Aspects of Distillation (1): Air Pressure!


“Aspects of Distillation” is a new series the iStill Blog will host. It aims to cover as many aspects as possible. Aspects of – you guessed it! – the distillation process. Think alcohol formation, flavors, mashing, distillery design … and more. In fact, if you have a suggestion, please email us the aspect you want us to dive into. Via Today’s topic? The influence and importance air pressure has on distillation.

Air pressure

There are three things I want you to consider, when investigating air pressure and its role in the distillation process:

  1. Air pressure directly influences the flavor composition of the drinks you produce;
  2. Air pressure constantly changes;
  3. So changing air pressure constantly changes the flavor composition of your drinks.

Starting this investigation with air pressure variability, I want you to understand that higher altitude results in lower air pressure. Also – at any altitude – air pressure changes constantly.

When you make drinks like gin, whiskey, rum or brandy, you cut for heads, hearts, and tails. The best way to measure and replicate cuts is by looking at the temperatures in the column or riser of your still. Do you cut from heads to hearts at 82c? Good, you now have a reference point to do the exact same run again tomorrow, and create the exact same cuts again, by using 82c as the switch-point from heads to hearts, right? Wrong.

As air pressure constantly changes, so do associated boiling points. In other words: given yesterday’s air pressure, the 82c cut-point may have been spot-on. But what if air pressure is lower, due to a bad weather front moving in? What was a good decision at 82c yesterday, may need to be 81.6c today.

Now, 0.4c degrees difference does not sound like a lot, but look at it this way: if it takes your still 25 minutes to move up in temperature 0.4c … that now means you either have collected 25 minutes of heads into your hearts, or that you just lost 25 minutes of good product to a badly judged heads cut!

Cut management via a parrot and ABV only deepens the problem. Cut management by taste is very subjective and influenced by what you ate, so no solution either. So how can this problem, that hugely influences flavors and therefor the consistency of craft distilled spirits, be solved?


iStill designed an air pressure sensor. It measures the air pressure every second. If the air pressure changes, the sensor informs the computer. The computer then automatically adapts your cut-points to compensate.

If we use the above example, with yesterday’s heads to hearts cut taking place at 82c. Today, you want to replicate the same recipe, so you look it up in your product library, load it into the iStill computer, and tell the iStill to start executing. The air pressure sensor notices immediately (and constantly) that the air pressure – relative to yesterday – is 0.4c off. As a result, the computer automatically changes your heads to hearts cut from 82c to 81.6c. If the air pressure monitor sees a change from 0.4c to – say – 0.3c, the heads to hearts cut will immediately compensate to 81.7c instead of 81.6c.


All iStills are equipped with air pressure sensors and the resulting dynamic cuts management for heads, hearts, and tails. It is a standard feature to our stills. It helps craft distillers make better product, more consistently, and with less guessing, effort and supervision.

iStill’s amazing air pressure sensor …


Distilling Whiskey and Rum Sustainably!

Management summary

The direct operating costs of producing a liter of new make whiskey or rum on an iStill, ready to barrel at 65%, are EUR 0,49 versus EUR 1,99 on a traditional copper potstill. Producing whiskey or rum on an iStill reduces operating costs with as much as 75%, when compared to a traditional copper potstill. The lower operating costs of running an iStill translate into higher margins and a more sustainable, future-proof business model.


This iStill Blog post presents an operating cost comparison for new make whiskey or rum production. iStills versus traditional set-ups. Why operating costs are important? Well, the lower they are, the higher your profit margin – given a certain selling price. Higher margins allow you to make more money or use part of that extra margin to weather through tough times. Also, lower operating costs signal a more eco-friendly, more environmental and sustainable business model. Less energy consumption equals a lower carbon footprint.

Of course we know the iStill numbers through-and through. The numbers of traditional stills, that we present in this iStill Blog, are based on feedback we got from customers experienced in running traditional equipment before switching to iStills. If the manufacturers of more traditional, copper stills feel that the examples underneath do not do their distilling solutions total justice, please reach out to us directly, so we can discuss and – where needed – amend.

Operating costs

Operating costs are the expenses associated with the maintenance and administration of a business on a day-to-day basis. Rent of the building, power to run the stills, the costs of buying in grains or other substrates, staffing costs, equipment depreciation costs, etc.

In order to keep this post relatively simple and to the point, we’ll focus on the variable costs of running the still, depreciation costs of your distilling machine, and the staffing needed to keep on distilling. Costs like the rent of the building or substrate purchase costs won’t be investigated, since they are (in the context of this iStill Blog post) considered a given. Meaning they don’t necessarily vary a lot between different still options.

Calculating energy costs for whiskey or rum

The efficiency number of a traditional potstill is around 35%. A traditional potstill needs two distillation cycles to bring an 8% whiskey beer or rum wine to the barrel aging strength of 60 – 65%. The iStill can turn an 8% base beer or wine into 60 – 65% new make in one go. So you save the manpower and energy of at least one run.

The iStill 2000 uses around 280 kWh to make rum or whiskey new make spirit. The associated costs are per run are well under EUR 50,-. Given the inefficiencies of the traditional set-up, a total energy usage of 800 to 1000 kWh is expected per run. This translates into direct energy usage costs, for a double distillation, of around EUR 190,-.

The amount of 2000 liters of base beer translates into about 220 liters of 65% strong new make spirit. When we divide the energy usage per still type by the number of liters of new make produced, we can learn the energy costs per liter. For the iStill the energy costs per liter are EUR 0,22. For the traditional copper potstill the energy costs per liter are EUR 0,87.

Calculating depreciation costs for whiskey or rum stills

A traditional 2000 liter copper still, made by a reputable manufacturer costs at least EUR 200.000,-. The iStill 2000, with some options, is around EUR 80.000,-. Because the iStills are made from chemically resistant stainless steel, instead of copper, the unit has an expected longevity of around 20 years.

The copper or stainless steel boiler of a traditional set-up may have the same longevity or slightly less. The copper column or riser oxidizes and suffers from the continuous need for (acid) cleaning. It is usually eaten away in around 10 to 15 years. Adding up boiler and column life expectancy for traditional potstills and averaging them out, leads to an overall total system longevity of 15 years for a traditional copper potstill.

Following a lineair depreciation curve, the 80k iStill 2000 has an annual depreciation of EUR 4.000,-. Based on 200 runs per year, the depreciation costs per run are EUR 20,-. When one run produces 220 liters, the depreciation costs per liter are EUR 0,09.

Following the same lineair depreciation curve, the EUR 200.000,- traditional copper potstill has an annual depreciation of EUR 13.300,-. At 200 runs per year, this translates into EUR 66,50 of depreciation per run or EUR 0,30 per liter of new make spirit produced.

Calculating staffing costs for whiskey or rum

Manning the still costs time, and time is money. Managing a traditional still asks for constant supervision. Cleaning can take 2 to 3 hours. Often the boiler design and column/riser design are not optimized for 8 hour shifts. How much manpower does it take to run a traditional still? At least 1 FTE. How much manpower does it take to run the iStill, which is automated and needs much less cleaning down-time? Around 0.2 FTE.

Say that hiring a distiller costs EUR 36.000,- per year. Running a traditional set-up then adds EUR 36.000,- to your overall costs. The iStill – by comparison – costs less than EUR 8.000,- to staff. A stunning difference of EUR 28.000,- per year.

In the above example, where we use a 2000 liter still to make 220 liters of 60-65% new make spirit per run, doing 200 runs per year translates into 44.000 liters of new make. The staffing costs of a traditional system are EUR 36.000,-, which translates into additional variable costs per liter of EUR 0,82. The much lower effort needed to run the iStill 2000 translates into only EUR 0,18 of staffing costs per liter.

iStill: reduce your operating costs by 75% …










iStill Distilleries Help Battle Corona!


As the world hordes toilet paper and hand sanitizer, more and more iStill distilleries switch from spirits to hand sanitizer and detergent production. I guess making toilet paper with an iStill is a challenge, where producing hand sanitizer isn’t?


We sorta lost count of who is helping out to relieve shortages, help care institutions, hospitals, or simply the citizens of their city, but here are a few:

  • Ireland: Listoke Distillery (in production);
  • Northern Ireland: Boatyard Distillery (in production);
  • Scotland: Verdant Distillery (in production);
  • England: Exmoor Distillery (soon);
  • Belgium: Sterk Stokers (in production), Acker & Go (soon);
  • Cyprus: Crimdell Distillery (soon);
  • USA: Jersey City Distillery among many others, Kyle Wray, Jeff Denise, Joe Canella, Michael Hart, and Ron Folino, Frank Kudlack and Lisa Desrocher;
  • Australia: Brisbane Distillery, Earp Distillery (both in production);
  • Virgin Islands: Mutiny Rum (in production);
  • Netherlands: iStill HQ/”In Onschuld Initiative” (in production), The Stillery (soon).

And that’s just a few of ‘m!


If you want to make a hand sanitizer, please use the WHO recipe. You (as a distiller) can either use remaining feints (heads & tails) or GNS or even new make rum or whiskey as a starting point. Like this:

  1. Bring the base alcohol to 70% (via distillation or dilution);
  2. Add around 1% of glycerine;
  3. Mix well;
  4. Bottle and distribute.

iStill is already producing 1,000 liters of hand sanitizer per day …


Notification to the Craft Distilling Industry!


There is something we discovered and that we need to talk about. Over the last year, we have investigated the manufacture of copper stills next to our existing stainless steel iStill suite. Why? Simply because, when we look at the market, the majority of stills being sold is still made from copper.

I want to inform you that, based on recent research findings, we will not build copper stills. Is that what I feel we need to talk about on an industry level? No, I do not propose to discuss our decision. What I want instead, is to discuss why we decided to stop the copper project. The reason behind our decision affects us all and is therefor a topic that deserves a wider discussion.

Here is why we stopped developing copper stills: ethyl carbamate formation.

Ethyl carbamate formation

Ethyl carbamate is carcinogenic. It can cause cancer. Ethyl carbamate is formed during distillation, when the run is performed with a copper column or copper riser.

Fruits (like apples and apricots) and grains (like barley) contain cyanide. During fermentation the cyanide is released into the wash. During distillation a part of it travels up the column or riser.

When that column or riser is made from copper, the cyanide oxidizes with copper into cyanate. And when cyanate comes in contact with alcohol (in your still or in your bottle), it forms the toxic ethyl carbamate. These are the schematics:

cyanide + copper => cyanate + ethanol => ethyl carbamate

Glass and stainless steel columns and risers are chemically resistant. Research shows that glass and stainless steel do not transform cyanide into cyanate into ethyl carbamate. Like this:

cyanide + stainless steel / glass ≠ cyanate + ethanol ≠ ethyl carbamate


Since we now know that copper stills cause ethyl carbamate formation, a carcinogenic substance, shouldn’t something be done about it? Isn’t it in the industry’s interest to manage this, preferably to zero, or as close to zero as possible? Can craft distillers afford not to act, given their responsibility towards their customers, the consumers? And do you feel we need to play a role here?




iStill Support for Breweries!


More and more breweries expand into distilling, and that makes total sense. As a brewer, you already make beer and work in the alcohol industry. What makes more sense than to double your product portfolio by turning part of your beer into beer brandy, whiskey, vodka, or gin? Since most brewers, however, are new to distilling, iStill wants to help them cross the gap. How? Let’s dive in deeper!

Brewstillery Calculator

The Brewstillery Calculator helps you with the number crunching. Just fill in how big your brew system is, then add the alcohol percentage of your beer, and you will immediately learn how many bottles of whiskey, beer brandy, vodka, or gin you could produce.

Free e-Book

Our CEO and world-renowned distillation guru Odin wrote a short e-Book that answers 21 questions related to distilling. Everything you always wanted to learn about distilling? And maybe a bit more …

Interview with existing brewstiller

Travis Peterson, owner of Meadowlark Brewery & Distillery, explains the “how”, “why”, and “what” of setting up a brewstillery. You’ll find the interview we did with him helpful, we are sure.


The iStill University’s 4-day course trains you to become a distiller. It is a hands-on training, where you learn how to make spirits and how to operate the distilling part of your business.

Landing page

Please find our dedicated brewstillery landing page. All the above support can be found there. The address is:

Picture of the brewstillery e-Book …







Odin explains poor still design (2)!


What we post here is an account of iStill’s CEO, Odin, helping out a distiller that has difficulty choosing the right still for his distillery. The distiller got a one-day training on a Holstein and now mistakes a short run-time for speedy and efficient production. There is also a mismatch between the product he wants to make (whiskey) and the product the Holstein is designed to make, which translates to underwhelming spirit quality.

There are two reasons to post this on the iStill Blog. First, it can help create awareness that there are many poorly designed stills out there. And if you end up buying one, you might find yourself in a bad situation, where you cannot produce the quality or product you aimed for. Let this iStill Blog post serve as a warning. Secondly, this post shows that still design is a science, based on facts, and not something artsy-fartsy, romantic, close to magical, based on opinions.

This post does not intend to harm another manufacturer of distilling equipment. Even though, after reading what we have to share, it may feel like it isn’t exactly a positive endorsement for them either. We considered what was more important: informing you, so you will be better prepared when it comes to still selection and purchase, or keeping our mouths shut and supporting the BS out there, even though it might hurt fellow craft distillers as yourselves. We decided to do the first. If for no other reason, simply because of all the positive feedback you gave us on the first post on poor still design from just two weeks ago. And it isn’t the first Holstein we encounter with a column too big for its boiler.

The distiller’s still design misconception

The distiller had a one-day training on a 600 liter Holstein with a huge column and overcapacity steam boiler. This allowed the training facility to do a run in around 2 1/2 hours, resulting in 3 runs during a (training) day. Given the advanced technology iStill has on offer, he reached out to us and asked us if the iStills also do 2 1/2 hour runs. At first, he didn’t understand why iStills have run times of around 8 hours, so Odin explained it to him.

Odin’s answer

“From a still designer’s perspective, a still that performs a run, from start to finish, in 2 1/2 to 3 hours, is a sub-optimal design. If the heat source and the column are so big, that they can process a boiler-fill in such a limited amount of time, to me that signals that the boiler is basically way too small. This may be beneficial for training, but not for actual distilling.

I design the iStills with a normal workday in mind. And a normal workday is 8 hours. Why I choose that approach? Well, imagine that every run starts with filling the boiler, then heat-up, then the actual run, then draining the boiler remains, and finally: cleaning. Filling, heat-up, draining, and cleaning are basically down-time. Since it is down-time, it is basically an inefficiency that you want to minimize. So, when designing a still, I want to limit the time spent with these downtime processes. And by far the best way to achieve that, is by designing boiler size, heat-source, and column in such a way that the total run time, of a single run, is close to 8 hours. The distiller now only has to fill, heat-up, discharge, and clean his still once. Filling and heating-up before the run. Discharging and cleaning, only once a day, at the end of the run.

A still with too small a boiler, that has a run time of 2 1/2 to three hours, needs multiple fill, heat-up, discharge and cleaning cycles. Multiple runs translate to a longer total down-time. And beware: you now also need to attach and clean the pump and hoses twice or three times during your 8 hour workday, so inefficiencies accumulate.”

Run-time misconception

The distiller intervened and said that he loved the speed of the 600 liter Holstein. “That way I can do 3 runs a day and process 1800 liters!” Upon understanding that the iStill 500 would run for around 8 hours, he said: “So that unit is very slow, then, isn’t it?”

Odin’s answer

“The iStill 500 is not slow; it is a machine that is optimized for an 8 hour workday, with the goal to limit down-time. If you want to process 1800 liters per day, like you could do in the small boiler designed Holstein, you need to compare it to the iStill 2000. A unit that can not just process 1800 liters, but 2000 liters in 8 hours – a first easy gain of 10% over running the Holstein three times a day.

Not only does the iStill 2000 give you 10% more capacity, it does so while being more affordable to purchase and less costly to run. The iStill 2000 costs EUR 70.000,- with all options included, the heating system being an integral part of the system. The Holstein costs EUR 200.000,- and that’s without investing in the heat source (a 50k steam boiler) and piping (another 50k). Purchase-wise the iStill 2000 costs only a fourth of the installation price of the Holstein. Given the 90% efficiency of the iStill, and comparing it to the 30 to 40% efficiency of a Holstein, expect your run costs per liter of spirits produced to double or triple, when opting for an uninsulated, copper, traditional, 1870’s still design from Germany.”

Spirit quality misconception

By now, the distiller thoroughly got wat Odin was explaining, and he moved on to the next topic: even though the distiller thoroughly loved the training experience on the Holstein, he felt the whiskey / New Make Spirit they made was not very impressive. He wanted to make sure that iStill could help him at making better spirits.

Odin’s answer

“The Holstein uses bubble capped plate technology. This is a Southern German (some say Elzas) innovation to help make better fruit brandy. Bubble caps create a structural (fixed) liquid bath on the redistillation plates, that work amazingly well as a tails trap. No tails come over, which tremendously helps fruit brandy production, because fruit brandy is a forward cut, headsy, fruity product that can easily be overwhelmed by non-intended tails smearing.

Whiskey is different, the opposite almost, because whiskey is a 3-dimensional product, heavily dependent on tails smearing, with a long resulting throaty, nutty, root-like, earthy finish. The reason why you were not impressed with the New Make Spirit produced on the Holstein, is because it basically is a machine intended to make fruit brandy, not whiskey. As a result the New Make Spirit you made and tasted lacked in back-end flavor. No worries with the iStill. We do not use bubble cap plates that prevent gentle early tails smearing. With an iStill you, not the (antiquated) technology, decide on the amount of heads and tails smearing, and the associated fruity and nutty, earthy flavors you get over in your drink.

Finally, there are two more things to consider. Remember the short vs. long run times? And the steam boiler that indirectly fires the Holstein? Indirect heating, like in the Holstein,  prevents the Maillard Reaction to take place. All iStills have direct, instead of indirect, heating, because the associated Maillard Reaction gives our customers up to 25% more flavor. And longer runs add to esterification (the longer runs help create more esters AKA flavor molecules). The short run-time of the sub-standard design you trained on prevented additional esterification to take place. There you have it: sub-standard design leads to the meager taste you experienced, via the prevention of tails smearing, a lack of Maillard Reaction, and low overall esterification.

A lengthy answer, but I hope you like the effort of me informing you about potential issues so you can better decide on the most adequate distilling solution for your future craft distillery.

Regards, Odin.”

The iStill 2000: optimized for an effective workday at the distillery …


Charles gives feedback!

“Finally back in South Africa. What a pleasure spending time with you all. Hope to stay in touch one way or another. Thank you for the inspiration – lots of possible products on the horizon. And a fantastic course, well presented by all at iStill. Without a doubt our next still. Best regards. Charles”

More on Charles and his Six Dogs Distillery? Please read this:

Beautiful South Africa …


Making Wheat Vodka (1)!

Here are pics of Mark Elia from Long Branch Distillery making wheat vodka together with iStill’s William Vermeulen. Mashing, as you know, is the first step. Mashing is where starches are converted to sugars using hot water as a medium. In this case, the masing (and fermenting and distilling) are done in the iStill 2000. Here are some pictures!

Bring water to strike temperature …


Add grains and enzymes …


Mixing …


Remote control …