adding a cooling to the top of a pot still

[biker geek]

Hello All,
I have soldered up a pot still head with a 30"x2" riser(column), and I found a bunch of 3/8" soft copper tube from another project. I am considering soldering about 10 wraps of 3/8 tube to the top of the column to make the still head a little more versatile. I realize that CM stills are not the favorite around here, and that it would be difficult to make high proof neutral with this setup, but I thought it would be interesting to try using a small amount of reflux with 3 scrubbers(for example) for a flavored spirit in a single run. Is it worth the trouble?

[Usge]

Lets clear up a bit of misunderstanding here. There is nothing wrong with Cooling management in and of itself. Each type has it's own pluses and minuses. CM works darn well compressing tails as it continually squeezes them harder and harder (given even water temp). What fell out of favor was the older "designs" of them...the ones with the tubes through the column into the liebig top and bottom. There are a few here who built highly advanced and tuned CM stills...with temp controls, etc. for refluxed runs. The biggest problem with CM is getting the ratio of heat to cooling right. And from there...maintaining it...given fluctuations in water flow, temp, etc. There are various ways to set this or get to know it...as it could vary still to still depending upon how your cooling is setup and how much heat you are running. But, I would mention...the notion that you can only control these stills by water flow (which is fiddly at best) is not accurate. You can set the water flow by finding min/max settings...and then use "heat" (or power management) to adjust the reflux ratio. (*ie., you set the water flow..then turn up the heat till you get a drip coming out..as opposed to lowering the water flow till it drips...which is fiddly and takes a long time to wait between adjustments for it to settle).

Your idea will work fine. And since you can use it, or not use it...simply by controlling water flow to it....it won't hurt your capaibilty to run this as a potstill either. (win-win). Some people prefer the taste of single run whiskey (run at higher proof on a single run). So, it's certainly worth experimenting with. If you aren't sure it's something you want to keep....just wrap the tubing tightly around the outside of the column at the top (1/4 OD probably work better for that)....maybe put a small tack of solder on the bottom rung to hold it up... That way if you decide not to keep it..you can easily remove the whole thing in one shot. A single wound bit of 3/8" coil in the top would work too. You might also want to check out the information that Prariepiss put up about running/optimizing this type of still.

[Prairiepiss]

Couldn't agree more with Usge.


I am wondering about your placement of the coil? Your saying at the top? What exactly are you meaning by the top? Top to me is the very top which would be above the takeoff. It would ne best placed slightly lower then the takeoff. Depending on your pot still design? Generally I would say one to two inches below the takeoff is a good spot. I'm in the thinking that things are still separating a little above the reflux condenser on a cm still. So they need a little room for it to happen.

As far as coil size. I have 8' of 1/4" coiled in a 2" id coil about 4" tall in mine. The differences is my coil is in the vapor path. So its more efficient. Where yours will be on the outside of the column. So you will need a little more then what I have. The 3/8" tubing will add a little more mass and able to flow more water. So it will help. I would start out longer. And test it. Because you can always cut some off. It's a lot harder to add some to it. Without making a new. If I were to try it. I would start with a 6" tall coiled section. Below the takeoff. And Scrubbers in the condenser section will increase its efficiency. But try to keep the small space above the condenser open with no packing.

What will you be using for heat?

[Bushman]

I agree with your comments Usge, however everyone learns to run their still to make it more efficient. With mine I found playing around with the heat is more difficult and water flow easier to manage. I have electric and the slightest tweak with heat can throw the equilibrium off. Also having clear water lines make it easy for me to dial in the right amount from knowledge gained on multiple runs. For heat my start up is at 22 amps then when my thermometer on the boiler reaches 190 I dial it down to 18 amps. From here with a 6" long dephlagmater I can run total reflux for an hour plus till I reach equilibrium. I then only and this is slightly tweak my water line to the dephlagmater and wait a couple minutes And then tweak again until I get the drip I am looking for in my heads collection.

Like I said everyone's still is a bit different. I have 3 sources to restrict the water flow, one to the dephlagmater, one to the shotgun condenser, and one with a nozzle control where it attaches to my inlet line. This method is easy for me to dial in and control even on my well.

[Prairiepiss]

I have found water flow adjustments to be a slow process. And not very precise. One small adjustment can take a minute to get the full outcome. And change things considerably.

Where heat adjustments were almost instantaneous. And way more precise.

So I use the water adjustments for the main settings. Then fine tune it with heat adjustments.

Granted I only use my parrot for the only indicator of where I am. So I mite have a different view if I had thermometers.

But with the parrot I adjust the water flow and it takes time for the hydrometer to show a change. And its usually a swift big change. And takes anywhere from 5 seconds to 30 to get stabilized. That's with a needle valve for the adjustments. But when I adjust the heat. VIA electric controller. The hydrometer almost moves with the adjustments. Maybe a one to 5 second lag.

But yes I'm sure every still is different. And finding which works best for you is an experiment. But I think we can all agree they are best ran by adjusting both coolant flow and heat input. You can't truly rely on just one of them. Or you will never find the best potential of your still.

[Spamgel]

i was considering doing this also. Would building a jacket outside the column make it easier to control?just like a liebig.

[Bushman]

I have found water flow adjustments to be a slow process. And not very precise. One small adjustment can take a minute to get the full outcome. And change things considerably.

Where heat adjustments were almost instantaneous. And way more precise.

So I use the water adjustments for the main settings. Then fine tune it with heat adjustments.

Granted I only use my parrot for the only indicator of where I am. So I mite have a different view if I had thermometers.

But with the parrot I adjust the water flow and it takes time for the hydrometer to show a change. And its usually a swift big change. And takes anywhere from 5 seconds to 30 to get stabilized. That's with a needle valve for the adjustments. But when I adjust the heat. VIA electric controller. The hydrometer almost moves with the adjustments. Maybe a one to 5 second lag.

But yes I'm sure every still is different. And finding which works best for you is an experiment. But I think we can all agree they are best ran by adjusting both coolant flow and heat input. You can't truly rely on just one of them. Or you will never find the best potential of your still.

My adjustment time or lag time is about the same heat or coolant but with my rig I find the results more drastic with heat. In other words a light tweak on heat and after waiting a minute the change is more drastic. Guess each rig, water source, heat source performs differently.

[Prairiepiss]

All the more reason for people to run the crap out of their stills. Playing with every little setting. So they can truly find what works best for them and their still. Not to mention its a lot of fun.

[Usge]

i was considering doing this also. Would building a jacket outside the column make it easier to control?just like a liebig.

This works too. There are designs like this from Mile-hi. As to whether it would make your particular still easier to control or not...compared to any other option...it would depend on too many variables/unknown for me to comment one way or another (ie., where it's placed, how big it is....how much water flow...what temp of the water, etc). It "is" possible to overbuild these things...to the point that even with just a drip coming out of them they knock down "everything" you can throw at it heat wise... and you can't get a range of control over them. You want everything to work together and have a range of adjustment. I agree with PP that controlling heat is usually the easier/more effective way to make adjustments to these stills during a run. But, however it works out best for you is fine.

[biker geek]

Thank you for your responses all.

PP; I have a riser that is 2"x30" going into a 90 then a 45. I would put the top of the coil about 4-5" below the solder joint for the 2" 90. I have an SSR power controller and a 5500W low density element for heat.

I think I will go ahead and add the cooling coils to the riser.

[Prairiepiss]

I would place the coils 2" under the solder joint. That would be plenty of room above it. And give you enough room for one or two more Scrubbers under the coil. That's just my opinion.

Defiantly read the cm mod thread. Link in my signature.

[Usge]

I would take off the 90 and use a 2 x 2 x 2" "Tee". Put the coil in the top part of the Tee (add a bit of 2" pipe if needed), add a cap...bring the I/O from the coil through the cap and solder it. Measure it so the coil hangs down just below the take off. (couple inches). Bring the lyne arm/take off to the right side of the tee at 2" then down 45 and the rest the same. Basically, replacing the 90 over with a Tee to give you a bit of room above the take off to put your coil.