Pot still hybrid

[myles]

To my mind this is still essentially a pot still but if you wish to disagree and move this post please do so.

My pot still has a 3 foot vertical neck in 2", then a sloped up arm in 2" (with a few extra bends to take in a 2 foot sideways shift) then a longish taper down to the condenser. Now it was OK but I wanted to inprove the heads compression side of things and also boost the output ABV a little bit for doing single runs.

I added 22" of packing to the bottom section of the vertical neck, just above the pot, and higher up near the high spot on the arm I added 6 turns of an external coil around the open 2" pipe. Just to provide a little bit of a cold spot on the wall to induce some condensation. They introduce a bit of reflux in a simmilar way on some of the old onion stills. I added a bit of packing to compensate for the fact that I don't have a 20 foot high conical neck. Oh I also insulated the vertical neck.



Using the same 15% wash for all the runs at different input power levels I have got these results.

With an input of only 500 watts and full rate cooling flow to the external coil my heads start at 88% and the first 2 pints both come off at 87%.

With an input of 3kW the heads start at 81% and pints 1 and 2 come off at 75%. Powers in between have varying results between the two extreemes.
The control with no additional cooling, Heads start at 85%, pint 1 drops to 70%, pint 2 at 68%.

Now I think of this as a pot still with the bonus at low power of being able to compress the heads to 87%. Then either turn off the cooling coil and run as a standard pot still. OR leave the coil ON and run at a power level to give you the collection rate and output ABV that you desire. Lots of variability depending on your power setting.

What do you think.

[LWTCS]

Doing the same thing with my dog dish condenser. I have not yet used any packing.

Olddog seems generally satisfied with the performance of his Frankenstill with packing.

Course now he's into a whole nuther shootin match what with those Evil Twins.

[Slow & Steady]

I have wondered what a fella should call these hybred pot stills... maybe "pot stills +" My 3 Sphere Pot Still operates in the very same range as your design. But much the flavor was gone by the time the vapor got past the copper packing and plates inside the three spheres. That is great when producing a neutral spirit but the "plus" aspect of my design was making for insipid whiskey.

I wanted more flavor than 88% could carry across, even when I pushed the heat input up... the % came down but the flavors were being suppressed so I built a striping head for this still that was a 36" conical neck (4 1/2" tapering to 3/4") to the lyrne arm. For flavor full spirits like Bourbon, Scotch, Rum, and Brandies I perfer the conical tower (no packing) pure and simple. The twice run ABV comes around 70%+ and the flavor profile depends on how deep you run into the tails. In short it runs just like a pot still when I built the conical head.

S&S

[myles]

Thats a very nice looking bit of copper you have there. I read in a post somewhere that once you hit 80% you can forget about flavour. I had not intended to run that high an output ABV for my product. For the heads absolutely. I want to run them concentrated, but not for the hearts. I am thinking that this is for compressing the heads to get sharp cuts, but then to run at a power level that gives me decent flavour AND a good collection rate. Probably only in the 75% to 80% rate.

[LWTCS]

Hey S&S, are you talking about literal plates or theoretical plates?

I have 2 chambers within my orb that (with the dog dish condenser) promote pooling much like a thumper.
The reflux (as such) never makes it back to the boiler. At most, the pooling cups within the orb will overflow back to the Humper Thumper. But never back to the boiler.

[Centimeter]

I think that this is a very wise design. Here's my thoughts on it though (Take it or leave it I guess).

Do you have any sort of collar that funnels the refluxed distillate into the center of the packing? If not, I would definitely recommend this. I wouldn't be surprised if you compressed your heads into the 90% range by doing this with 22" of packing.

Considering you have so much extra surface area from the packing, I'd try to make the lynn arm as short and uncomplicated as possible. Maybe even have it angled down after the vertical section and immediately go into your condenser. If you did this, you could just move your cooling coil to the top of the vertical column to stimulate reflux there.

I'm VERY interested in your future experiments with this design, so please keep us updated!

[rad14701]

Thats a very nice looking bit of copper you have there. I read in a post somewhere that once you hit 80% you can forget about flavour.

Not sure where you heard that but I'm going to disagree... Even with a reflux column, as soon as you start dropping below 95% you will start to have flavor carry over into your spirits... When I want flavor in my spirits I run my column at 88% - 90%, rather than at 93% - 95%, and can get the amount of flavor I'm looking for in either reflux or combo still mode...

[myles]

Do you have any sort of collar that funnels the refluxed distillate into the center of the packing? If not, I would definitely recommend this. I wouldn't be surprised if you compressed your heads into the 90% range by doing this with 22" of packing.

Considering you have so much extra surface area from the packing, I'd try to make the lynn arm as short and uncomplicated as possible. Maybe even have it angled down after the vertical section and immediately go into your condenser. If you did this, you could just move your cooling coil to the top of the vertical column to stimulate reflux there.

I'm VERY interested in your future experiments with this design, so please keep us updated!

Sure do Centimeter, I used the same technique on my VM head, cut down reducing couplings inside a straight end feed connector. Like this.




I do see your point, but I had very good reasons for that strange arm. It takes in a 2 foot sideways shift and adjusts the angles so that my condenser is above the work surface, and parallel to it. You are right though. I have an empty void above the packing in the neck, and if I was not bothered about the sideways shift, that would be where I would put the coil.


Note photo taken before I added the coil and insulated the neck.

I have a longish tapered arm leading to the condenser to try and loose a bit of heat by natural convection. It takes a bit of the load off the condenser. Not neccesary, but convenient.

[Centimeter]

Goodness...

You should call that thing Goldberg. Anyhow, props on such a neat looking still!

It seems to me that your long tapered arm would strip out a bunch of flavor. I understand that you want to make it easier on your condenser, however it's also giving rise to a rather significant temperature gradient which may strip a bunch of flavor out. Although it's angled down... I guess I'm having trouble visualizing what would happen. So let's say that the temperature gradient in the arm is actually sufficient to fractionate to some degree. Would the vapor phase of each fraction rise or fall? If it falls, then I guess it wouldn't strip flavor out right? If it rises though, it seems like you'd end up losing that particular volatile. I don't know, just brainstorming a bit. Perhaps the people who know what they're talking about could chime in on this? Maybe you could try getting rid of the long arm for a run and seeing if you get the flavor back.

[myles]

Goodness...

You should call that thing Goldberg. Anyhow, props on such a neat looking still!

It seems to me that your long tapered arm would strip out a bunch of flavor. I understand that you want to make it easier on your condenser, however it's also giving rise to a rather significant temperature gradient which may strip a bunch of flavor out. Although it's angled down... I guess I'm having trouble visualizing what would happen. So let's say that the temperature gradient in the arm is actually sufficient to fractionate to some degree. Would the vapor phase of each fraction rise or fall? If it falls, then I guess it wouldn't strip flavor out right? If it rises though, it seems like you'd end up losing that particular volatile. I don't know, just brainstorming a bit. Perhaps the people who know what they're talking about could chime in on this? Maybe you could try getting rid of the long arm for a run and seeing if you get the flavor back.

Slight mix up here.The fractionating bit is only of relevance on the upwards section of the lyne arm as it directs the condensate back towards the boiler. After the high spot in the system EVERYTHING that has got that far, ends up condensed and comes out as product. The business of a lighter or heavier product depends on what is left in the boiler at the end. An upwards sloping arm leads to a 'lighter' product as the heavier flavoured components never get to the condenser.

But this is on traditional onion stills with 20 foot high necks. On our smaller scale stills I don't think there is enough of a temperature gradient to make much difference. I couldn't measure much of a difference between the temperature at the bottom of the neck and that at the high spot. That is why I tried to introduce reflux by adding a bit of packing and some deliberate cooling - to compensate for the lack of height.

[Slow & Steady]

Hey S&S, are you talking about literal plates or theoretical plates?

I have 2 chambers within my orb that (with the dog dish condenser) promote pooling much like a thumper.
The reflux (as such) never makes it back to the boiler. At most, the pooling cups within the orb will overflow back to the Humper Thumper. But never back to the boiler.

Well... I'm not really sure it is correct to call them either literal or theoretical. As you can see in the drawing below the so called "plates" are really a set of progressive reflux collectors that serve to concentrate the vapors, but my use of the term "plate" isn't correct. My comprehension of theoretical plates has always been vague at best, but I do believe that the flavor suppression that made the head best suited to neutrals production was largely the result of the two pounds of woven copper column packing in the first and largest sphere. The conical head that I produced for this still really is far superior for high flavor mashes/spirits.

Because we are talking about flavor "a very subjective topic", I think it best to say, "I expect a lot of flavor from my product". Many might not agree with my assessment of the flavor suppression of the 3 Sphere Design. So I should qualify my statement as an "opinion".

S&S

[LWTCS]

S&S,
I didn't realize you had so much action going on inside your head. Nice diagram.

Although different in execution, there are alot of similarities to my vapor path.

You really must be a discriminating flavor buff. I like a cleaner crisper spirit so I bet your rig make a drink right up my comfort zone.

Have you run the unit minus the packing? Or placed packing higher on the head?
Do you do single or double runs?

Had I seen your diagram before my build I my verywell have a unit much more similar to yours.
Although I'm pretty dern happy with my final outcome.

[Slow & Steady]

S&S,
I didn't realize you had so much action going on inside your head. Nice diagram.

Although different in execution, there are alot of similarities to my vapor path.

You really must be a discriminating flavor buff. I like a cleaner crisper spirit so I bet your rig make a drink right up my comfort zone.

Have you run the unit minus the packing? Or placed packing higher on the head?
Do you do single or double runs?

Had I seen your diagram before my build I my verywell have a unit much more similar to yours.
Although I'm pretty dern happy with my final outcome.

I have not taken the copper packing out, but I'm sure that the flavor would pass through much better if I did. It takes a really long time to push the vapor past that 2 pounds of copper.

Cleaner, crisper is a very good description for the 3 spheres design, if I run it three times it gets a down right bright taste. I can't get the packing higher in the head because the first plate blocks my access to the second sphere. I do double runs except on neutrals I do three with airing time between runs.

S&S

[MudDuck]

Any updates on this?

I want to run them concentrated, but not for the hearts. I am thinking that this is for compressing the heads to get sharp cuts,

I've been thinking about a very short CM column to be used as an enhanced pot still, the goal would be too compensate for the smearing effect that small washes have on cuts (washes would be 3 to 5 US gallons). I was wondering how this is working out in the long run as it is similar to what I had in mind.

[myles]

Well MudDuck I have not run this rig for some time due to other life commitments. I will be reconnecting it to my nice shiny 100 litre keg once I have sorted the heating out. Only intend to charge with 50 litres or so of molasses wash, to leave lots of space for foaming.

Bearing in mind why I was doing this - to introduce variable reflux into the pot still, to compensate for lack of height, I did come up with a way of running it that certainly worked.

I took off the insulation as it was actually complicating things, and the trade off on warm up times was not massive.

For heads compression I run at low boiler power with maximum induced condensate to provide reflux from the coil. This has the desired effect of simmulating the reflux that would be achieved by a lot longer neck. Heads ABV is a lot higher than usual.

Once into the hearts phase I switch off the coil completely and vary the boiler input. Very quickly the packing heats up fully and from then on, has negligible effect. Have not finalised these settings yet and will re-start the trials with the new boiler.

I feel these hybrids are a valid alternative to thumpers (although thumpers are more versatile for flavour enhancement) and it is possible to tune the performance of your pot still quite easily, to establish desired product collection rate and output ABV. It is definitely a pot still and opperates like one.

[MudDuck]

I feel these hybrids are a valid alternative to thumpers (although thumpers are more versatile for flavour enhancement) and it is possible to tune the performance of your pot still quite easily, to establish desired product collection rate and output ABV. It is definitely a pot still and opperates like one.

Thanks for the reply, this part here is pretty much 100% what I wanted to know.

[LWTCS]

I've been thinking about a very short CM column to be used as an enhanced pot still, the goal would be too compensate for the smearing effect that small washes have on cuts (washes would be 3 to 5 US gallons). I was wondering how this is working out in the long run as it is similar to what I had in mind.

Both OD and myself are doing this with the dephlagmater. Just an in-line condenser really.

With fresh cool water and a fully variable heat source, you can dial in your abv pretty dern good.

Got any designs in mind MudDuck?

[MudDuck]

Got any designs in mind MudDuck?

I was thinking along the lines of just adding a pass through tube or two at the top of a simple 12" to 18" pot still column. But note that due to free time limitations this project spends a lot of time on the back burner, so don't hold your breath waiting for updates .

It's good to hear that people are already making this idea work.

[Gobbo]

Thats a very nice looking bit of copper you have there. I read in a post somewhere that once you hit 80% you can forget about flavour. I had not intended to run that high an output ABV for my product. For the heads absolutely. I want to run them concentrated, but not for the hearts. I am thinking that this is for compressing the heads to get sharp cuts, but then to run at a power level that gives me decent flavour AND a good collection rate. Probably only in the 75% to 80% rate.

How is it possible that above 80 percent and there is little flavor? How does that mesh with cask strength bourbons in the neighborhood of 120%... I mean, they have lots of flavor.

[Dnderhead]

"" cask strength bourbons in the neighborhood of 120%... ""
I wish I could do that
that is 120 proof or 60%
here is general guide for aging also about 80% of flavor comes from wood.
Bourbon--55%
malt whiskey- 63-68%
grain whiskey- 68-74%
Canadian whiskey-57%
tequila- 56%
rum--78%

[myles]

Gobbo, Dunderhead has it right. I bet if you got hold of some cask strength borbon - FRESH - as in just as they put it into the cask, you would probably not like it much. For sure it will taste nothing like what it does when it has been in there for a few years.

[Dnderhead]

Miles is right. "in the white" it would be "white dog" more like a vodka with bit of grain or whatever flavor.
witch you mite/mite not like.what I like the best this way is fruit witch makes schnapps. and even so not
at 60% (120 proof). this depends on what I'm doing. for sipping I do drink at barrel strength but for "sessions"
much lower more like 30% or 6o proof.
(just to add most is best is aged at 50-55% at this percent it removes more "flavors" from wood and less tannins.
but do to cost of barrels most distillers age at higher percent.

[LWTCS]

Yes Gobbo, you are thinking proof not ABV.
No such thing as 120%