out too many heads and you end up with a spirit that lost its floral and fruity flavors. Idem for tails. Do you start to see why cutting for heads, hearts, and tails is important – and awe-inspiring at the same time? Good cuts make great product. Poor cuts destroy your product. In a way a good distiller is someone that knows how to make great cuts. In a way a great still is a machine that controls the cut-points for heads, hearts, and tails to perfection. In a way distilling comes down to cutting.

So far, the industry has seen two approaches on how to deal with this issue. Big Alcohol has often been accused to just cut everything in. It explains the morning-afters. It makes for a good amount of profit, since the manufacturer doesn’t have to cut out anything and all alcohols produced end up in a bottle. A bottle being sold to you.

The second school of thought, that started with the birth of craft distillation, aimed to cut out heads and tails all-together. The result? You can guess it, right? Uninteresting spirits.

Our insight, based on science, brought a third way of looking at heads, hearts, and tails to the forefront: the one we shared above, where heads, hearts, and tails have both positive and negative properties. It’s not about cutting them in or out, it is about the flavor profile you want to high-light as a distiller, when producing a certain spirit!

A Framework for Managing Heads, Hearts, and Tails

First, decide what spirit you want to make and what the associated flavor profile is. Some examples? Here you go. Vodka aims for a minimal flavor experience at high purity, so you’ll want to cut out all heads and all tails. Less flavor, more purity, less toxicity. Whisky is flavorful and full bodied. Incorporate late heads and early tails, and only cut out the early heads and late tails. You’ll get all the flavor, while controlling – to an extend – overall toxicity levels. Fruit brandy? Fruity flavors are found in the heads, so cut out all the tails, and cut out only the very first bit of the heads.

Secondly, choose the right type of still. A potstill sucks at compacting heads and tails … and is therefor a great tool for whisky making, where you need both the late heads and early tails to smear into hearts. Bubble cap stills offer great defense against tails smearing, which makes them very well suited for fruit brandy production. iStills, with their elaborate control systems and automated cuts management, can make any spirit to perfection.

Thirdly, please understand that low and high boiling point alcohols (and their associated flavors) are developed during fermentation, not during distillation. Distillation is simply a way to control them. In other words: if you want to create a certain flavor profile, for a certain product, with a certain still, well, it actually all starts with your fermentation protocols! If you ferment in such a way that no flavors and no toxic alcohols are formed, you are already almost at vodka level purity, even before starting-up your still. That is great if vodka was your goal, but not so good when making whisky. The opposite holds true as well: a flavorful ferment is a great base for whisky making, but not for vodka production.

The fourth step should actually be the first step. Learn more about still design, about spirit flavor profiles, about how fermentation influences heads, hearts, and tails production. Learn more about cuts. Where? At the iStill Distilling University. For more information and registration, contact Veronika@iStillmail.com.


The Right Attitude to Distilling at Altitude!


More consultant-baloney that needs to be addressed. I read an article that “researched” distilling at altitude. The consultant’s conclusion was that craft distillers located at higher altitudes have the amazing benefit of “gentler boils”. And the article implied that these craft distillers have a benefit to others, located closer to sea level, as these low-altitude distilleries are confronted with more aggressive boils in their stills.

Now, everyone is entitled to their own opinion. But no one is entitled to their own facts. The right attitude to distilling at altitude is not based on an opinion, but on science. Science perfectly explains how distilling at altitude differs from distilling at sea level. Spoiler alert: the consultant that claims high-altitude distilling is favored by a more gentle boil in his still is completely wrong. Science teaches us it is the exact opposite.

Air pressure

The earth is surrounded by a layer of air. This air asserts a pressure downward, on the earths crust. Or on the people, distilleries, and stills on that crust. A lower location results in a bigger layer of air above your distillery. A bigger layer of air above your “lowland” distillery results in high air pressure.

A distillery that’s located at 2,000 meters or 6,000 feet could be called a “highland” distillery, or a “distillery at altitude”. The layer of air above this location is smaller, resulting in lower air pressures at these higher altitude distilleries. Why is this important? Because air pressure is one-on-one related to boiling temperature.

Pure ethanol boils at 78.3 Celsius. At sea level, that is. In Utah and Colorado, visiting distilleries at altitudes of 2,000 meters and more, I have seen boiling points drop to as low as 72 degrees Celsius. How come that high-altitude distilleries are faced with lower boiling points of pure ethanol? Because there is less air pressure.

A boiling liquid uses all the energy input to form gasses. The bigger the air blanket, the higher the air pressure, the more back-pressure those gasses are met with. Higher pressure, including higher air pressure, results in higher boiling points of the liquid that generates the gasses. Contrary, at high altitude, in a low air pressure situation, gasses are not pushed back as hard. They find less resistance and the boil starts earlier because of it.

Slightly more scientifically?

Liquid boils in order to remove a surplus of energy that is introduced in the system. The way the substance can cope with the surplus is by getting molecules in a gaseous phase. The bigger the air blanket, the higher the air pressure, the higher the vapor pressure is, resulting in higher boiling points of the liquid that generates the vapor. Contrary, at high altitude, in a low air pressure situation, vapors are not pushed back as hard. They find less resistance and the boil starts at a lower temperature because of it.

Gentle boil, really?

As air pressure creates “resistance” to the boil, it slows down both the boil and the vapor speeds of the resulting gasses. More air pressure equals a slower boil and slower vapor speeds in the column. Less air pressure results in less resistance in the column, and thus in a more aggressive boil!

There you have it: the consultant was wrong. Completely wrong. And there is a risk that many craft distillers read his article and thought they needed to be afraid of not being high up in the mountains. They shouldn’t be afraid. It is 180 degrees different from how the consultant presented his conclusions. It is the sea level distilleries that are faced with the gentler boils, because the higher air pressure dampens both the boil and the speeds of the gasses exiting the liquids because of that boil.

The right attitude

You distill in a location, because you live there. Or because you expect it to be a city full of commercial opportunities. But, please, don’t move up the mountain, because of this consultant’s completely wrong assessment that it would lead to more gentle boils, implying “better product”.

Here’s what is really going on, when we compare a sea level distillery to a high-altitude location. The high-altitude distillery is faced with a more aggressive boil and higher vapor speeds in his column. This results in more smearing of heads and tails into hearts. All things equal, a higher location results in less control and a more contaminated product, that needs more aging.

There is an additional disadvantage for high-altitude distilleries. Air pressure changes and their relative influence. Sea level distilleries have a big air blanket above them. If the air pressure changes (different weather fronts coming in, for example), it changes a little bit. For distilleries at altitude, even small changes are RELATIVELY bigger, resulting in more variability in vapor speeds and more variability in smearing and flavor (like the “bumping” issue in vacuum distillation, discussed in an earlier iStill Blog post).

How to manage altitude

In order to compensate for the lower air pressure at higher altitudes, the distiller needs to power down. A lower power input results in a less aggressive boil and lower associated vapor speeds. Sometimes as much as a 50% reduction in power is needed, but this obviously depends on still type, spirit, and location.

To compensate for the higher variability in vapor speeds, in distilleries at altitude, the distiller needs to invest in a still that has power management, air pressure sensors, and automated cuts management. Power management allows the distiller to compensate for low air pressure conditions. An air pressure sensor can detect changes in air pressure, a computer can translate these changes into new cut point temperatures, and an automated cuts selector can translate these outcomes into perfect cuts, each and every time.

Hmmm … if only there were such a still. A still with 1-100% power management. A still with seven digit accurate air pressure measurements on a per second basis. If only there is a still with a computer and software to translate air pressure changes into new cut points, instantly and automatically … wouldn’t that be an amazing innovation? If only …

iStill’s air pressure sensor measures every second with seven digit accuracy …


Laboratory Verdict: iStill Whisky …


Today, we present more laboratory findings. We compare a craft distilled whisky, made on an iStill, to the world’s most popular Bourbon, Jim Beam, and to the so-called “Rolls Royce of single malts”, aka MacAllan’s. Jim Beam is made on an industrial level, using continuous distillation, and bubble-cap technology. The MacAllan is batch produced, double distilled, and uses traditional copper potstills. The craft distilled whisky is small batch (2000 liter boiler capacity), is distilled 1.5 times in potstill style, and uses iStill’s modern hybrid distillation technology.

Even though this comparison could be about industry size, applied technology, and distillation procedure, we think there is a more important question to ask. Here it is: does whisky produced on an iStill outperform Big Alcohol’s most sold Bourbon and Big Alcohol’s most sought after single malt whisky?

In general, craft distilled spirits are more expensive to produce than big batch or industrial scale whiskies. For craft distillers to become successful, they need to make up for that by delivering on taste. A more tasteful and flavorful product compensates for the higher production price.

Again, as in the “Laboratory Verdict”-post from last week, we’ll use Odin’s Holy Trinity of Distillation Theory to make predictions of what to expect. Then we’ll present the outcomes of the laboratory study and confront these with the predictions. Finally, we’ll draw some conclusions for craft distillers to learn from. Advance notice & warning: you might just learn how to make the best whisky in the world.


The laboratory researches and compares the three whiskies on four categories:

  1. First dimensional, front-end intensity: fruity flavors;
  2. Second dimensional, middle-of-mouth intensity: grain flavors;
  3. Third dimensional, back-of-mouth intensity: rooty and nutty flavors;
  4. Maturation: is the spirit of age yet, or does it need more time to further develop and mellow out?

As the Jim Beam is a Bourbon, a whiskey with a first and second dimension only, we expect well-defined fruity and grain flavors, but no rooty and nutty flavors. The bubble-cap technology prevents any back-end smearing. Jim Beam is aged for 4 years, limiting the amount of heads smearing they can add. This Bourbon is fermented and distilled on the grain, which should boost the second dimensional grain flavors.

The MacAllan is aged for 12 years. This prolonged maturation time allows for more heads and tails smearing to be added to the hearts cut, as there is more time for them to mellow out into interesting front-end and back-end flavors. We expect the middle-of-mouth experience to be somewhat lacking, as MacAllan is not fermented nor distilled on the grain. Also, they use a short fermentation time, that hampers taste formation. Finally, chill filtration will eat away at the “size” of the third dimension.

The iStill whisky is fermented and distilled on the grain, and should therefore have an impressive second dimension. The modern process controls should result in an impressive first dimension. As the iStill combines a 1.5 distillation approach with direct heating, the Maillard Reaction is expected to give an impressive back-end, third dimensional flavor. The iStill whisky is only 3 1/2 years old and needs many more years of maturation.

First dimension: fruity flavors

The iStill whisky has the most fruity flavors, followed closely by the MacAllan. Jim Beam has significantly less of a first dimension, which is the result of their relatively short maturation period of 4 years. Both, the MacAllan and iStill whiskies can allow for more heads smearing as these products (are expected to) mature longer. Longer maturation turns a larger heads smearing into more interesting and complex flavors. Jim Beam, with the shorter maturation, simply needs to be more careful here.

Second dimension: grain flavors

iStill whisky has the most grain flavors, followed by Jim Beam. The MacAllan lacks here, because it does not ferment on the grain, does not distill on the grain, and uses relatively short fermentation times, that hamper flavor development. iStill delivers more grain flavors than Jim Beam because of a longer fermentation time and the lower total number of distillations, that leads to less flavor dilution.

Third dimension: rooty & nutty flavors

The iStill whisky’s back-end flavors benefit from the Maillard Reaction that results from its its unique 1.5 distillation protocol in combination with direct heating and on-the-grain distillation. It delivers a category-shattering record third dimension that is 5x bigger than MacAllen.

The Scottish single malt suffers, not just from a lack of tails smearing, but also from the chill filtration they apply. Chill filtration takes away a lot of the third dimension flavors, but allows the whisky to be bottled at lower strength, thus creating more product. Dilution of flavor and strength to sell more bottles? Doesn’t sound very “Rolls-Royce” to us.

The Jim Beam Bourbon, true to its category, and because of the use of bubble-cap trays, has no third dimension. The lack of the heavy hitting rooty and nutty flavors, allow the fruitiness of the Jim Beam, even with a smaller heads smearing, to shine through.


The MacAllan 12 y.o. is fully matured. In fact, it might have benefitted from a little more tails smearing and/or less chill filtration. More tails smearing would take advantage of the long maturation period by creating a more interesting single malt whisky. The Jim Beam Bourbon is well-matured, but could benefit from a few additional months or maturation. The iStill whisky is still very young and will only be fully matured at 8 y.o., so in about four years from now. During the next four years, as the iStill whisky matures, more first, second, and third dimension flavors will be created, further extending its already impressive lead in flavor.


The most important question we wanted to answer today, was this one: can whisky made with an iStill outperform Big Alcohol’s most sold Bourbon and its most sought after single malt whisky?

Based on the laboratory results, presented above, we can now answer that question with confidence:

  • Craft distillers can make more flavorful whisky than Big Alcohol;
  • When they use iStill technology, training, and procedures.

The science concludes that iStill produced, craft distilled whisky outperforms the most sold Bourbon and most revered single malt whisky. With just 4 additional years of maturation, the iStill whisky will most probably be the best in the world.

Now, what does that mean for the global whisky industry? We think that it means that, within a decade from now, iStillers will be making the best whiskies in the world. All over the world.

Do you want to learn how to make the best whisky in the world? Reach out to Veronika@iStillmail.com for more information on our courses. Do you want more information on our amazing stills, mashers, and fermenters? The machines that allow for ultimate process and flavor control? Please contact Esther@iStillmail.com. Do you want us to analyse your vodka, whisky, or rum, and come back with advise? Please order our laboratory services with Robert@iStillmail.com.

Backing it up with science …


“Terroir”: Thing or Fling?


Today’s topic? The importance of “terroir” to the craft distilling industry in general, and in whisky production specifically. What is “terroir”? How does it apply? Is it worth the attention it is currently getting? Is it a buzz word or is it simply the latest FUD word that consultants use to scare you into thinking you have an issue that needs to be resolved, preferably with their help?

Underneath, I’ll explain in depth what “terroir” is, how – if at all – it is applicable to craft distillers, and I’ll come up with an easy model that allows you to decide if it is something you have or should aspire to have. Let’s dive in deeper.

What is “terroir”?

“Terroir” refers to soils, on different locations, having different properties. And those properties influence the crop that grows there. Mineral content, moisture, wind, etc. make that the crop that’s grown at a specific location is bigger, smaller, or maybe even tastier than that same crop grown on another location. Another location with different properties results in different flavor profiles and therefore, if we use what’s grown on that location to make spirits, in differences in spirit quality. That’s what consultants try to sell you, at least.

“Terroir” comes from France. It is used in the wine industry. Is it important to the wine industry? It is. Here’s why. There are many varieties of grapes and there are many, many vineyards. All grapes have specific flavors and all locations have different hours of sun, rain, wind, and more. Grape production – at least for the wine industry – is both localized and compartmentalized. Many very small stretches of land with many different properties result in many different wines. The best wines come from great wine-makers and the “terroir” of where they make the wine must be a very good one. Better “Terroir” basically means that one location is a better place to make better wine relative to another location.

Just to be clear, “terroir” is not about Napa Valley wines being different from Burgundy wines. “Terroir” is about one small vineyard in Burgundy, in a specific city, on a specific hill, having a slightly different climate and soil composition than its neighbor. It is about my hectare of vines being different from your 0.8 hectares. We are talking micro here. Really micro.

Why “terroir” is of no importance to most craft distillers

There are two main reasons why “terroir” does not apply to most craft distillers that make whisky. First of all, grain is a commodity. It is grown on big, very big patches of land with the aim not to diversify flavors, but to maximize yield. Contrary to winemakers AKA grape growers, grain growers do not intently look for different, specific flavors. Grain yields carbohydrates and flavor is a byproduct. Contrary to vineyards, that produce specialty products, grain farming is about the mass-production of a commodity product. All grains, from a certain variety basically taste the same.

So craft distillers cannot claim “terroir” for their grain-based drinks, but how about brandy? Brandy is made from wine and wine has “terroir”, so brandy could have “terroir”, right? Well, it could, but it doesn’t. Distilling a specific wine of great “terroir” taught us that it couldn’t be reproduced in the brandy. In fact, great wines result in poor brandies. A brandy made from Petrus or Margaux wines is pretty unimpressive, as we established, where cheap wines from both Germany and France delivered excellent results.

What makes the difference, if not “terroir”? Higher proof wines result in lower flavor brandies, where lower proof wines result in high flavor-intensity brandies. The cheap 9 and 11% wines resulted in more flavor concentration than the 13 and 14% high-end wines. Did the amazing “terroir” of the high-end Petrus and Margaux shine through? No, not at all. Like as if it never existed in the first place. And that’s the second reason why “terroir” does not apply.

There you have it: consultants and craft distillers talking about “terroir” are like the emperor’s new clothes. There are no new clothes. “Terroir”, in 98% of the cases, is complete BS, too often used by the consultant to get into your wallet. They want to consult with you so that you do not miss out on today’s “opportunity”, today’s fling. It is not an opportunity for most, so please miss out.

We also see “terroir” being used by some craft distillers, that want to sell their inconsistencies as something good or intentional, instead of as the lack of craftsmanship it actually is. To those I say: get some proper training and purchase some proper equipment and try to produce some consistent quality drinks. Consistency is the precursor to quality. Inconsistency does not equal a claim to “terroir”, it usually just signals minimal process control.

Side note: how many craft BREWERS do you know that claim “terroir”?

The exceptions to the rule

Let’s be very clear: some craft distillers CAN claim “terroir”. Here are the ones that I think can:

  1. Those that grow their own grain;
  2. Those that purchase their grain locally;
  3. Those that work with specialty grains.

Drentsche Schans Distillery and Wieke Distillers from the Netherlands, and Distillerie de Soligny from France are three great examples of craft distillers that have “terroir”. All three distilleries are farms that grow their own grains. These grains, and these grains only, are used for their whiskies. As the specific location consistently plays a role, as they actually use their “terroir”, they can claim to have “terroir”, where most others cannot.

Aristides Distillery from Cyprus uses locally grown Cypriot barley only, in their whisky. They use the “terroir” of Cyprus and are a great example of the second category that can claim “terroir”.

Wood Hat Spirits, from Missouri, USA, grows specific varieties of white, blue, and red native American corn. His whiskies have “terroir”, because this distillery only works with very specific grains that are even grown in-house, so locally. Dornoch Distillery, from Scotland, is another great example. They use older styles of barley, that have less focus on yield and deliver lower fermented ABV and higher flavor concentration.


I love craft distilled whiskies. Even though most have no claim to “terroir”, some craft distilled products are just fabulous. And so are some of the craft distilled products that can actually claim “terroir”.

The above iStill Blog post is not a rant against or in favor of “terroir”, and those that possess it or those that don’t. It is a rant against a new fake topic that I read too much about nowadays. It is not something anyone of you should be worried about. It is not something you should aspire to or miss out on. A specialty grain fits your story or it doesn’t. You know best. You do grow your own grains or you don’t. And maybe you don’t, but your barrel aging is amazing. Or maybe your Whiskey Sour, that you serve in your bar, is unmatched.

Your whisky is about your choices and priorities, and that is what matters. That’s the real TERROIR each and every craft distiller, that produces its own whisky, can claim. And none of you need a consultant to help “explain” that.

Gary Hinegardner and his wood hat and amazing whiskey…


Laboratory Verdict: Bourbon vs. Single Malt!


Very exciting times! We have added the iStill Laboratory Services to our already impressive portfolio of products and services. Why? To help empower craft distillers all around the world. How? By providing them with scientific feedback on the drinks they produce. Feedback and advise on how to improve product quality. More and better information helps make better decisions. A better informed craft distiller is an empowered distiller.

Today we present the laboratory findings of a comparison of a Bourbon (Jim Beam) to a Scottish single malt whisky (MacAllan 12 year old). Not your cup of tea? We disagree. The analysis and advise we share underneath is as applicable to your whisky as it is to Jim Beam’s and MacAllan’s. If you want to beat them, all you need is a steeper learning curve. So stay with us … and stay focused … and learn. It will be worth your time.

What are we looking for? What do we expect to find? Well, in a very concise way, the very first thing we want to find out is how a regular Bourbon and single malt compare. But on a deeper level, much more is at stake. What? Well, how about Odin’s Holy Trinity of Distillation? What does this theory say about Bourbon and single malt whisky? And does the model survive scientific and laboratory scrutiny?

So, first, let’s dive into the Holy Trinity of Distillation a bit. Some understanding of how the model works is needed. Secondly, if we apply Odin’s theory, how do we expect Jim Beam and MacAllan to perform? We need to find out what the model predicts. Thirdly, we’ll present the laboratorium results. Let’s confront the lab results of the Bourbon and the single malt, and evaluate if the Holy Trinity of Distillation’s predictions were adequate.

Jim Beam Bourbon …

Odin’s Holy Trinity of Distillation

A summary. Less heads and tails smearing results in a lighter product, that highlights the flavors associated with the hearts cut. The flavors that are associated with the hearts cut are the base substrate. In a rum it is where you taste the molasses. In a whisky or Bourbon it is where you taste the grains the product is made from. The flavors hit you in the middle of your mouth. Above the tongue. From seconds 2 till 6 or 7 after taking a sip, wetting your entire mouth with it, and then swallowing the drink. Longer fermentation times and on the grain fermentation and distillation add to a more flavorful hearts section,

The heads smearing can be tasted in the front of ones mouth. Lips, point of tongue, and gum. The heads-associated flavors are fruity in nature and can be experienced in the very first second after taking a sip, wetting your entire mouth with it, and then swallowing it. More heads smearing leads to more fruity flavors in a drink. Less heads smearing, via a bigger heads cut, results in lower front of mouth flavor intensity.

The tails smearing is tasted at the back of your mouth and gradually transitions towards your throat. The tails-associated flavors hit you from seconds 7 till 15 or 20 or even 25. More tails smearing results in a higher and longer lasting back-end flavor.

As 30% of flavor associates with heads and 50% with tails, heads and tails smearing are tremendously important for a drink. More smearing equals more flavor, but also means more aging is needed to mellow all those flavors out.

How a student of the iStill University put it …

Applying Odin’s theory on Bourbon and single malt

A single malt whisky is a three-dimensional product, that has a front, a middle, and a back-end. As the MacAllan has seen a much longer maturation time than the Jim Beam, we expect the whisky to have more heads and tails smearing. The bigger amount of smearing allows the MacAllan to take advantage of 12 years of barrel aging. More flavor equals more time to develop those flavors into something coherent and enjoyable.

Bourbon, in general, is a two-dimensional drink. It has a front and a middle, but not much (if any at all) of a back-end. This is the result of the applied distillation technology, that uses bubble-cap trays in the (continuous) columns. Bubble-cap trays are invented to effectively prevent tails smearing in fruit brandies. It is an 1870 innovation that gained wide traction in American whiskey distillation, because it allows for multiple distillation cycles to be performed in one go. The gained efficiency comes at the loss of the third dimension, to the extend that this absence now is an inherent characteristic of almost all Bourbons.

So, we expect the Bourbon to be relatively fruitier, as the front-end flavors make up more of the total flavor profile. Heads smearing attributes 30% of flavor, hearts just 20%, and tails as much as 50%. An expected absence of tails makes the Bourbon the lighter, sweeter, and fruitier product. The MacAllan is made on a traditional potstill. An old technology that is great at smearing heads and tails into the hearts cut. So, again, we expect the MacAllan to have a bigger first and third dimension than the Jim Beam.

But how about hearts? Hearts flavors contribute about 20% to the overall flavor profile, but who will win here? We expect the Jim Beam to outperform the MacAllan. Why? Because Jim Beam ferments on the grain and does the first distillation run also on the grain. More substrate contact during fermentation and distillation results in a tastier, fuller-bodied middle-flavor profile. MacAllan ferments and distills off the grain, so Odin’s Holy Trinity of Distillation predicts a lower flavor-count for the Scottish whisky’s middle.

MacAllan 12 year old single malt whisky …

Laboratorium results

As predicted by the model, the MacAllan has a more flavorful first dimension. Jim Beam hits the market after four years of barrel maturation. They make a tighter hearts cut with less heads smearing, simply because there isn’t enough time for a bigger heads smearing to mellow out. The MacAllan hits the market after over a decade. There is much more time for the bigger amount of heads smearing to mellow out over time. Put differently: MacAllan takes advantage of its prolonged maturation time via the incorporation of more heads, resulting in a bigger overall flavor profile, at least at the front. Jim Beam applies a similar flavor maximization strategy: given the limited amount of maturation time of four instead of 12 years, they still achieve an impressive result of about 60% of front-end, fruity flavors of the MacAllan.

As predicted by the Holy Trinity of Distillation, the Jim Beam has more substrate-related flavors. The fact that Jim Beam ferments and distills on the grain results in a 15% more flavorful second dimension than MacAllan has to offer. MacAllan lags behind on substrate flavors, because of the off the grain and short fermentation and distillation protocols.

Wow! The Bourbon basically has no back-end flavors. It is a two-dimensional product indeed. The MacAllan has a back-end and therefore a third flavor dimension. The outcomes depicted above are exactly as predicted by the Holy Trinity of Distillation.

Overall, we see that the front-end, sweet, and fruity flavors are more important in the overall flavor profile of the Jim Beam Bourbon. At the same time, we can learn that this generic Bourbon characteristic is more the result of the absence of those dominant back-end flavors than that it stems from a lot of heads smearing.

Advise to Jim Beam and MacAllan

What advise could we give to Jim Beam and MacAllan? In order to improve their whiskies? Not part of the lab results that we presented above, but the MacAllan is a fully matured product. Longer aging does not add anything. As MacAllan bases all of their whiskies on one and the same New Make, we expect that older varieties, like their 15, 20 and 25 year old products, primarily differ via specific cask finishes. The aging itself, above 12 years, seems to be more of a marketing or financial decision than that it is the result of the base drink needing further aging. Again, the spirit itself does not need more aging. Put differently: longer aging does not add anything, but might risk older MacAllan whiskies to loose their front-end due to oxidation.

Could we improve on the MacAllan? Yes we could. And – even though it is never going to happen – so could MacAllan. Where they can improve? Well, the middle of mouth flavors lack body. If MacAllan was an iStill customer, and if they weren’t all caught up in tradition, but open to innovation, we’d advise them to consider on the grain fermentation and distillation. It would put the flavor intensity of their second dimension above Jim Beam, and would bring grain flavors up, thus creating a better balance between the impressive front and the sorta adequate back-end.

Since Scottish single malt is usually fermented and distilled off the grain, there is another solution MacAllan could apply in order to strengthen the weak second dimension while staying true to tradition. MacAllen could return to a 5-day fermentation schedule, instead of the 3-day they have been using for some time. The longer fermentation would probably push the substrate flavors to about 2,000. Of course, it would come at the cost of an overall production output loss of around 40%. As single malts keep on being highly sought after, we do not see that happen any time soon. But be aware: this does open up a window of opportunity for craft distillers that now can quite easily outcompete Big Alcohol single malt production on flavor!

For the rest, we’d advise MacAllan to differentiate their New Makes and allow for more tails smearing in those New Makes that will become their 15, 20 and 25 year old products. More tails smearing will create a more interesting flavor profile that better distinguishes the more expensive and older whiskies from their 12 year old offering. Even the 12 year old might actually benefit from a little bit of additional tails smearing …

The Jim Beam that we tested was well-matured but not fully-matured. Our laboratory estimates that an additional 3 to 6 months would create a slightly smoother taste experience. We’d advise Jim Beam, if they were our customer, to take advantage of the little bit of additional, and thus far unlocked, potential of its Bourbon whiskey by giving it a few more months of rest. But on the other hand, we understand that commercially it is probably not worth it, to wait longer or to even have the labels changed to stating that they now age for 4 1/2 years instead of just 4.

Jim Beam’s market entry delivers where a Bourbon needs to deliver: in the first and second flavor dimensions. We expect their older varieties, like the Jim Beam Signature Craft, which is aged for 12 years, to contain a little more heads and even some additional tails smearing, but haven’t tested that yet. More heads and tails smearing would easily stand up to the robust middle flavors, that Jim Beam already delivers on, and make for a more interesting product, with a longer lasting taste sensation.

Some conclusions for you, the craft distiller

Since you, the readers of this iStill Blog post, probably aren’t the owners of, or distillers at, Jim Beam or MacAllan, what is your take-away? How does this information help you? Well, first of all, you now know scientifically what distinguishes a Bourbon from a Scottish single malt whisky. Secondly, we challenge you to buy a few bottles and start training your taste buds according to Odin’s model. Compare the Jim Beam to the MacAllan yourself, and taste the science we have presented here first hand. After that? Maybe buy a Pappy van Winkle and see how you’d score that on each of the three dimensions.

But there is more. All of you that studied at the iStill University now know that the models we trained you in are more than an amazing toolkit for the craft distiller to work with. Our models and theories are the only toolkit for the craft distiller to work with, since they are now proven scientifically. And that is not an opinion, but a fact.

What this means to you and to the craft distilling industry at large? That we have taken the guessing out of distilling. Finally and definitely and overwhelmingly so! Put slightly differently, it means the following: if you want to become a craft distiller, your future starts with taking the courses the iStill University offers. Interested? You should be. Please reach out to Veronika@iStillmail.com for more information. Why? If that is still a question on your mind, let’s summarize …

iStill – and nobody else! – trains you so that you can make better products. And not in the sense of “I think this is better” or “I actually enjoy this drink”, but with scientific proof that factually confirms that it is better and why it is better. Not an opinion. Not science fiction. Simply science fact.

iStill – and nobody else! – helps you design spirits that are better than anything other companies or consultants can deliver. That is no longer an opinion, but now a scientific fact. We are the only ones to apply science to improve your spirits in a manner that is objectively measurable and verifiable.

iStill technology – and nobody else’s! – makes the best spirits. That is not just an opinion, but now a scientifically proven fact.

Hold on … what? Wasn’t this iStill Blog post about scientifically and chemically comparing and evaluating a Bourbon and a single malt whisky? Yes, it was. But hold on to your seats as well as your pants: we also tested whisky made on an iStill. We’ll publish the results next week, but allow us to break the news to you here: iStill-made whisky blows anything else out of the water!

Do you want to test your whisky? Do you want our scientific advise on how to further improve it? Do you want to implement our recommendations and scientifically proof to your customers that your drinks are better than those of Big Alcohol? Under secrecy, yes, of course. Then please reach out to Robert@iStillmail.com and order the iStill Laboratory Services.


Bubble-Cap Stills Suck at Making Whisky (vintage)!


There, I said it. I have long considered not writing this post, but the misinformation about this topic affects the craft distilling industry negatively. That needs to be amended. Sure, statements like this will make me some haters, but hopefully that will be compensated by more craft distillers now being able to make better choices. And more importantly: better whiskies.

In this iStill Blog post, I’ll first investigate what a whisky is, and what its flavor profile should be like. Then, I’ll dive into the bubble-cap still design and elaborate on its pro’s and cons. Finally, I’ll explain how the bubble-cap still design prevents the craft distiller from making great whisky.

What’s whisky?

“Whisky is a distilled spirit, made from grain, where one – while drinking it – can identify the grain the whisky is made from”. Don’t you just love the above definition? It so clearly explains everything a whisky needs to be. Made from grain. And with the flavor profile intense enough to allow the drinker to establish the exact grain base. A spicy whisky? Probably rye. A sweet kinda whisky? Corn, so maybe a Bourbon. A mellow whisky? That must be a whisky made from wheat. A complex, full bodied whisky? I am putting my money on malted barley as its grain source.

Grain flavor profiles – and therefore whisky – are quite unique in that they offer front-of-mouth, middle-of-mouth, and back-of-mouth flavors. The floral and fruity flavors can be distinguished in the first second, where heads blend into hearts. The generic grain flavor hits you in the middle of the hearts cut, right after the headsy flavors subsided. The long finish reveals the tails-associated earthy, rooty, and nutty flavors. It is this long finish that is essential to whisky; essential to bringing out not only a long-lasting taste experience, but also the flavor identifiers for the grain bill.

What are the design pro’s and cons of a bubble-cap still?

A bubble-cap design is basically a potstill with two kinds of obstructions in the vapor path. First (from the perspective of the rising vapors), there are the plates with the bubble-caps on them. The gasses need to travel through them. Secondly, the vapors hit a cooler (that is often called a dephlagmator). The plates hamper the free flow of vapors. The cooler liquifies part of the vapors. The liquids fall back on the plates, creating a fixed liquid bath on ‘m. The gasses now have to almost fight their way upwards: through the plate, through the liquids, and through the cooler.

The benefits? Where a potstill can perform only one redistillation cycle, a bubble-cap plated still can perform multiple distillation cycles in one run. No more need for a stripping and finishing run! That’s great news. It helps with time and energy management.

The drawback? Those fixed liquid baths on top of the bubble-cap plates are tails traps. Now, mind you, this isn’t a drawback when producing fruit brandy. Fruit brandy focusses on heads associated flavors. For those fruity flavors to shine, tails smearing (with its heavier flavors) must be prevented. The bubble-cap still was invented for fruit brandy production. Bubble-cap stills offer a great defense against tails smearing. That was the real innovation they brought about, over a century and a half ago. Good for fruit brandy. Bad, really bad for whisky!

Why do bubble-cap stills suck at making whisky?

Bubble-cap stills suck at making whisky because they create two-dimensional spirits, drinks that high-light front-of-mouth and middle-of-mouth flavors. Whisky is (or should be) a three-dimensional drink, that offers a front, a middle, and (most importantly) a back-end.

Over 50% of the flavor is tails associated, is rooty, nutty, and earthy in make-up. It is that third and last dimension that makes or breaks a whisky. Try it. Drink some single malt. Wetten your mouth with a sip, then swallow. Keep your mouth closed. Now start counting. How long do you taste? Where do you taste it? A good fruit brandy is gone in seven seconds. A good whisky lasts and lingers in your throat for 15 to 25 seconds. The difference? Whisky has (or should have) a back-end, fruit brandy shouldn’t.

This is why bubble-cap stills suck at making whisky: they prevent the very flavors, that define any good whisky, from coming over into your spirit. The back-end flavors are trapped on the lower plates.

Now that you know it, you can make better purchasing decisions, when starting-up (or reconfiguring) your distillery. Do you want to learn more about stills design and how it can set you up for success or failure? The iStill Distilling University teaches you all there is to know about still design. For more information or course registration, please reach out to Veronika@iStillmail.com.

Bubble-cap plate …

Bubble-cap still …

iStill Laboratory!


We are starting a new service. We are starting the iStill Laboratory! The goal? To further empower the craft distilling industry. How and why? Let’s dive in deeper!

What’s craft distilling’s main USP?

Well, that’s easy. It is quality. Spirits quality. As craft distillers offer a story, an adventure to the consumer, it has to be a better story and a better adventure than Big Alcohol can serve. And that story or adventure always starts with the quality of the spirit served and the pride of the craft distiller that talks about his products.

Price? Not an issue. I mean, yes, it is a big issue, but it is out of the craft distiller’s control for a big part. In the competition with store bought products from Big Alcohol, craft distillers can never compete on price levels. Not even when using iStills. Big Alcohol simply has too much economy of scale behind its business model.

That’s why craft distillers need to focus on quality. If your products are going to be costlier to make than those of Big Alcohol, the only way to carve out a niche for yourself is via quality.

What is quality?

A difficult, yet not impossible question to answer. Those that studied at the iStill University might find it easier to answer than others, because of the models we teach. So, for craft distillers not yet versed in Odin’s Holy Trinity of Distillation, here’s the gist: a high-quality spirit matches the taste profile of the category it belongs to, while maximizing associated flavor and minimizing toxicity.

Example 1

An example? A whisky is a three-dimensional drink. It needs to hit the front, center, and back of mouth and tongue and throat and the flavor needs to last well over 20 seconds. A whisky where the front has gone (usually through oxidation while in the barrel) has lost a dimension and is no longer a three-dimensional drink, so not a high-quality spirit anymore. And if we compare two whiskies that are both three-dimensional, the one with more flavor offers the better and longer experience, as long as we off-set it with toxicity. If the flavors are “off” or bad, they don’t count. At least not in a positive manner.

A three-dimensional whisky is made according to its category, where a two-dimensional one isn’t. A whisky with a higher ester (taste molecule) count is a better whisky than one with a lower ester count, as long as we deduct for potential impurities and toxins. Impurities and toxins can add flavor, but these are both bad and unhealthy, and not markers of a high-quality spirit.

Example 2

Another example to help clarify quality. Let’s compare two gins. Gins are two- to two-and-a-half-dimensional drinks. The ones with a front and a middle are great for G&T’s. The tonic will provide the back-end flavor. The gins that also have a bit of back-end from themselves, a taste count of 10 to maybe 12 seconds, are great sippers. To be enjoyed by themselves. Or to be mixed with more carefully selected small-batch tonics that “sit” where the gin still leaves a flavor gap.

A two-dimensional gin that has only a middle and an end is not a good gin. In fact, it is normally hardly identifiable as a gin. It is not a high-quality spirit. A gin with a front and middle is good, where a gin with a front, a middle, and a bit of back-end is high-quality indeed.

But there is more. How about flavor intensity? How many esters are there, when we compare two gins that both follow the category’s flavor profile. And how many impurities do we detect? The gin with more esters and a lower level of toxicity is better.

How is quality made?

If quality can be defined, how can it be achieved? Via the right mashing, fermentation, distillation, and aging techniques, mostly. And by using quality ingredients and tools, of course. Manipulating the right ingredients in the right way with the right tools results in high-quality spirits. Want to learn more? Reach out to Veronika@iStillmail.com and register for the iStill University, please. We teach 200 students per year how to make better spirits. And y’all should know by now: craft distilling is all about making better, tastier spirits.

How does the iStill Laboratory help?

How do you know if you have created a high-quality spirit? To measure it is to know it! And that’s where the iStill Laboratory comes in. The iStill Laboratory scientifically analyses your spirit, gives objective feedback on the results, and even provides advise on how to improve.

The iStill Laboratory offers two levels of support to help you improve (or at least monitor) your spirit quality:

  1. SET Analysis (Smearing, Esterification & Toxicity Analysis);
  2. SOP Advise (Standard Operating Procedure).

Smearing, Esterification & Impurity Analysis

Your spirit is judged on the amount of heads and tails smearing that made it into the hearts cut of your spirit. The outcomes are compared to the specific product category and compared to category benchmarks.

Your sample will also be tested for total and specific ester count. Specific ester count relates particular esters to the front, middle, and back-end flavor sensations. Both total and specific ester count are compared to industry standard products from Big Alcohol. An analysis is made, where you get feedback on how your spirit scores relative to the category definition and Big Alcohol benchmarks.

The iStill Laboratory also establishes the amount of impurities. What’s the total level of impurities and what are the specific scores for the most important ones? Think sulfuric compounds, methanol, carcinogens, and copper particle contamination. Again, your spirit will be rated against Big Alcohol benchmarks.

Standard Operating Procedure Advise

If your spirit follows the category’s flavor profile and you outperform the Big Alcohol benchmarks, all is fine. You can use the Smearing, Esterification & Impurity Analysis to show your distributors and/or customers that you make better quality spirits, that are worth paying for. But if you feel you lag behind or didn’t completely hit all the boxes, well, you might want to dive in deeper. That’s where SOP Advise comes in.

SOP Advise goes a step deeper. The iStill Laboratory asks you for your current standard operating procedure (SOP) and confronts it with the findings from the SET Analysis. Based on the available chemical and practical distillation knowledge, an advisory report will be drawn up that helps you change your SOP to the effect that it will improve your spirits.


The SET Analysis can currently be ordered for EUR 1.495,-. The SOP Advise also costs EUR 1.495,-. These are introduction prices for the first ten customers. After that, prices will rise to a commercial level still to be established.


If you want to order the iStill Laboratory’s analysis or advise, please reach out to Robert@iStillmail.com. He will send you an invoice so that you can pay. After payment is made, ship us two bottles of the spirit you want the iStill Laboratory to test. The tests have a throughput time of 1 month. Outcomes and SOP’s are considered confidential. You can use the outcomes as you like, but we can not. Not unless we have your explicit consent.


How to use the services the iStill Laboratory offers? Here you go:

  • Test your spirit against Big Alcohol benchmarks;
  • Test your spirit against a specific competitor;
  • Spirit improvement;
  • SOP improvement;
  • Substrate assessment (how does a new ingredient affect taste);
  • Chemical spirit signature (does my spirit still have the same flavors as before);
  • GNS-testing (how pure is my GNS and which one should I buy).

Our chemist Willem performing inductively coupled plasma atomic emission spectroscopy …


Questions & Answers (3)!


We had a successful Drinktec 2022 in Munich. Hundreds of brewers and distillers visited our booth, asked questions, and expressed their interest in our disruptive technology. But what did they ask? What were the questions on their mind, as they saw the iStills? In a series of posts called “Questions & Answers” we will summarize the questions that were asked most as well as our answers.

Question 3

Where’s the copper?


iStills are primarily made out of stainless steel. Stainless steel is a high-grade, modern, non-reactive material. It lasts a very long time, because it is resistant and strong, offering the craft distiller a machine that lasts a lifetime.

Copper is a reactive material that rusts. It has limited longevity in a still. Copper particles, blowing over during distillation are toxic. So there are many reasons, when designing a still, to want to limit the amount of copper.

Copper is abundantly available with many other still manufacturers. The reason? Tradition, business model, and chemistry. Firstly, traditional still builders are basically copper smiths. They know how to process copper, more than they understand still design. That’s not merely an opinion. It’s backed up by the fact that not one copper still manufacturer has designed any new innovation in over a century and a half. Copper smiths, not still designers, there you have it.

Secondly, traditional still manufacturers are incentivized to continue building copper stills. As copper rusts and degrades quickly, it offers them the opportunity to sell more and more replacement parts. Parts on which they make money. Parts for which you do not have any other choice but to shop with them with.

Finally, sulfuric compounds, that may have formed during poorly managed fermentations, are catalyzed by copper. Copper is a medicine for a bad ferment. A medicine with very harmful side effects.

Here at iStill we train people how to correctly manage their fermentations, so that no sulfuric compounds are formed. Also, at iStill we design fermenters that give you total control over the alcohols and flavors you are creating. And if that isn’t enough, we can add a copper waffle to the bottom of your iStill column. It has the same surface area as a complete copper still, without the costs, the extensive cleaning protocols, and the copper particle contamination risk.


What reactions did we get, when answering the question of why copper plays such a minor role in our designs? The reactions ranged from “that makes total sense” till people being flabbergasted by the simplicity of how we solve their real world problems.

At your service!

The iStill Team

Copper serves the manufacturer more than it does the craft distiller …


Jamie Explains Why the iStill University Matters!

Hi Veronika,

Well, I finally made it back to Australia after a fantastic overseas trip, which obviously included the iStill University course. 

I want to thank you all, all of the team that took part in the teaching, the admin, and even the cooking!! I honestly felt that each iStill employee I came across went above and beyond to deliver with no short-cuts – to me there seemed a bar in standards that was set very high and you all as a team totally went over it. Even your help with the train strike and helping me get a flight to Italy, just great. A special shout out to Willem who really made sure i wasn’t just nodding my head but really had the grasp of what was being taught.

My limited skills as a distiller, starting on my own Journey, have been given a huge injection of confidence and I am really looking forward to rolling my sleeves up and getting stuck in, your course really had that effect on me and I look forward to growing my business with iStill in the future.

So also now I’m back you can send over the iStill mini package whenever it works for you and thanks for keeping it for me, I finally got permission to own a still 🙂

Warmest regards,


Do you want to become a craft distiller? Please reach out to Veronika@iStillmail.com and register your place at the iStill University! It’s the industry’s best educational program, rated at 9.8 out of 10 by the students …