Bubbler as a Pot Still Design

[Brendan]

So i'm building my bubbler as a completely modular unit so that I can use it for several configurations.

One of these will be as a pot still (I know you often don't need to strip with a bubbler, but I will still be using it for various things and exprimenting).

I'm unsure as to the configuration of the 180 degree bend above the reflux condenser...obviously we all know that 2" works fine for a bubbler, and I am using a 2" shotgun condenser as the product condenser.

My concern is that when removing the plates and reflux condenser, to use as a pot still, that reducing to 2" before the 180 degree bend will slow down the output when using as a stripper.

I currently run a 3" pot still, which is a 3" column and a 3" lyne arm which reduces on it's way down. With the bubbler having a 4" column, what effect would the 2" reduction at the top of this have on the speed of the output? Would it act as if the whole column was 2"...I would obviously expect some more passive reflux (kinda like a mini boil ball), where the restriction brings in the wall diameter, and there is some reflux on the walls returning liquid back down the column.

If the stripping output would be slower than my current 3" pot still, I would make the bend larger and reduce on the downward toward the product condenser....

I have the capacity to use any size 2", 2.5", 3"...and 4" I guess if needed...

Here's a diagram of what I mean side by side:

Bubbler_Pot_SideBySide.jpg

Any feedback would be greatly appreciated :handgestures-thumbupleft:

[kelbygreen]

I would say its fine and I would say use your current pot still lol

I have 3" going into 3/4 before the liebig and that strips fast. Fast enough I dont dare put any more heat into it as it comes out about 35 deg into the jar with a 1.8m liebig

I doubt your output will be noticeably different it will just travel down the 2" prob twice as fast as it was in the 4". I think thats where mine fails as it has 3" to 3/4 in the liebig it is speeding the vapour up that even with the 1.8m it hasnt got a big surface area like a shotgun condenser so it comes out hot.

[Brendan]

Yeah dude but the point is having a restriction while the vapour is still going up.

You make it sound like you're talking about once the vapours have crossed over the high point in the lyne arm and are heading down?

[kelbygreen]

yeah see your point. but it shouldnt have to much effect as the vapour around it should be the same temp so it will only be the small amount touching the walls that may condensate.

Mine reduces right on the bend so anything that condensates will run back to the boiler anyway as it cant run up hill lol. Also I got a longer column then most pots so that would make it worse. Still I can pump it out where I like it.

You will still have the same issue in the bubbler as well if there is one but it is in reflux anyway so shouldnt matter maybe need a little more heat if any.

To me I cant see a issue, one other thing is will the PC keep up with it and also have you got enough energy in heating to max it out. I would be using the pot still you have as I doubt you will be running it like that heaps anyway once it all done :handgestures-thumbupleft:

[Sam.]

I am assuming you are using a 2" shotgun condenser?

Don't reckon you would notice too much of a difference between the designs you have shown.

I would personally trend to reducing in increments just before your PC but again would it make THAT much of a difference :think:

[Brendan]

Yeah I agree Sam with reducing in increments...which I have done myself on the downward arm on my 3" pot still.

Kelby, the point is not really the temp and the reflux created...it's the column with 4" of vapour being pushed up, and then a 2" restriction before it goes over the lip...this may have the potential of acting completely like a 2" column which is a waste... :think:

[emptyglass]

All you need do is stop the reflux condenser from working (no coolant will do it) and it will behave like a pot still, for the most part.
Take the plates out and it is a pot still.

I get 8 litres an hour out of a 2" pot still spirit run, but I only get 3 litres an hour out of a bubbler. The speed comes from the quality and concentration of the product first time round.

I agree with KG, probably best just run the 3" for pot still duties, but its up to you.

With the restiction, you are making a pot still, so the less restiction and sudden changes it has, the better.

[Brendan]

Thanks for replying EG...I think I mustn't be getting my thoughts across properly.

I plan to set it up completely as a pot still...I will remove all the plates and the dephlegmator, making a pot still as you mention.

I don't want it to be any slower at stripping than my current 3" pot still. If using 2" elbows at the top will make it behave as if the entire column was 2", I will use bigger elbows...

So in the diagram, the first pic is the bubbler design (with 2" bends)...the other 3 pics are the options when taking it's running as a pot still into account...

Sorry for the confusion 8-} It's more a vapour speed/volume theory question really...i'm not sure if the vapour speeding up for the restriction theory applies here and I get the same output as if the bends were 4", or if they greatly reduce the output...

[Sam.]

Thanks for replying EG...I think I mustn't be getting my thoughts across properly.

I plan to set it up completely as a pot still...I will remove all the plates and the dephlegmator, making a pot still as you mention.

I don't want it to be any slower at stripping than my current 3" pot still. If using 2" elbows at the top will make it behave as if the entire column was 2", I will use bigger elbows...

So in the diagram, the first pic is the bubbler design (with 2" bends)...the other 3 pics are the options when taking it's running as a pot still into account...

Sorry for the confusion 8-} It's more a vapour speed/volume theory question really...i'm not sure if the vapour speeding up for the restriction theory applies here and I get the same output as if the bends were 4", or if they greatly reduce the output...

If you run it as a pot and have it 4" up to the top, then into say 2" it should't matter. You may have to have more cooling capacity because its going to be coming through faster or a bigger condenser (which I doubt)

Well in summary I don't think you have an issue here at all :handgestures-thumbupleft: It will work fucking awesome :handgestures-thumbupleft:

[Brendan]

I guess my question if this is the case, for those vapour theory nerds :ugeek: ...

What is it that makes a 3" or 4" pot still faster than a 2"?

If vapour theory says it just speeds up for those restrictions, just like a 2" opening in the keg into 4" column...shouldn't a 2" or 4" column have the same output speed, and it only be dependent on power applied to the boiler?

Just something that's got my theory knowledge stretched a little... :doh: Trying to make sense of it.

[emptyglass]

:text-+1: what sam said

You have to reduce the diameter somewhere. The gentler this can happen, the better. The pic on the right would be the choice, but if your looking under every rock for performance, the reducers should be long and gently tapered. Possibly even go for 4" elbow (or swept bend) on top of the column and reduce from there.

All I was saying is that you can make a bubbler behave like a pot still, even mid run, not that you would want to. It would be up to you to do the experiments and work out if the gain you got by stripping the guts out and changing heads is worth it over just turning the reflux condenser off.

EDIT; to quote a quotable quote, "height = purity, diameter = speed."

[Brendan]

Thanks EG...I probably didn't mention...the size that I go with for use as a pot still, will be the one and only used for the bubbler...there will be no head changing. I must have been a bit vague.

Not sure about leaving the plates in...I guess the bottom line is I want to design my bubbler to be able to strip at the same or faster output than my 3" pot still...whether or not that means removing the reflux condenser and plates to use the width of the column.

Any reducing will be tapered of course, just a point of reducing to 2" before or after the point where vapour starts going down :D

So if I choose 3" or 4" as the optimal 180 degree bend for use as a pot still...that's what the bubbler will have :handgestures-thumbupleft: (I cant see a roblem with it being too big for the bubbler, just too small for the pot).

[emptyglass]

I gotta ask mate, why the interest in still being able to strip?

Seriously, you won't need to for the bulk of products you can make through a bubbler. I'm struggling to think of why you'd need to.

[Brendan]

Okay...well for starters, I want a pot still to do comparisons between the bubbler and multiple pot distillation experiments, but would like to replace my other pot still...make use of the 4" column.

But say for an all grain, single malt whisky...yes you can just run it through the bubbler once...however it is well reported that there are vast differences between once run whisky through a bubbler, and whisky stripped and then run through a plated column...

Most artisan distillers strip their whisky wash, and then run second distillation spirit run through a 4 plate column....so why would it be any different at home?

This is the main reason...so I guess you could summarise with experimentation...then I can answer similar questions in the future :handgestures-thumbupleft:

[MacStill]

I like your thinking Brendan, I've run low wines through my bubbler and the rum I got from it is some of my best yet :handgestures-thumbupleft:

[kelbygreen]

you are making a 6 plate bubbler arnt you? So you will distill it 6 times rather then the 5 time with a strip run and a run threw 4 plates?

Worth a try but I would be using the pot you have to test it as if its not worth it then you have saved your self time and money. If its worth it then report back as I cant see it being a hell of alot better for the difference.

I wouldnt go out there waste money if not needed. Some one prob has trialed this and can tell you (I hope) as I cant see the reason behind it

Edit: well mac says his rums better like that so might be worth it. But stilll transforming your bubbler to a pot, unless your selling your pot I wouldnt bother. Make it to suit future upgrades if you want 4 " all the way threw do it. It wont hurt its just the cost. If I could do it I would but I cant so cant comment on your situation :)

[Brendan]

Although bubblers are touted as the one run machines, I don't want to shatter anyone's dream...

Just seems most commercial distilleries with a plated column (usually bubble cap plates), still tend to use them as a second distillation only.

They seem to bypass the column and do a stripping run of low wines first... :think: I like to replicate the pro's...although all credit to innovation and new ideas.

edit: I am building 6 modular pieces Kelby, however...It will be:

6 plates with a packed section for neutral
Strip run as a pot, then 4 plate spirit run for whisky (and maybe rum)
And will be experimenting with other variations to compare...

[kelbygreen]

yeah thats cool . I am not saying dont do it, I was looking at it my way as I cant afford to play around with stuff so tend to stick to the known.

I think its good you are going out there and hope to see the differences as I can go that path but doubt I will use my bubbler for a pot as I have one I am happy with :D

seems there is a improvement in it so give it a go I think!

[emptyglass]

That sounds fair mate.

Just make it with triclamps on every join and its future proof.

Sounds like you're planning to make the good gear :handgestures-thumbupleft:

[Brendan]

Only the best EG ;-)

And yes, it's tri-clamps everywhere! I don't want to build another column, and have the option to add/remove plates, and change dephlegmator, and product condenser. :D