Pot still technology?

Simple pot still distillation and construction with or without a thumper.

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bluc
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Pot still technology?

Post by bluc »

Ok so theres thumpers and onions and vertically angled lyn arms, am i right in thinking that these are all types of reflux inducing devices? I realise there are other uses for a thumper like adding flavour.

And how do these work at seperating the fractions and compressing heads and tails.
Does one create a "cleaner" product than the other. I dont mean higher proof i mean less smearing of fractions.
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Re: Pot still technology?

Post by ShineRunner »

I can address a little of this. I know onions and long tapered Lyne arms are meant to induce a little reflux to a pot still, but the general concensus on here is that they're of little use on the hobby scale. I don't think they change the fractions or smearing at all, but I have no actual experience with them.

As for a thumper, it doesn't really cause reflux, but it can be considered a partial redistillation. Think of it as a single plate on a pot. Read up on how they work, but it's basically like 1.5x run. As for separating fractions, I can say that when I started using my thumper, I noticed a couple things. The proof tended to stay a little higher for longer and then dropped quickly, instead of a steady slow decline in proof. Second, I find that my cuts are more distinct than without the thumper. Almost always within 1 jar that is clearly not wanted and the next is good.

Try some things out and let us know. This is how our hobby is advanced..

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Re: Pot still technology?

Post by Bushman »

When you slow down flow we consider it passive reflux your not really compressing your product as through the use of a reflux condenser.
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Re: Pot still technology?

Post by still_stirrin »

bluc wrote:...how do these work at seperating the fractions and compressing heads and tails...
The onion top uses pressure differences to induce a touch of passive reflux, or more appropriately "condensation".

Reflux, by definition is a combination of condensation and reboiling of the condensate by rising vapors. The process of reflux separates the vapor constituents with higher boiling points from those which are more volatile (lower boiling points). Active reflux uses a reflux condenser at the top of the column to condense the rising vapors so they fall back through the packing, which is heated again by the rising vapors. The condensate will again boil as the heat is transferred back to the condensate, this time with the volatile constituents separating (slightly) and once again rising. This process continues over and over thereby fractionating the higher (lower boiling point) alcohols from the lower constituents (H2O and alcohols).

The onion top makes use of "the ideal gas law" in that pressure is inversely proportional to density (assuming constant temperature and mass flow). So, when the hot vapors rise to the onion's dome, the "ball" section, the pressure drops slightly as the vapors expand to the increase in the crossectional area. As the vapor expands, the static pressure lowers (ideal gas law), and part of the vapor will drop below it's saturation temperature (liquids boil at a lower temperature at higher altitudes, where the air pressure is lower), causing the "heavier" constituents to condense (usually along the walls of the dome). The purer, more volatile portions of the vapor will continue to rise along the conical top and the lyne arm, all the while cooling slightly as the vapors transfer heat to the walls of the still head. What happens here is that the vapors cool slightly and only the purer, more volatile vapors proceed on to the product condenser.

The "doubler", or thumper uses the condensation of the vapors up through the liquid thumper charge to initiate the same, or similar condensation and reboiling of the vapors. As stated here already, this is parallel to a single plate in a flute, or plated reflux head. As the thumper comes up to temperature, it will tend to accumulate the heavier (less volatile) constituents of the vapor. It will also sink (absorb) some of the heat carried in the hot vapors.

"Smearing" is dragging along of the volatile constituents (fores & heads) as well as entraining some of the heavier constituents (tails). Aggressive boiling will cause the tails to carry over sooner than anticipated by the boiling temperature of the mixture.

Here's the bottomline....if you want a lot of flavor, then some smearing is your friend. If you're after higher refinement, then multiple redistillations is your target.

The onion top (alembic still) is great for full flavored spirits, especially brandies, where there are flavor components in both the late heads and early tails (fruit flavor & aroma).

The thumper (doubler) is a great tool for producing whiskies in a single pass and get product up to cask strength. The thumper in conjunction with the potstill will produce a full flavored spirit, especially with all grain mashes.

Whew...I'm out of breath. I hope this dissertation helped you a little.
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Re: Pot still technology?

Post by still_stirrin »

Hey bluc,

You asked a similar question a year and a half ago. You did get some good answers then...did they not help you...or is this just a followup study?

Reference: http://homedistiller.org/forum/viewtopi ... 6#p7369426
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Re: Pot still technology?

Post by bluc »

Awesome posts fellas thanks.
still_stirrin my first post was asking about thumpers this one was more about comparing the technologies used by pot stills. Been trying to get straight in my head why a thumper/onion/angled lyn arm is used rather than just adding some form of rc. Slowly sinking in how things work.

Money is short and I am trying to work out the best route for me to take. I want to do single runs seems a plated still is the best for the job, but they are expensive and something in my gut keeps dragging me towards a pot with a thumper or hybrid pot with some form of rc but not sure that either will produce as good a spirit as a strip then spirit run through a pot...
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Re: Pot still technology?

Post by still_stirrin »

buildin' or buyin'?

I think if $$$ don't matter, then a plated CM might be the tool. But if you're finance limited, building a potstill + thumper is the closest tool to put in your toolshed.
ss

edit to add - daydreaming is "dreaming". You can dream all day, but putting plans into motion is taking action.
Last edited by still_stirrin on Sat Apr 01, 2017 5:13 pm, edited 1 time in total.
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Re: Pot still technology?

Post by RedwoodHillBilly »

I also think that it depends on what you are trying to make. For flavored spirits, a pot still or a pot / thumper will serve you well. For neutrals a CCVM isn't a bad choice. For flexibility, I would go with a pot / thumper and perhaps add a CCVM column. This would allow you to make almost anything that you would want to make at a fairly low cost. If money is really tight, forget the thumper.
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Re: Pot still technology?

Post by still_stirrin »

What RWH said is good advice. Start easy and add when & what you can. But start already. C'mon in...the water's fine.
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Re: Pot still technology?

Post by Truckinbutch »

Went slow and easy with a keg pot/keg thumper . Nobody that's had a drop of what I produce has declared it unfit to drink .
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Re: Pot still technology?

Post by bluc »

I should post more info... i have been potstillin for about 3 years but looking to next upgrade. Onion thumper reflux condenser or hybrid still/plated colum. I get that a plated colum is top of the stack but i would be happy if i could do a single run and end up with something as good as a two pass and cuts pot still run..maybe a pot thumper with single plate an rc or a pot and thumper or a hybrid reflux/pot still. Looking for as much info as possible to make an educated desicion :thumbup:
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Re: Pot still technology?

Post by BDF »

Starting by getting yourself a keg as a boiler will allow you to run now as a potstill with a simple head going straight to a condenser, but also be versatile enough to upgrade or swap out still heads in the future if you want to try other things.
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Re: Pot still technology?

Post by googe »

There's something in the way rising vapor acts in regards to open area before being condensed, what it is is something I don't know :lolno: , but would.like.to.
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Re: Pot still technology?

Post by BDF »

googe wrote:There's something in the way rising vapor acts in regards to open area before being condensed, what it is is something I don't know :lolno: , but would.like.to.
Conjecture here, but since vapor is rather compressible, having a larger vapor section might cushion to absorb sudden pressure changes that might disrupt your boil. Avoiding a similar problem to the case where cooling too fast in your condenser can cause huffing.
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Re: Pot still technology?

Post by Pikey »

googe wrote:There's something in the way rising vapor acts in regards to open area before being condensed, what it is is something I don't know :lolno: , but would.like.to.
Still stirrin has given an explanation at para 3 post 4 above. 8)

[Edit - I'd be interested in learning more about that too - is there a link ? ]
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Re: Pot still technology?

Post by Kareltje »

bluc wrote:I should post more info... i have been potstillin for about 3 years but looking to next upgrade. Onion thumper reflux condenser or hybrid still/plated colum. I get that a plated colum is top of the stack but i would be happy if i could do a single run and end up with something as good as a two pass and cuts pot still run..maybe a pot thumper with single plate an rc or a pot and thumper or a hybrid reflux/pot still. Looking for as much info as possible to make an educated desicion :thumbup:
To me it seems you seek certainty where there is none.
There are a lot of ways to get to some result or to make some product, each with a different taste/effect/efficiency, but no one better than the other.
Look how many recipes for gin there are. All different in ingredients, in time of maceration, in percentage of maceration, in placing of the herbs etc. All these variables have a influence on the final product. But whether you like the taste of the product is a matter of taste.

If your budget is tight, you can start with a simple still (you already did) and make your extentions exchangeable. The boiler and the condenser can be used always, the difference is in the path between these.

I think you are afraid to make choices you might deplore later. But when your pieces are exchangeable, you can almost always use them.

Just as BDF already said.
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Re: Pot still technology?

Post by Kareltje »

BDF wrote:
googe wrote:There's something in the way rising vapor acts in regards to open area before being condensed, what it is is something I don't know :lolno: , but would.like.to.
Conjecture here, but since vapor is rather compressible, having a larger vapor section might cushion to absorb sudden pressure changes that might disrupt your boil. Avoiding a similar problem to the case where cooling too fast in your condenser can cause huffing.
Recently I heard the huffing and found it useful audible information. But why is this rate of cooling too fast?? I found it very convenient, because the sound meant the cooling occurred very early in the condenser.
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Re: Pot still technology?

Post by BDF »

Kareltje wrote:
BDF wrote:
googe wrote:There's something in the way rising vapor acts in regards to open area before being condensed, what it is is something I don't know :lolno: , but would.like.to.
Conjecture here, but since vapor is rather compressible, having a larger vapor section might cushion to absorb sudden pressure changes that might disrupt your boil. Avoiding a similar problem to the case where cooling too fast in your condenser can cause huffing.
Recently I heard the huffing and found it useful audible information. But why is this rate of cooling too fast?? I found it very convenient, because the sound meant the cooling occurred very early in the condenser.
The huffing I'm talking about causes vapor to escape the condenser, which is flammable. In addition, sudden pressure changes alter the vapor pressure over the boiling wash allowing higher temperature volitiles to come over earlier, basically increasing smearing between heads/hearts/tails.

Doesn't matter much for stripping runs, but is to be avoided for spirit runs.
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Re: Pot still technology?

Post by Kareltje »

BDF wrote:
Kareltje wrote:
BDF wrote:
googe wrote:There's something in the way rising vapor acts in regards to open area before being condensed, what it is is something I don't know :lolno: , but would.like.to.
Conjecture here, but since vapor is rather compressible, having a larger vapor section might cushion to absorb sudden pressure changes that might disrupt your boil. Avoiding a similar problem to the case where cooling too fast in your condenser can cause huffing.
Recently I heard the huffing and found it useful audible information. But why is this rate of cooling too fast?? I found it very convenient, because the sound meant the cooling occurred very early in the condenser.
The huffing I'm talking about causes vapor to escape the condenser, which is flammable. In addition, sudden pressure changes alter the vapor pressure over the boiling wash allowing higher temperature volitiles to come over earlier, basically increasing smearing between heads/hearts/tails.

Doesn't matter much for stripping runs, but is to be avoided for spirit runs.
That is quite another huffing I am talking about. At a 12 % mash running with great cooling at the end the huffing blowed out a burning candlestick, but without risk of fire.
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Re: Pot still technology?

Post by BDF »

Kareltje wrote:That is quite another huffing I am talking about. At a 12 % mash running with great cooling at the end the huffing blowed out a burning candlestick, but without risk of fire.
If either increasing your power input, or decreasing condenser waterflow fixes it, it might have the same underlying cause. The transition from vapor to liquid happening fast enough to cause sudden vapor collapse and pressure differentials which may still cause smearing. General advice I've seen around here is you want as gradual a transition from vapor to liquid as possible along the length of your condenser to have cleaner separating between your cuts.

I think I've read that reductions in pipe size happening to quickly can also cause or contribute to this, such as transitioning from 2" pipe to 1/2" pipe in a single step.

Though I'm a newbie myself.
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Re: Pot still technology?

Post by Truckinbutch »

You got to learn how to drive what you have . It's not self driving technology . The human element is the deciding factor .
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