Calvados: Aged Apple Brandy!

Calvados is aged apple brandy from the French Calvados region. Normandy, where Calvados is situated, grows traditionally many apples. Cider makers use the apples to make cider out of ‘m. Calvados distillers make a dry cider and distill that into a white apple brandy that’s then barreled. After two years it can be called “Calvados”.

Calvados, depending on region, can be single or double distilled. For the double distillation, often an “Alambic Charantais” is used. For single distillation any column will do. Distillation and maturation strength? Usually around 70%.

Apple is a fruit and it is generally considered a fruit with very limited flavor. The apple’s thin skins are the reason, since that’s where most of the flavor of any fruit can be found. How do Calvados distilleries work around that? Well, they have access to over 200 varieties of apples. Each with its own flavor profile. Not all of them are necessarily edible, but they do provide flavor. Sweet, tart, or bitter. A Calvados producer, using as many as 100 varieties of apples for his spirits, is no exception!

Depending on the region, fermentation times of up to 2 months can be used. The longer the fermentation, the higher the degree of esterification. More esters equals more flavor. A need trick to get around the relatively low flavor that apples in general provide!

The cuts management towards creating good Calvados is both heads-oriented and tails-oriented. The apple flavor can be found in the heads smearing. The tails smearing is needed for the white drink to stand up to the wood flavors provided by the barrel it ages in.

Fun facts on Calvados? Charlemagne already spoke of apples being grown and cider being made in the region. And records of spirits distillation go back to the mid 1500’s.

Calvados is both used as an aperitif and as a digestive. So before a meal and – say – after dinner. More interestingly, it is – in French culture at least – also used as an “in between serving”. The Calvados is used in between courses to reignite appetite.

Finally, the heads smearing that is essential for the apple flavor of Calvados, poses a challenge. Heads factions quickly oxidize and diminish, potentially limiting the barrel aging time to about two years. The solution? Calvados producers can add new make apple brandy spirit to replace the angels share. This way, more apple flavor is added over time. Also, a fuller barrel results in a lower exposure to oxygen, and therefore further lowers the rate at which heads oxidation takes place.

Do you want to learn about heads, hearts, and tails? And how fermentation protocols influence flavor composition and intensity? Do you want to learn how to distill any spirit, Calvados or otherwise? Then reach out to and register for the iStill University. The distilling industry’s best and biggest educational facility is at your service.

The Calvados region …

A Calvados for Odin …

If not our Technology, then at least our Design!

We are in Italy for the Distillo Expo. An initiative from our CEO Odin, executed to perfection by Claudio and Davide and their team! As we are meeting up with hundreds of existing and future Italian craft distillers, we had an hour (before opening) to check out if the “competition” had anything new to offer.

Outcome of our informal research? Nothing. Still the same old 1870’s technology. But wait, there is one exception. Or at least one change! One of the Italian offers decided to change their color scheme. From stainless steel to … stainless steel painted black. Not exactly iStill, but – at least visually – a step towards the future?

It does remind us of the “downfall” of the wooden shoe in Holland. Everybody walked on white wooden shoes And then leather shoes started to take over. The manufacturers of wooden shoes saw their days were numbered. What they did? They changed the design of the wooden shoe to resemble a leather shoe with straps. A sign on the wall? Check it out for yourselves!

Extending our Lead: Advanced Distilling Conquers the World!

Nine years ago I started iStill. The mission? To make distilling easy. To make craft distilling viable. To empower craft distillers around the world via hands-on and theoretical education. To bring technology to the market that slashed energy, labor, and investment costs, and is able to reliably create high-quality spirits in a reproducible manner.

Today celebrates a milestone. We have over 1,000 customers! Over 1,000 craft distillers, from all over the world, use our amazing technology to make a living, to produce better spirits more consistently, and to provide for their loved ones. Over 1,000 families, master distillers, businesses that connect, that share, that nib away at Big Alcohol’s market share, one glass at a time. Over 1,000 craft distillers that own the future of our industry …

On behalf of the iStill Team, I want to express our feelings of both gratitude and pride. Thank you for choosing iStill, thank you for making this happen.

At your service,

Drs. H.E.J. (Odin) van Eijk MScBA, etc.

Founder & CEO of iStill.

Today’s map of the world looks kinda iStilly …

Grapes too Bad for Wine are Perfect for Cognac!


France’s Cognac region is famous for its spirits. Cognac is considered the best fruit brandy in the world. It ages well in oak barrels. Often as long a whisky. It has a full-bodied flavor composition, which is amazing for a fruit-based spirit. And – here it comes! – Cognac is made from grapes that are considered too bad to make a drinkable wine from! Here’s an interesting fact that we need to dive deeper into. There’s much to learn, so let’s get started.

Location, location, location

The Cognac region sits north of the Bordeaux region. Bordeaux is world-famous for its wines. The Cognac isn’t, because the colder climate it faces, results in smaller grapes, with a lower sugar content, and generally a higher acidity level. Making wine in the Cognac would result in poor yield, low ABV, and a sour, very sour wine.

Every disadvantage has its advantage

In a weird twist of events, the disadvantageous climate and grapes for wine, turned out to be perfect for brandy making. So much so, that it’s the qualities of the grapes, and the resulting bad wine, are essential for the creation of the world’s best and most full-bodied fruit spirit! What those qualities of those Cognac grapes are?

  1. Low sugar content
  2. Thick skins
  3. Acidity

Low sugar content

As the Cognac region sees less sun hours than for example the Bordeaux, the grapes end up with a lower sugar content. Low sugar content results in the Cognac wine being low in alcohol. Where a Bordeaux wine easily hits 13%, Cognac wines seldomly exceed 9%.

Now, imagine taking the very best Bordeaux wine, at 13%, and via distillation, maturation, and dilution, making a bottle of brandy out of it at 40%. The alcohol percentage, and most of the flavor of the 13% Bordeaux wine, will be concentrated about three times. Three times 13 equals 40 … or thereabouts.

All right, let’s move on to that 9% Cognac wine. If you distill, age, and dilute it to a bottle of brandy at 40%, the alcohol and flavor concentration is well over 4x. A lower percentage wine results in more flavor concentration! And that’s one of the secrets of what makes a great Cognac: the disadvantage of a low alcohol yield results in 35% more flavor concentration, comparative to Bordeaux wine. That’s 1-0 to the Cognac grape, when making great brandy is the goal!

Thick skins

Overall, the grapes from the Cognac region have thicker skins to help protect them from the colder climate. Why thick skins are a bad thing in the wine industry? Because it means less fruit juice so less of the base material from which wine is made. Why thick skins are great for brandy making? Because over 80% of the flavor is concentrated in the skins of fruits. Thick skinned grapes result in bigger flavor brandies. 2-0 for the Cognac region when it comes to spirits? You bet!


Acidity creates an almost undrinkable wine, but acidity in fermentation creates … tails! Tailsy alcohols and tailsy flavors. Flavors of the third dimension. And that is an amazing achievement, since fruit brandies by definition have those fruity, first dimension flavors, but lack those all-important back of mouth, long-lasting, flavors that any spirit that desires barrel aging needs.

The acidity levels of Cognac grapes and wines add exactly those flavors that make the spirit three-dimensional. And at the same time, since flavors associated with tails smearing make up 50% of the total flavor count (or ester molecule count), this is exactly what’s needed to help the base Cognac brandy stand up to the wood flavors, that come from extended barrel aging.


Every disadvantage comes with its advantage. Bad wine translates into the best fruit brandy in the world. This post explains why. If you want to fully understand the how, then reach out to and register for the iStill University, the distillers world’s biggest and most advanced educational center.

Small, thick-skinned, and sour Cognac grapes …

Making Whiskey: from Good to Better!

Whiskey making: the procedure

If we exclude grain handling and aging, traditionally, whiskey is made in three steps:

  1. Mashing (converting starches into fermentable sugars by using enzymes);
  2. Fermenting (converting the fermentable sugars into alcohol with yeast);
  3. Distilling (concentrating the alcohol and harvesting the right flavors).

In order to create the best possible whiskey, both in terms of yield and taste, all steps need to be optimized. The end product is the sum of how the various parts are performed.

If mashing is sub-optimal, the major loss you face, as a craft distiller, is yield. You will create less alcohol. A failing fermentation will, above all, have impact on flavor creation. That’s because over 80% (as a rule of thumb) of taste molecules are made during fermentation. Bad distilling procedures can affect both yield and flavor composition of your new make spirit.

Whiskey making: historically

Historically, whiskey was made in small batches. Small mashes are easy to handle. Small ferments do not generate a lot of heat. Small, copper stills were the norm, because copper was available, affordable, and bendable.

In the 1870’s the industrial revolution found its way into the distilling industry. A lot of the whiskey production became bigger and more centralized. A declining number of remaining distilleries that, each on their own, saw a steep increase in production output.

Small batch traditionally allows for good control and therefore good whiskey …

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Batch size growth associated problems

As distilleries grew bigger, mashing basically scaled up from small batch to big batch, and yield didn’t suffer. Fermentation scaled up from small batch to big batch as well, and this did created a major problem.

Fermentation creates heat, and the bigger ferments created more heat. The warmer fermentations stressed out the yeast and produced multiple unwanted flavor compounds in the base beer, of which sulfur was (and is) the most important.

In short? As distilleries got bigger, mashing didn’t get compromised, but fermentation did. Yield didn’t suffer, but flavors did. Interestingly enough, it took a few more decades for distillers to realize they actually had a problem.

Bigger, uncontrolled ferments generate bad flavors that copper catalyses …

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Houston, we have a problem!

In the 1960’s new metallurgic innovations found their way into the distilling industry. As growing distilleries needed bigger stills, traditional copper stills were replaced with more modern stainless steel set-ups. And guess what? All of a sudden the whiskey they produced had bad, sulfur associated flavors in them!

What had happened, was the following: copper reacts with sulfer. The traditional copper stills had managed to polish-up the bigger, overheated, sulfur-rich whiskey beer! Copper, it turned out, was a really good medicine for a bad ferment.

With SS stills, sulfurs no longer got catalyzed, and bad ferments got exposed …

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The traditional solution

The switch from copper to stainless steel stills brought to light a major problem: bigger ferments created off-flavors. The solution the industry rallied toward, was to switch back to copper stills. The copper catalyzed the sulfuric compounds to below the taste threshold, and the problem was solved. Or wasn’t it?

Bigger ferments, left unchallenged, grow too hot, stressing the yeast into making multiple unwanted flavors. Sulfur is the most significant of those and copper does a good job at cleaning up these sulfuric flavors, and at hiding the poorly managed ferments.

So the distilling industry switched back to copper stills …

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Compromised solution

Using copper stills, to counter bad ferments, is a treatment of effects, not a root cause solution. By allowing for non-optimized whiskey production via copper stills, the following set of new problems occurs:

  1. Uncontrolled, overheating fermentations create more bad flavors than just sulfur;
  2. The copper clean-up during distillation does not polish-up all of those;
  3. Copper stills oxidize, creating copper contaminated whiskey;
  4. Copper stills need extensive cleaning, making for longer working days;
  5. Due to oxidation and cleaning, copper stills need to be replaced in 10 to 15 years.

Even though copper stills are a medicine for bad ferments, they are not the ultimate solution. Bad ferments create bad flavors, and copper does not counter all of them. More so, copper is a heavy metal that is toxic to humans. Due to the reactive qualities of copper, the distillation equipment needs extensive cleaning. This cleaning, as well as the general levels of oxidation, severely hamper a copper still’s longevity.

The iStill solution: a revolution!

That’s why we started proposing a different approach. Here it is. Let’s call it the iStill solution:

  1. Mash in a controlled environment, to achieve maximum yield;
  2. Ferment in a controlled way, to achieve maximum flavor;
  3. Distill in a controlled way, to achieve maximum yield and flavor.

Our iStills are designed to mash with 0.1 degree temperature tolerance. This gives the distiller the opportunity to maximize yield, which helps optimize production quantities.

During fermentation, our technology brings temperature, pH, and SG under control. This ensures that the distiller maximizes the desired flavor development, while mitigating the production of off-flavors.

Finally, the iStills have perfect control over the distillation process. This helps the distiller in optimizing both flavor profile and yield in the most efficient and repeatable way.

iStill gives you the control to make better whiskies …

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Design choices

Because we optimize fermentation, the creation of undesired, bad flavors is minimized. As a result, we do not have to build our stills out of copper. This way, we can deliver a still that is easy to clean, does not cause copper particle contamination in your spirits, and has tremendous longevity.

But if you decide you are going to do your fermentation quick & dirty anyhow, well, please know we have copper waffles that you can insert at the bottom of the column. It takes less than a minute to put them in place. It takes less than 10 seconds to take them out, when the run is done. They have the same surface area as a complete copper column, without the hassle.

iStill copper waffles: well-used …