Optimizing Yeast Nutrition!


Yeast converts fermentable sugars into alcohol. Sugar levels, temperature, oxygen levels, pH, and nutrients in the yeast’s environment all play an important role. Today, we investigate nutrition. Healthy yeast creates a higher yield and a faster ferment. So let’s dive in deeper and find out what nutrients it needs in order to perform!


Why does yeast need nutrition? Doesn’t it come fully functional? It does, but – just like you and me – yeast needs nutrients to keep going. And there is more. Yeast, in an oxygen-rich environment, so especially at the beginning of your fermentation cycle, multiplies. One yeast cell becomes two, then four, then eight, then sixteen, etc. Without additional nutrients, the available nutrition would have to be divided between more and more cells.


Yeast Assimilable Nitrogen (YAN) is very important. During the first 72 hours of your fermentation, the yeast will absorb it. During the fermentation, YAN is used to synthesize proteins, amino acids, other building blocks, that are essential to the yeast and its ability to produce alcohol.

A lack of YAN leads to an increased production of glycerol at the cost of alcohol production. YAN deficiency can decrease total alcohol yield by up to 10%. Put differently, by adding enough nitrogen, the craft distiller can potentially increase his yield with 10%!

But there is more. A lack of YAN also results in less esters and acids being formed. If you are educated in Odin’s Theory of Fermentation, you will immediately understand that this is bad for overall flavor development.

The optimal amount of nitrogen is 267 mg per liter. Amounts below 140 or above 400 mg per liter will result in non-optimal outcomes. The yeast may stall and stop producing alcohol all together.

To prevent such a situation from developing, add 0.6 grams of di-ammomium Phosphate (DAP) per liter.

Zinc sulphate

Zinc sulphate is another essential nutrient to yeast growth and performance. The yeast cells use it to grow. It is also a source of energy, via the production of NADH and NAD+. and it increases alcohol tolerance. Off the yeast, not of the consumer. 😉

Zinc improves the production of ethanol. Zinc ions help the yeast create vitamine B2, essential to yeast growth.

Zinc sulphate is absorbed during the first 48 to 96 hours of the fermentation. An ideal level is 0.4 mg per liter of fermentation. Values above 0.6 or below 0.1 mg per liter will result in the yeast stopping to function.

Add 0.0004 grams of zinc sulphate per liter.

Copper sulphate

Copper ions and zinc ions can react and form a superoxidedismutase. That word helps you win at Scrabble. It is also an enzyme that catches biradical oxygen atoms, that are toxic to the yeast, and turns them into O2, oxygen, which is exactly what it needs.

Copper ions help induce metallothioneïnesynthesis, which helps bind heavy metals, that would otherwise harm the yeast cell. It is also essential to the yeast’s metabolism and growth.

Add 0.001 grams of copper sulphate per liter.


Mash or otherwise mix substrate with water. Bring the mix to fermentation temperature. Add the above nutrients and mix them in. After that, add the yeast.

For more reading

Please see:

1.        Asif, H. K. et al. Comparative study of bioethanol production from sugarcane molasses by using Zymomonas mobilis and Saccharomyces cerevisiae. African J. Biotechnol. 14, 2455–2462 (2015).

2.        Arroyo-López, F. N., Orlić, S., Querol, A. & Barrio, E. Effects of temperature, pH and sugar concentration on the growth parameters of Saccharomyces cerevisiae, S. kudriavzevii and their interspecific hybrid. Int. J. Food Microbiol. 131, 120–127 (2009).

3.        Mendes-Ferreira, A., Barbosa, C., Lage, P. & Mendes-Faia, A. The impact of nitrogen on yeast fermentation and wine quality. Cienc. e Tec. Vitivinic. 26, 17–32 (2011).


5.        Albers, E., Larsson, C., Lidé N, G., Niklasson, C. & Gustafsson, L. Influence of the Nitrogen Source on Saccharomyces cerevisiae Anaerobic Growth and Product Formation. APPLIED AND ENVIRONMENTAL MICROBIOLOGY 62, (1996).

6.        Mendes-Ferreira, A., Mendes-Faia, A. & Leao, C. Growth and fermentation patterns of Saccharomyces cerevisiae under different ammonium concentrations and its implications in winemaking industry. J. Appl. Microbiol. 97, 540–545 (2004).

7.        Pretorius, I. S. & Henschke, P. A. Title: Influence of diammonium phosphate addition to fermentation on wine biologicals Mar Vilanova [1].

8.        Brice, C., Sanchez, I., Tesnière, C. & Blondin, B. Assessing the mechanisms responsible for differences between nitrogen requirements of saccharomyces cerevisiae wine yeasts in alcoholic fermentation. Appl. Environ. Microbiol. 80, 1330–9 (2014).


10.      Zhao, X.-Q. & Bai, F. Zinc and yeast stress tolerance: Micronutrient plays a big role. J. Biotechnol. 158, 176–183 (2012).

11.      Zhao, X. Q. et al. Impact of zinc supplementation on the improvement of ethanol tolerance and yield of self-flocculating yeast in continuous ethanol fermentation. J. Biotechnol. 139, 55–60 (2009).

12.      Raj, S. B., Ramaswamy, S. & Plapp, B. V. Yeast alcohol dehydrogenase structure and catalysis. Biochemistry 53, 5791–803 (2014).

13.      De Nicola, R., Hall, N., Melville, S. G. & Walker, G. M. Influence of Zinc on Distiller’s Yeast: Cellular Accumulation of Zinc and Impact on Spirit Congeners. J. Inst. Brew 115, (2009).

14.      De Nicola, R. & Walker, G. M. Zinc Interactions with Brewing Yeast: Impact on Fermentation Performance. J. Am. Soc. Brew. Chem. 69, 214–219 (2011).

15.      Šillerová, S. et al. Preparation of Zinc Enriched Yeast (Saccharomyces Cerevisiae) By Cultivation With Different Zinc Salts. J. Microbiol. Biotechnol. Food Sci. 2019, 689–695 (2019).

16.      Priest, F. G. & Stewart, G. G. Handbook of brewing. (CRC/Taylor & Francis, 2006).

17.      Vecseri-Hegyes, B., Fodor, P. & Hoschke, Á. The role of zinc in beer production. Acta Aliment. 35, 17–24 (2006).

18.      Walker, G. M., De Nicola, R., Anthony, S. & Learmonth, R. Yeast-metal interactions: impact on brewing and distilling fermentations.

Yeast Cell Division Caused Nutrient Deprivation …


We invented a way to purify your heads and tails!

Willem’s Miracle Powder

Making careful cuts for hearts, leaves you with heads and tails losses. Well, here is the good news: as of today they are losses no more! iStill’s chemist Willem has tested a powder and designed a purification protocol, that will help you clean up your heads and tails to the extend that they will become your purest vodka or GNS. Want to learn more? Yes, you do, so let’s dive in deeper!

The Goal

Heads and tails are full of flavors. Mostly off-flavors, and that’s why you cut them out. But a deeper analysis learns us that the vast majority of those heads and tails are actually … hearts. Good ethanol, contaminated by small fractions of actual lower and higher boiling point alcohols and their associated flavor molecules aka esters.

The goal of Willem’s Miracle Powder? To recover this ethanol, but to get rid of the bad alcohols and bad flavors. Now, redistilling heads and tails during a vodka program on the iStill does a great job at getting rid of the bad alcohols. But the compaction of heads and tails, leads to the associated bad flavors to leach into the ethanol recovery.

Again, the goal of Willem’s Miracle Powder and this new procedure? To destroy the esters found in your heads and tails factions.

The Thought Process

If you have followed the iStill University, you have learned all about esterification and how flavor molecules are formed. You remember Odin’s Esterification Formula? And how a low pH results in more flavor molecules or esters being created?

Guess what, the opposite is true as well! If you make your heads and tails factions very alkaline, instead of acidic, you can destroy the alcohol-carbon bonds that make up the ester molecule. Treating your heads and tails factions and then distilling it in vodka mode, breaks up the esters, recovers the ethanol, and helps you turn what was a loss into the purest vodka or GNS possible.

The Procedure

  1. Add your heads and tails faction to the iStill;
  2. Dilute the heads and tails faction to 30% ABV;
  3. Add sodium hydroxide (0.4 grams per liter of diluted heads and tails faction);
  4. “Sodium hydroxide” as in caustic soda, also used by breweries to clean their stainless steel brewing equipment;
  5. Mix the sodium hydroxide in (be careful, this is not the stuff you want to inhale or get in touch with!);
  6. Start the vodka program;
  7. Choose the heads stabilization program to be at least 60 minutes;
  8. Distill as per usual;
  9. Toss heads and tails, keep hearts – the most neutral and delicious vodka;
  10. Treat the boiler content with citric acid to bring pH back to 7;
  11. Drain your boiler and rinse the system with water.

The Results

The results of the above procedure are amazing. The worst heads and tails turn into a beautiful vodka or GNS. That’s not just our opinion, but a scientific fact. Do you want to see some of the proof?

A chromatographic overlay of a 1% ethyl acetate solution (a heads faction) in purple, a 0.1% ethyl acetate solution in yellow, an untreated heads sample in green, and the black line (look careful!), that signifies the heads sample after treatment with Willem’s Miracle Powder (aka sodium hydroxide):

The above chromatographic analysis proves that iStill’s Heads & Tails Purification Procedure successfully removes the associated headsy esters from a heads (the graph title mistakenly says “hearts”) sample.

But that is not all! How does the procedure do against other heads and tails flavors? Well, here is the outcome of further CG analysis. In purple you see the various esters available in an untreated heads and tails sample. The black, line that is significantly lower, represents the ester count after the purification procedure:

But that is not all! This procedure, since you basically use a cleaning agent, also makes your boiler shine as if it were new.

The Conclusion

iStill’s Heads & Tails Purification Protocol works a charm. It allows the craft distiller that possesses iStill equipment to process former heads and tails losses and turn them into the purest vodka or (reusable) GNS.

Still Design: Why Air Resistance Matters!


Air resistance is important when designing a car or parachute, but for a still? Really!?! Yes, it is. Distilling is all about managing and manipulating the vapors that rise from the boiler. The amount of resistance, that the rising vapors encounter, influences the speed of those vapors. And vapor speeds define flavor composition.

Okay, maybe we should call it vapor resistance, rather than air resistance, but it got your attention, right? And it is basically the same thing. Interested to learn more? You better be. Managing vapors successfully is what is required to become recognized as a skilled distiller, so let’s dive in deeper.

Cuts for flavors

Have you ever noticed how a fast stripping run isn’t ideal for making cuts? How, for your cuts to work out, a lower power setting usually works better? Cutting is about the master distiller deciding what flavors should be in the spirit and what flavors should be cut out.

Heads, hearts, and tails

As we saw in an earlier iStill Blog post, flavors associate with heads, hearts, and tails (for more reading, please see: https://istillblog.com/2021/06/10/whos-afraid-of-heads-hearts-and-tails/). Fruity flavors come over during the beginning of the run, followed by the hearts-associated substrate flavors. At the end of the run the earthy and rooty tails-associated flavors come over.

Since, during the distillation run, the original alcohol charge in the boiler is slowly depleted, the rising vapors will become less alcohol rich and more water dense. As a result the temperature of the gasses increases (water boils at higher temperatures than alcohol). The iStill takes advantage of this by having an extensive control and management system in place, that allows the distiller to cut consistently each and every time, given a certain power setting. It is the “given a certain power setting” part that I now want to draw your attention to.

Vapor speeds, separation, and smearing

Our stills are insulated. Therefore an increase in power results in the creation of more gasses and more product per minute or hour. Since the column and boiler are structural parts that do not all of a sudden change shape or size, that column – with a power increase – needs to process more gasses. A higher power setting will result in higher vapor speeds in the column.

Low boiling point alcohols (and their associated fruity flavors) come over during the early part of the run. They need relatively low energy settings to boil off. High boiling point alcohols (and their associated rooty, nutty, and earthy flavors) come over later in the run. These molecules need relatively high energy settings and higher vapor speeds to come over.

With the above in mind, now imagine that we do a slow run. The headsy factions boil off first, since they need the lowest amount of energy and the lowest vapor speeds to come over. When almost all the heads is gone, the transition towards hearts collection takes place. And when almost all the ethanol (and its associated substrate flavors) is gone, the tails slowly and gradually blend in.

Now imagine a fast run instead. A high power setting results in higher vapor speeds. The higher vapor speeds push hearts and tails into the first faction of the run. As a result heads aren’t separated and depleted. During a very fast run, like a stripping run, the whole batch is smeared and tainted with heads, hearts, and tails. No separation, so not a great flavor. Quick and dirty. Do you see how vapor speed is essential to the amount of heads and tails we smear into hearts, and therefore how essential vapor speed is to flavor composition? If you do, let’s continue with the next chapter!

Vapor resistance hampers run consistency

Consistent vapor speeds are essential for consistent flavor harvesting, which is essential for consistent spirit production. You want your whiskey, rum, or gin to taste the same, each and every production run, right? Resistance in the vapor path not only leads to inefficiencies, it also results in vapor speed fluctuation. And if you have read the above paragraphs carefully, you now understand that vapor speed fluctuation is basically the same as flavor fluctuation. Flavor fluctuation prevents the craft distiller to produce high quality spirits consistently. Hence our efforts to design stills with the lowest possible internal vapor resistance. The less vapor speeds fluctuate, the less flavor fluctuation you’ll experience in the drinks you produce!

This is why air resistance matters. Resistance creates vapor speed fluctuation. Vapor speed fluctuation creates flavor inconsistency. Flavor inconsistency equals poor (or at least: suboptimal) quality. Poor quality impacts the craft distilling industry at large, and your personal business specifically. Poor quality destroys reputations as well as bottom-lines.

Do you want to become a better craft distiller? Do you want a better reputation and a better bottom-line? Control your vapor speeds. And ask your equipment supplier what he has done, design-wise, to give you that control. “What did you do to prevent vapor resistance?”, “How does the technology you provide limit vapor resistance as much as possible?” are legitimate questions any still manufacturer should be able to answer. Only they don’t and they can’t. We do, and here are some examples of how iStill gives you total control over vapor speeds and associated flavors via vapor resistance reduction.

Wide boiler design

Given a certain boiler charge volume, a still designer can decide to make a tall and narrow or a lower and wider design. A tall and narrow boiler dissipates its energy over a limited surface area. As a result the boil-up will be higher, creating turbulence in the vapor bath above the liquids. This inner-boiler turbulence results in the column or riser being fed with vapors at speeds that continuously change. The constantly changing vapor speeds in the column result in more smearing of heads and tails into hearts, and in less control over the exact amount of smearing.

A wider and lower boiler gives a much larger surface area (square root function!) for vapors to boil off from. As a result, there is less boil-up, and less turbulence. The column can now draw the vapors from a more stable gas bed, at steady speeds. Steady speeds result in less smearing and more control over the amount of smearing! iStill has a wider and lower boiler design, specifically for that reason.


An uninsulated column creates a temperature difference between the outside and inside of that column. The colder environment cools the column. The cooler column liquifies rising gasses into (passive) reflux. This is more than just an inefficiency, because it also creates inconsistency.

An uninsulated column or riser results in passive reflux. Gasses that normally should have come over as product now fall back into the boiler. The colder the climate (or distilling hall) is, the more inefficiencies are introduced.

But an uninsulated column or riser is also a variable that boosts inconsistency. Cooler columns lead to more passive reflux and lower overall vapor speeds. Lower vapor speeds may make it difficult to create the right amount of smearing, for a certain product category. When the climate or temperature in the distilling hall changes, a bigger or smaller temperature differential establishes, resulting in lower or higher vapor speeds, and less control over flavor harvesting and reproducibility.

iStill insulates its columns to minimize the temperature difference outside and inside the column. A low to non-existent temperature difference leads to a more efficient run (less passive reflux), stable vapor speeds, and reproducible and consistent outcomes.

Inner column design

Let’s compare iStill’s perforated plate still with a traditional bubble-cap fruit brandy still. The traditional bubble-cap column has plates that hamper vapors, where our design allows vapors to pass through. Fruit brandy stills have sight glasses that stick out, generating vapor resistance in the column.

Traditional stills have dephlagmators that cool part of the gasses back to liquid state, depending on cooling management, coolant pressure, and coolant temperature, air pressure, and the differential between inner and outer column temperature. Their dephlags are designed with a limited number of through-tubes.

iStill designs its coolers with a maximized number of through-tubes. More surface area creates less turbulence. Less turbulence results in steady vapor speeds and consistent flavor profiles.

iStill doesn’t use dephlagmators and cooling management, but instead invented the column cooler and liquid management. These innovations have taken variables that influence resistance and vapor speeds out of the equation. Coolant pressure, temperature, air pressure, and the difference between inner and outer column temperatures no longer screw things up.

If you didn’t yet know why you wanted an iStill, now you do.

Studying the peloton-effect helps us design better stills …


Bubble-Cap Stills Suck at Making Whisky!


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. 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? 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 …

Who’s Afraid of Heads, Hearts, and Tails?


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.


iStill University Certified Master Distillers Training!


After over a year of not being able to give on-site trainings at iStill HQ, we are proud and happy to announce we are opening up again! The iStill Distilling University organizes the Certified Master Distillers Training at iStill HQ.


The iStill University Certified Master Distillers Training takes place from October 4th till October 8th, in Woerden, at iStill HQ, located under Amsterdam, at around 30 minutes from Amsterdam Schiphol Airport.


The Certified Master Distillers Training is a practical training, where we train you how to make brandy, gin, rum, vodka, and whisky, as well as liqueurs. The focus is on “learning by doing”. You’ll spend as much time as possible behind the iStill Mini to make a variety of spirits, and to learn how to manage your still as well as how to make perfect cuts. Mashing and fermenting, and runs on the bigger iStills will also be part of the curriculum.


The Certified Master Distillers Training picks up where the iStill Certified Craft Distilling courses stop. The Craft Distillers course teaches you the theories around distilling, where the Master Distillers course focusses on hands-on training. The Certified Craft Distillers course is theoretical, the Certified Master Distillers Training is practical.

In order to participate at the Certified Master Distillers Training, you need to be a Certified Craft Distiller already. We need everybody to be on the same page, on the same theoretical knowledge-base, before we can dive in deeper via the Certified Master Distillers Course.



·      Welcome

·      Theory of distillation recap

·      Smelling all alcohols

·      Filling the iStill Mini with wine

·      Fractioning the wine

·      Making cuts to turn wine into brandy

·      Watching brandy program on iStill 500


·      Theory of fermentation recap

·      Mashing 10 liters

·      Fermenting 10 liters

·      Organoleptic training overview

·      Visiting the windmill

·      Dinner


·      Feedback from day 1

·      Theory of extraction recap

·      Extraction on the Mini

·      Extraction on the i500

·      Creating hard seltzers

·      Sensory training: fruits and grapes


·      Creating a program on the iStill

·      Programming the iStill

·      Cleaning the iStill Mini

·      Distilling vodka on the Mini

·      Distilling vodka using ABV-C


·      Feedback from day 2

·      Turning extracts into liqueurs

·      Turning extracts into essences

·      Finishing run: vapour speeds


·      Sensory training: botanicals

·      DIstilling gin on the iStill Mini

·      Sensory training: faults

·      Visiting Rummiclub Distillery


·      Feedback from day 3

·      Sensory training: wood

·      Cleaning the iStill Mini

·      Distilling rum frow low wines

·      Aging spirit with heat and oxygen

·      Aging spirit with ultrasound

·      Using wood chips for aging


·      Distilling fermentation on the iStill Mini

·      Sensory training: aged spirits

·      Measuring and diluting your spirit

·      Evaluation of the spirits

·      Food pairing theory

·      Graduation dinner


Participating at the Certified Master Distillers Training costs EUR 2.495,-. Two dinners and four lunches are included, as well as your certification.


Do you want to participate? Please know we maximize the number of students to 12. You will be working with the iStills Mini in groups of 2.

For registration, please email Veronika@iStillmail.com

Pre-Covid picture of the iStill Distilling University …


Three 2020-model iStills 100 for Sale!

Due to Covid, a customer that ordered three iStills 100 Hybrid Manual in early 2020 now cannot take delivery of them. The units never left iStill HQ and are brand new. They now become available for sale. If you want to order one (or more), please reach out to Esther@iStillmail.com. Here is the specification list:

  • 100 liter insulated boiler (net);
  • 2 1/2 inch diameter insulated hybrid column with reflux valve;
  • Column packing;
  • StillControll Probe & App;
  • 3.5 kWh heater, 230v;
  • Can pot distill and column distill (up to 96%);
  • iStill Distilling University (online course) at EUR 1.895,- is included for free.

Price per unit? EUR 9.950,- ex VAT and ex crating and transport. We can ship the unit all over the globe, or you can come by and collect it at iHQ. Coffee is always ready, and we usually have a drink to share as well! Here are some pictures of the units:


Never Mash Again! (2)

Here’s an update on the first round of tests we did. The good news? We have proof of concept! We succeeded in:

  1. Converting starch to fermentable sugars;
  2. Converting starch to fermentable sugars while fermenting.

The bad news? We have like a dozen more test trials to do in order to fine-tune procedures and come up with the best and most efficient protocols.

Then again … we’ll keep you posted!

Simultaneous mashing and fermenting …


Whiskey – What Equipment Do I Need?


Planning a distillery can be daunting. What equipment do I need? A simple question, but there are so many answers that are rooted in even more considerations. This post is the fifth of a series called “What Equipment Do I Need?”. Each post highlights one consideration. This week? Whiskey! What equipment do I need to make whiskey?

Whiskey making process

There are basically three fundamental steps to whiskey making:

  1. Mashing;
  2. Fermenting;
  3. Distilling.


Mashing is the process where grain starch is converted into fermentable sugars. It is done by putting the cracked grains with warm water and certain amounts of enzymes in a vessel. Mixing the concoction and carefully managing the temperature are critical. Since mashing takes 4 to 6 hours, you need but one masher.


Fermenting is the process where grain sugars are converted into alcohol and flavor molecules. It is done by adding yeast to the mash, and by carefully managing temperature and pH. The process takes about 4 to 5 days, so traditionally you need 5 or 6 fermenters.


Distillation concentrates and selects the alcohol and flavors. Usually a double distillation cycle is needed. Since distilling takes about an 8 hour shift, traditionally two stills are needed. One for the first stripping run, another one for the second finishing run

iStill solutions

The iStills can basically mash, ferment, and distill. So one iStill (preferably as big as you can afford and house) is all you need. Let that sink in for a moment. And if you still want to go the traditional route of a separate masher, 6 fermenters, and two stills, well, we have these too!

Okay then, 6 steps …