the modern distiller

Odin on Boiler Design

Odin on Boiler Design

Postby Odin » Sat May 07, 2016 4:57 am

Okay. From posts on other forums I know my thinking is not always appreciated. Where I feel I am challenging traditional ideas, others often feel I deserve the pyre for not accepting what has been "common knowledge" for at least a century and a half.

Well, let's find out what MD thinks about it, because - oops - I did it again. Here's a post on my thinking on boiler design and why round is not the best option. Also posted on my iStill Blog:

ON BOILER DESIGN, AGITATION AND TASTE!

Introduction

This is both a theoretical and a practical post. Theoretical, because I will dive in deeper on how a boiler should be designed to work optimally. Practical, because I have put the theory to the test by actually designing and building, according to those principles, the non plus ultra boiler for the new iStill 500 NextGen.

Boiler design and taste

The role a boiler plays in any distilling device, when maximizing taste is the goal, is twofold:

1. Does the boiler enhance the formation of taste molecules (esters) during distillation?
2. Does the boiler provide these taste molecules to the column in such a way that they can be harvested easily?

I have discussed the second point extensively in a previous post. The summary? A wider, rather than a more narrow, boiler design creates a more stable gas bed above the liquids. A more stable gas bed positively correlates with the columns ability to harvest the right tastes in an efficient and effective way. If you want to read more, please do a search on “boiler design”. As for now … let’s look at the first point: how can boiler design enhance the formation of taste molecules during the distillation process?

Taste formation while distilling

Most of the taste of any taste richt product, like rum, whiskey or brandy, is created during fermentation. Even though the distilling part of the process is more about taking out (Headsy and Tailsy) tastes, distilling can actually add up to 20% of taste. If (and that’s the important word here!), if that boiler enhances the Maillard Reaction as well as the process of esterification.

Esterification is the creation process of taste molecules, also called “esters”. Esters are formed where alcohol and organics meet in a wet and sour environment. Read: where grains and alcohol or molasses and alcohol or fruit and alcohol or berries and herbs and alcohol meet. Water is the medium that helps the organics and alcohol join. Sourness increases the esterification reaction, as does heat.

In plain English? For a boiler to actually help you create more taste, it must have the capability to deal with organics.

The Maillard Reaction is a caramalization process that creates a taste cascade. It is triggered by temperatures close to 100 degrees Celsius (and a few other things) and enhanced by slight temperature differences in the boiler. To get these temperature differences, you need a directly fired still. Indirectly heated stills have perfect temperature distribution and therefore hamper the Maillard Reaction.

Again – and in plain English – you need a direct fired boiler to create taste. A directly fired boiler that can handle organics.

Odin’s teacup paradox

One day, when stirring some sugar into a cup of tea, it struck me: the way agitators and boilers are designed is not right. This is what happened. I had a round glass of hot tea, I poored in some sugar, and I stirred quickly. Where I expected the sugar to be distributed more evenly throughout that glass of tea, it actually didn’t. Instead, I could witness two things happening:

A vortex was created, pushing the liquid down in the center while pushing it up near the edges of the glass;
The sugar gathered in the center of the glass and did not disperse evenly at all.
Like this:

IMG_5664.JPG


Stirring at high rpm in a round glass or boiler creates a vortex and centralizes particles. A vortex is bad, because it disturbes the gas bed above the liquid and because it severely limits the maximum filling charge a boiler can take. Particle centralization (instead of perfect particle distribution) potentially creates burn issues.

The NextGen boiler design

I wanted the NextGen boiler to solve my teacup paradox, and this is what I did: I created a flush square design. The flush part helps circulation, where 90 degree angles would have hampered it. And the square design actually breaks up the vortex. And more! The four corners of the flush square boiler design act as “chimneys”, sucking up grains from the bottom and redistributing them to the top.

Instead of a vortex, with centralized particles, the new boiler design and agitator create a stable liquid bath with perfect particle distribution!

Like this:

IMG_5665.JPG


Movie …

As the proof of the pudding is in eating, the proof of perfect boiler design and agitation is in seeing it happen before your own eyes … so here’s a short movie. It will show you how the new boiler design and agitator work together to prevent vortex formation and particle centralization. If you look at the four corners of the boiler, you can even see the chimney effect:

https://www.youtube.com/watch?v=X_nw7oVDk_M

Regards, Odin.
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"Great art is created only through diligent and painstaking effort to perfect and polish oneself." by Buddhist filosofer Daisaku Ikeda.
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Re: Odin on Boiler Design

Postby Zymurgy Bob » Sat May 07, 2016 8:34 am

Can't speak fpr others, but I certainly appreciate your thinking and experimentation. Too often, home distillers get caught up in "purity" of the product, purity meaning to me "absence of flavor". For me, most of what I distill is all about flavor, and I appreciate any information I can get. Thanks.
Zymurgy Bob, a simple potstiller http://www.kelleybarts.com/zymurgy-bob-books/making-fine-spirits/

You can make whisky in a reflux still, you can make vodka in a potstill,
and you can eat chicken noodle soup with a crescent wrench. But..
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Re: Odin on Boiler Design

Postby aliced » Sat May 07, 2016 3:35 pm

Another "Storm in a Teacup" Odin?

OK, so putting your "wider is better" theory behind us for the moment, what I would be interested to learn about your latest brainwave is why you think that having "perfect particle distribution" would improve flavour?

Got any science or established fact to back that up champ?
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Re: Odin on Boiler Design

Postby Odin » Sat May 07, 2016 5:06 pm

aliced wrote:Another "Storm in a Teacup" Odin?

OK, so putting your "wider is better" theory behind us for the moment, what I would be interested to learn about your latest brainwave is why you think that having "perfect particle distribution" would improve flavour?

Got any science or established fact to back that up champ?


... because it allows me to do on the grain / fruit / berries distillation with a direct fired still.

Regards, Odin.
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Re: Odin on Boiler Design

Postby res » Sun May 08, 2016 6:30 pm

I prefer to think of tradition as a well worn pathway, something to guide those without the time, inclination or creative endeavour to seek a alternative route.
Rather than a corral that forces a specific direction.
I guess that's a flowery way to say there’s nothing wrong with trying new ways. If you get lost in the wilderness or find a new a better path tradition will move forward as it always has.

For my part I'd love to hear more on direct heating as it applies to washes with higher amounts of solids.
I'll take your word for it that a square boiler has a positive affect on ester formation but you lost me here

Odin wrote:Particle centralization (instead of perfect particle distribution) potentially creates burn issues.
Regards, Odin.


And here

Odin wrote:... because it allows me to do on the grain / fruit / berries distillation with a direct fired still.
Regards, Odin.


How does diverting solids to the corners as apposed to the center help with burn issues? :confusion-confused:

Cheers.
Success is not final, failure is not fatal: it is the courage to continue that counts.
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Re: Odin on Boiler Design

Postby bigfoot » Mon May 09, 2016 3:29 pm

Same question from me.
I know minuscule amounts about a lot of different things and I don't know a lot about any one thing - enough to have me ask silly questions really.
I like the idea but can't really understand it either -
I would have thought thermal heat transfer would see the internal corners as the hottest (much much hotter) part of the boiler.
Ever used a square pot or pan, the edges gather the heat very quickly - and I burn me eggs on the outside. Now the square pan is for beltin the dog, not cooking :laughing-rolling:
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