I plan to make this a recurring item: Tuesday Tech Talk! A post on how we can advance the noble art of Craft Distilling in general, and iStill equipment in special.
And you are invited. Not just to read, but to react or to participate. Are there things you want to bring up? Innovations you want to share? Just sent me an email and I will dive in!
Today’s topic? Improved catalytic functionality and how it can affect total boiler and still functionality and performance. Mind you, this is not a theoretical discourse! I am working on this as we speak and foresee substantial benefits.
The role of copper while distilling
I have always said that copper is no more than a medicine for a bad ferment. If you create perfect fermentation conditions, hardly any sulfur will be produced by the yeast, and so no copper is needed during the distillation phase. Because that’s what copper does: it reacts (catalyses) with sulfur and can help turn a sulfur rich ferment into a smoother drink.
But then again, not all ferments are created equal and we do not all have the ability to invest as heavily as we maybe should into top notch fermentation equipment. Long story short: copper will always play a role in distilling, since it is a great and cheap cure for drinks that otherwise could end up a bit too hard on the palate.
Our approach so far
I have always thought (and communicated) that a copper still or column is not the solution for sulfur control. It’s like saying that cars pollute … so let’s all start riding horseback again.
Copper stills or columns oxidize, wear, create copper particle contamination, and are a menace to clean. Oh, and they are very, very expensive.
Our solution has therefore been to put copper column packing in the bottom of the column, in a separate catalyst. The copper packing provides all the copper contact. The glass catalyst can be taken out after a run, thus limiting oxidation, minimizing cleaning time, and preventing copper particle contamination of your spirits.
Our packing has a big surface area. In fact, we designed our catalysts in such a way that it can hold an amount of copper packing equal in surface area to a complete copper column.
Now, what if we could increase the surface area of our copper packing? A bigger surface area means more liquid/gas/copper contact … so … we’d need less total packing, right?
I have been thinking about this for years now, but so far all my ideas and sollutions have been fruitless. Here’s why:
- A bigger surface area potentially creates draining problems: higher surface area material holds on to reflux much more, possibly creating reflux pooling and column flooding.
I have etched our current copper packing. It increased the surface area by factor 2, but liquid retention became too high. A no go solution. I have put smaller copper SPP, designed for 2 inch columns, into our bigger diameter columns, etched and non-etched, and I have tried to compensate by making the the catalyst less high. Even though the surface area now increased by factor 3 to 4, I ran into draining problems again. That, and it was a pain to remove the smaller copper SPP from the bigger catalyst. It taught me that what I actually need is an easy to handle, higher surface area catalyst without draining issues.
Towards a new innovation
Higher surface area for more liquid/gas/copper contact meant that a compensation had to be found for drainage problems. The higher the surface are, the lower the layer of copper can be …
… so what if we can take that to a new extreme? What if we can increase the copper surface area so much, that only 0.5 to 1 inch of height were needed for perfect catalytic functionality? For sure, 0.5 to 1 inch of height is short enough not to create liquid hold-up, I have tested that, but can we achieve such an extremely high surface area that less than one inch of catalytic material does the job of ridding your ferment of sulfurs?
Yes we can!
Okay, let me rephrase that: yes, I think we can! We have designed copper with such a huge surface area that less than one inch of copper is needed. This does solve the drainage issues I encountered in my previous experiments.
But that is not enough. The challenge was twofold, remember? The need of less copper (1) and to create a catalytic layer that can be easily added or removed from column or iCatalyst (2). You know what? I think we nailed the second challenge too!
Over the last weeks we have not just been making copper with a ludicrously high surface area, we have also succeeded in manufacturing it sausage style. Sausage style like in “let’s make the packing as a sausage at the exact column diameter, so we can shove it into that column easily. And since we don’t need the whole column to be filled with copper … since we only need less than one inch, a slice of that copper sausage is enough. So lets slice that copper sausage up and create a dozen of less than one inch copper catalysts!
And that’s what we have been doing. Making round copper sausages with ludicrous surface areas and cutting them up in small slices. You can now slide your slice of catalytic material in and out of your column with great ease!
Why go through all the hassle?
Well, here’s why:
- Less height for catalytic conversion means there is more column height left for additional redistillations and/or higher output figures;
- Copper is expensive, if we can make do with less, we save you money;
- No more need to take out the complete iStill Catalyst after a run;
- Instead, you just lift the column an inch with the ELS and pull out your slice of copper and throw it in some alcohol;
- This innovation allows us to put copper catalytic converter functionality on our more simple potstill columns, without adding ELS and/or the iStill Catalyst, lowering the overall price point;
- Retro-fitable: because the Copper Slice (iSlice? Sulfur Filter? Heck, we need a name for this!) fits in our columns and iStill Catalyst like a hand in a glove, our existing customers can take advantage of it;
- Scalable: say you want to make a fruit brandy (usually higher in sulfur content!), you now have the possibility to put in two instead of one slice for twice the contact area.
Where we stand
We are now able to make and manipulate the material. We still need to test it in the column. Not to see if it works. We already know it does. Why we need to do more tests is because we want to achieve the perfect balance between open space percentage (say 80%) and open space size (more and smaller open spaces in the slice or less and bigger open spaces?). Too much Tech Talk for you? Let me put it like this: there is an optimum between porosity and catalytic functionality. Tests will show us exactly where the sweet spot is. When we know, we will start mass production. When will that be? My estimate: autumn 2016.