Thumper Question

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

Moderator: Site Moderator

Post Reply
myles
retired
Posts: 2451
Joined: Wed Oct 15, 2008 11:34 am
Location: UK, in the heather

Thumper Question

Post by myles »

Hi folks,
I am awaiting delivery of a set of new stainless steel stock pots. Going to use the 20 litre one as a boiler, and the 11 litre one as a thumper. Have a lot of fruit to use and am thinking of eau-de-vie and plum brandy.

Anyway back to the thumper – does anyone use a diffuser in the bottom of the thumper to break up the bubbles? Will be using 22mm or possibly 28mm pipe going into the thumper, and had thought of reducing this down and fitting a coil of 15mm pipe full of drilled holes in the bottom of the thumper.

Am thinking that this would work like an airstone in an aquarium – lots of small bubbles might be a bit quieter and more efficient. There will be a slobber box in there as well for protection, so it should only ever be clean vapour going into the thumper so no chance of the holes getting blocked. I know it’s a bit more complex but is it what some other folk have done.

I see lots of people use glass thumpers, can you use 1 gallon demijons for the job? What is the best solution for the glass to metal joint.

Miles
CoopsOz
Distiller
Posts: 1172
Joined: Wed Aug 16, 2006 4:00 am
Location: Didjabringyabongalong

Re: Thumper Question

Post by CoopsOz »

I can't answer your diffuser question as I've never done it, however, in regards to the glass thumper question, I think most use glass (myself included) purely for the novelty of being able to see the distillation take place. Personally, if I were to do it again I wouldn't bother making a thumper from glass and just use a stock pot as you have suggested. Glass introduces a whole lot of unnecessary issues...both sealing problems and also safety fears.
It is most absurdly said, in popular language, of any man, that he is disguised in liquor; for, on the contrary, most men are disguised by sobriety. ~Thomas de Quincy, Confessions of an English Opium-Eater, 1856
Hack
retired
Posts: 904
Joined: Wed Feb 06, 2008 7:45 pm

Re: Thumper Question

Post by Hack »

I have to agree with CoopsOz, although some use glass, I'd stay away from it and stick with your idea of using the stock pot. Even though I have yet to try it, I think the diffuser is a good idea. It's been recommended to me, and I've seen it suggested in a couple of places.

Another suggestion, I'd try to set the diffuser as close to the bottom of your thumper as possible. I've been using water to fill my thumper. I fill it just enough to cover my inlet tube, a couple of inches of water in a 20qt stock pot. Then I let it fill to the equilibrium point with the incoming distillate. I find that the amount of water I start with is still diluting my distillate more than I'd like. The point is, I should probably extend my inlet tube so that it is closer to the bottom so I need less water to start with. And maybe you can avoid this trouble by starting with your inlet closer to the bottom. Maybe run your diffuser parallel to the bottom and as close as possible. I'd probably leave the end of the diffuser tube open so that any remaining vapor that doesn't readily get diffused has a place to go rather than create backpressure in the boiler.
Hawke
retired
Posts: 2471
Joined: Tue Mar 25, 2008 1:39 am

Re: Thumper Question

Post by Hawke »

Using water will dilute strength and pull flavor.
Use wash for more flavor, takes less to bring it into equalibrium with the still.
Using low wines will boost final ABV and equalize the quickest.
It is the very things that we think we know, that keep us from learning what we should know.
Valved Reflux, 3"x54" Bok 'mini', 2 liebig based pots and the 'Blockhead' 60K btu propane heat
myles
retired
Posts: 2451
Joined: Wed Oct 15, 2008 11:34 am
Location: UK, in the heather

Re: Thumper Question

Post by myles »

Just to open this again I have been searching through the old posts to try and find an answer to these:

1. Is there any point in putting on a tapered column / lynn arm on a pot that is going to a thumper?
2. Is there an optimum size column / pipework for a 3kw element on a pot still with respect to flowrates?
3. Does a tapered lynn arm on a small (less than 50 litre) pot still help flavour, (do anything?), or is it mainly to improve the performance of the condenser?
Myles
Hack
retired
Posts: 904
Joined: Wed Feb 06, 2008 7:45 pm

Re: Thumper Question

Post by Hack »

I'll have a go at this.

Someone correct me if I screw this up. In general a tapered line arm is a way to smoothly transition to a smaller diameter condenser. Think of it acting like a tapered garden hose nozzle. The gradual taper to the smaller diameter creates less resistance to the flow which allows a greater flow than an immediate reduction to the smaller diameter.
myles wrote:1. Is there any point in putting on a tapered column / lynn arm on a pot that is going to a thumper?
I'd think keeping the arm coming across the same diameter as the column would be best flow. Next best would be a tapered arm. Worst, would be an immedite transition at the column to a smaller diameter.
myles wrote: 2. Is there an optimum size column / pipework for a 3kw element on a pot still with respect to flowrates?

This doesn't exactly answer. The rule of thumb is larger gives better flow. I'd guess the limit would be whether the element could keep up with the flow rate.
myles wrote:3. Does a tapered lynn arm on a small (less than 50 litre) pot still help flavour, (do anything?), or is it mainly to improve the performance of the condenser?
I'd think it's more about flow rates.
Dnderhead
Angel's Share
Angel's Share
Posts: 13666
Joined: Sun Dec 23, 2007 8:07 pm
Location: up north

Re: Thumper Question

Post by Dnderhead »

close,, but when leaving the still vapors collapse ,taking up less room but you still wont them in contact with the copper/lyne arm until they go to the condenser. on the old scotch/irish stills even the condenser was tapered (of course this whould be almost impossible for us)
stepping down works but not as efficient, scene it causes eddys and some turbulence.
myles
retired
Posts: 2451
Joined: Wed Oct 15, 2008 11:34 am
Location: UK, in the heather

Re: Thumper Question

Post by myles »

A tapered Leibig condenser? Wouldn't that be a treat to put on a still. Found a diagram of an Allihn condenser on Wiki too, that would be a bit of work but a nice challenge. So I suppose the ideal answer would be to taper the arm going into the thumper from the pot, and the arm from the pot to the condenser? Sounds like a lot of work but am sure it would look good.
myles
retired
Posts: 2451
Joined: Wed Oct 15, 2008 11:34 am
Location: UK, in the heather

Re: Thumper Question

Post by myles »

OK I am a bit confused now. Where did that last post come from? Is that on the wrong forum or something?
CoopsOz
Distiller
Posts: 1172
Joined: Wed Aug 16, 2006 4:00 am
Location: Didjabringyabongalong

Re: Thumper Question

Post by CoopsOz »

myles wrote:OK I am a bit confused now. Where did that last post come from? Is that on the wrong forum or something?
Just spam mate......world of warcraft stuff.
It is most absurdly said, in popular language, of any man, that he is disguised in liquor; for, on the contrary, most men are disguised by sobriety. ~Thomas de Quincy, Confessions of an English Opium-Eater, 1856
User avatar
Husker
retired
Posts: 5031
Joined: Thu Aug 17, 2006 1:04 pm

Re: Thumper Question

Post by Husker »

we try to clean up that crap as quick as we can. You can go back to "normal" posting now, lol
Hillbilly Rebel: Unless you are one of the people on this site who are legalling distilling, keep a low profile, don't tell, don't sell.
Usge
retired
Posts: 3243
Joined: Sat Aug 18, 2007 8:22 am

Re: Thumper Question

Post by Usge »

Most stills I've seen that use doubler lyne arm comes straight over, and then down to the (in) for the doubler. Come out same way. I've seen bits of the documentary on Popcorn....I ordered it on DVD. In it, he's putting together and repairing one of his stills for his "last run". Popcorns stills I've seen are usually wide and squat, with tall cap. Thumper usually a wood barrel that looks pretty small next to his pot/tank. The pipe going into and out of the thumper keg was all the same diameter. The interesting part I had never seen before was...he cut notches going up both sides of the bottom of the tube that goes down into the thumper where it sits in the liquid (I believe he used either low-wines or feints). The notches were about 2-1/2 inches high. Don't know what that's for or how it helps things. He claims to do 180 proof runs. Don't know if it's true or not.

My favorite part was them building the still furnace using redclay mud and rocks. Don't get to see that much anymore.
Hack
retired
Posts: 904
Joined: Wed Feb 06, 2008 7:45 pm

Re: Thumper Question

Post by Hack »

The notches are probably to help diffuse the incoming vapor in the thumper juice. This is supposed to help raise proof and help make a smoother product.
Little Lukie
Bootlegger
Posts: 102
Joined: Mon Dec 06, 2004 1:54 pm

Re: Thumper Question

Post by Little Lukie »

If you don't have the cutout when you shove in the pipe it will close off when it hits bottom.This way when it hits bottom the gas has exit route.I use same thing.
Usge
retired
Posts: 3243
Joined: Sat Aug 18, 2007 8:22 am

Re: Thumper Question

Post by Usge »

Thanks Luke. How much liquid do you fill it with? (ie..over the top of the notches?)
Little Lukie
Bootlegger
Posts: 102
Joined: Mon Dec 06, 2004 1:54 pm

Re: Thumper Question

Post by Little Lukie »

I fill 1/3 to 1/2 with mash,or water, or low wines.Mash carries flavor over better,wines gives better alcohol output and water can take tastes that are alittle strong out.
goose eye
Master of Distillation
Posts: 2846
Joined: Wed Oct 25, 2006 3:19 am

Re: Thumper Question

Post by goose eye »

ole boys hard solder pipe in so when makein they solder cross member on inside to hold still before they solder top on. they hold pipe off bottom bout a 2 inches an put a 45 on end of it facein in.
they hold off botom so in case ketle pukes itll help.

so im tole
myles
retired
Posts: 2451
Joined: Wed Oct 15, 2008 11:34 am
Location: UK, in the heather

Re: Thumper Question

Post by myles »

Just to pull this back to the question of diffusers and small bubbles, I read on a post somewhere, and I can not remember where - about putting a screen in the bottom of the thumper, above the outlet. Same principle involved, i.e. break up the bubbles into smaller ones to aid the vapour / fluid transfer. Basic idea is that small bubbles are better than big ones. Just like an aeration stone in an aquarium or the difuser in some bongs. Does anyone bother in practice with their thumper setups?
Hack
retired
Posts: 904
Joined: Wed Feb 06, 2008 7:45 pm

Re: Thumper Question

Post by Hack »

I just went back and skimmed the whole thread. Since I made my first post, I've reworked my thumper and my lyne arms and column. Because I made several changes at the same time it's difficult to pinpoint with certainty what affects what. I increased my column to two inches and added tapered lyne arms, which doubled my collection rate. I reworked my thumper to be self filling and more efficient, which is covered in excruciating detail in its own thread in pot distillation as Double Boiler Thumper Ideer.

As part of the rebuild I added a diffuser to the inlet of my thumper. I think it helps to increase the abv a bit and helps produce a smoother product. I made mine so I can run with or without it, but haven't done a side by side comparison. Like I said I made several changes at once, so it's hard to be certain what exactly has what effect.

One thing I'm sure of, that has a huge effect on final proof, is the amount of liquid, and what kind of liquid you start with in your thumper. I changed the inlet on my thumper so that it comes in the bottom of my thumper, rather than being a tube that extends down from the top. I also made my diffuser so it lays flat on the bottom of the thumper. This has made the biggest difference in final proof of my spirits. My thumper has a water jacket that condenses the incoming vapor before it reaches the thumper, so I can start with it empty. If a person didn't want to bother with a water jacket, bringing the inlet in the bottom and laying the diffuser flat allows for filling the thumper with the minimum amount of liquid needed to knock down the incoming vapor. Then the thumper can fill itself until it starts producing. On my thumper it seems there is a certain level that the thumper wants to fill to that is related to the size of the wash and it's %abv.

With this setup I usually get around 70% abv, after conservative cuts, from UJSM. My last run I added in the heads, tails, and thumper juice from the previous run and got 75% abv after cuts.
goose eye
Master of Distillation
Posts: 2846
Joined: Wed Oct 25, 2006 3:19 am

Re: Thumper Question

Post by goose eye »

id be kinda careful with screen wire if you cookin on pulp/grain . if it pukes you got troubles.

so im tole
Post Reply