Liebig condenser on pot still too small/ineffecient?

[The Booze Pipe]

I run a liebig condenser on my 13 gal kettle with propane. its a .5" vapor tube inside .75" water jacket 30.5" total length; with constant water flow (no recirculating). When stripping hot & fast I can see a slight vapor rising from the output. distillate collects at around 95f(35c). Is my condenser not big enough to knock down all the ethonal vapors?
I am in the middle of my first spirit run, low & slow, and I don't see any vapors rising from the distillate; ouput temp is 79f (26c).
Thanks for any input.

[Grappa-Gringo]

I was looking for a similar thread with a similar question:
I run an 1.5 inch leibig with a 1/2 inch on the inside. I get lots of output, but at times, usually at the beginning of the run it'll come out hot or with a
steam vapour... which I know isn't good. At that point I turn down the heat (propane) and let it run.
My drip is usually 25-30 minutes after I light it up.
So my question is... is my leibig not cooling it enough? I'm running it straight from the tap, without recycling it..It's just over 24 inches.
Honestly, I don't have an issue with it... Just wondering

Comments would be great.
gg

[S-Cackalacky]

There's a calculator on the "Parent site" that can tell you approximately how much power it can handle. Some options might be to cut back on the power, or try stuffing some copper mesh up the business end, or take it apart and make some enhancements to it. Enhancements - tack solder a piece of 6 gauge solid copper wire in a spiral around the outside of the vapor tube and a flattened piece of the same on the inside of the vapor tube. This will greatly enhance the efficiency and allow you to run it harder. Another option would be to crimp the inner vapor tube with pliers every couple of inches with every other crimp at 90 degrees to the previous one. Either of those techniques will cause turbulence in the water jacket and in the vapor path which gives better cooling and more vapor exposure.

[The Booze Pipe]

How would one determine the heat output with a propane burner with an adjustable regulator?

[Halfbaked]

Have you put any looooooosly placed copper scrubbee in it? Something else to think about is your propane burner might be heating liebig. If you don't have a heat shield around your keg maybe that might help. Funnel the heat away from your condencer. Or maybe extend it away from the keg a little. I had/have a liebig that is 30 inches also.

[The Booze Pipe]

Good point with a heat shield. Do you have a picture for an example? Where would the copper scrubber be placed? I'm thinking the next stripping run I do I'll run less heat.

[Snackson]

Another option would be to crimp the inner vapor tube with pliers every couple of inches with every other crimp at 90 degrees to the previous one.

Would you really want to crimp the vapor tube on your condenser? I understand the theory behind it but wouldn't that cause a choke point if it happened to puke?

On another note I have rad a few times on here that the vapor you see at the beginning is CO2 working out of the mash/wash. Then again, if it was a spirit run with feints you wouldn't have CO2 in it.

[Yummyrum]

Crimping is just causing the inside of the vapour tube to be deformed by no more than about 1mm .
Regular crimps along the length just give the vapour some turbulance but I seriously dont think it would cause a major issue with puke jambing..
I have crimped all the liebigs I have made .Admittedly I dont do grains but I would think that if a blokage was to occur then it was just as likely to hav occured without the crimps

[skow69]

I run a liebig crimped as S-Cack described. It works fine. It only needs to carry as much as what comes out, so a pencil lead size stream of liquid. For vapor, a restriction just increases the speed at that location. Think of going through rapids on a river. The crimps prevent laminar flow of the water also. If I make another one, I will crimp it tighter.

[skow69]

Crimping is just causing the inside of the vapour tube to be deformed by no more than about 1mm .
Regular crimps along the length just give the vapour some turbulance but I seriously dont think it would cause a major issue with puke jambing..
I have crimped all the liebigs I have made .Admittedly I dont do grains but I would think that if a blokage was to occur then it was just as likely to hav occured without the crimps

My crimps reduced the inside of the vapor tube from 1/2 inch [12mm] to 1/8 inch [3mm]. They were made with a C-clamp, counting the turns for consistency. I think it can dramatically reduce the required size of the condenser. Mine is 18" long, hangs vertically, and easily handles my 2625 max watts of internal elements.

I only run low wines through that still. I wouldn't suggest it for anything that could puke solids.

[S-Cackalacky]

About crimping - I used Vice Grip pliers so that I could control the depth of the crimp. Doesn't really need to be too severe. My liebig is 24" (water jacket). But then, I don't push it too hard. I only run 1375W max. That said, I think my next condenser will be air cooled.

[cranky]

I have a spiral of wire inside mine, works real well. I had plans for some scrubbie but just never added it. Crimps are something you have to think of before building the scrubbies or wire can fix a problem after assembly. I also have a 24 inch extension I can add if I want to but since I run 36 inches I have never had to use the extension.

[Halfbaked]

http://homedistiller.org/forum/viewtopi ... 33&t=17058 heat shield thread

[still_stirrin]

I run a liebig condenser on my 13 gal kettle with propane. its a .5" vapor tube inside .75" water jacket 30.5" total length; with constant water flow (no recirculating). When stripping hot & fast I can see a slight vapor rising from the output. distillate collects at around 95f(35c). Is my condenser not big enough to knock down all the ethonal vapors?...

What you're seeing is the result of a fast vapor velocity. The vapor coming off your riser is moving quickly and carries a lot of heat. Into the Liebig, you reduce down to 1/2" and that speeds the velocity even more. So much so that it doesn't all get condensed...most does, but not all.

As some have suggested, adding a little (loose) ball of scrubbie will help slow the vapor long enough to contact and condense on the Liebig vapor tube walls.

Another method suggested is to increase the contact surface area inside the tube...that is, add the twisted and flattened (or crimped) copper tubing. It creates more conducting surface area for the vapor to give up its heat to.

...I am in the middle of my first spirit run, low & slow, and I don't see any vapors rising from the distillate; ouput temp is 79f (26c)...

Because the vapor velocity is slower (lower mass output from the boiler). Therfore, there is adequate contact time bewteen the vapors and the walls of the vapor tube.

Your Liebig is long enough for your heat input, but the flow velocity is making it innefficient when stripping. A larger diameter tube would help too because the velocity would be slower. But you've got what you've got. So, you must modify it to improve its performance.
ss

[frunobulax]

Aside from what everyone said about creating turbulence with a wire etc..Propane is very hot and some of the burners put out an obscene amount of heat. Maybe you're pushing a little too hard and not using enough water?

[S-Cackalacky]

Aside from what everyone said about creating turbulence with a wire etc..Propane is very hot and some of the burners put out an obscene amount of heat. Maybe you're pushing a little too hard and not using enough water?

+1. Doing a stripping run doesn't mean cranking it up as high as it will go and sayin' a prayer in hopes that your liebig is big enough to handle it. You just need to run it with a little common sense and if you feel that it's falling short of expectations, fix it, or build a shotgun.

[jedneck]

If you think its to small, you could always build a second add on leibig for stopping runs. It would also move your collection point farther away from the heat.

[thecroweater]

Mine wasn't crimped, I could strip 50 litres in 45.minutes and barely have the water moving thought it. The jacket was about. 5 ft, every problem I've ever heard of is from the Liebig being to short

[shadylane]

Plan B
If your condenser is too small and inefficient.
A small pre-condenser could be added for preheating the next batch.

[still_stirrin]

Genius Shady.

Waste heat reclaimation. I like it. Also reduces heat build up in a reservoir (recycle) cooling system, if you use one.
ss

[Hound Dog]

If you think its to small, you could always build a second add on leibig for stopping runs. It would also move your collection point farther away from the heat.

This is a better plan than turning down the heat!

[engunear]

Adding second cooler to chill the distillate is a good. Having a hot flammable liquid in the room with me gives me the heebie-jeebies. I've tried fine bore (3/16) and wide bore (1/2 in) and like them both and they work about the same.

The second cooler can have a much smaller bore than the first, so there is more contact between distillate and coolant, and its not as heavy. Copper brake pipe (3/16 inch) works well. If you do that, make sure there is a large vent at the join, so if a bit of junk comes over and clogs the 3/16 pipe you don't have a sealed system.

BTW, I'm 99% sure the web calculator suggests building stills that are too long. The reason is that the heat transfer coefficient they suggest (850W/sq m) is for glass not copper. Using 3000W/sq m gives designs that more closely match practice.

If you are worried about your flow rate and vapour coming out, stick a thermocouple up the back end of your system. You can detect the boundary between vapour and distillate by a cliff in the temperature, with a fluctuating transition. If its too close the the distillate outlet, crank up the coolant flow. Since water pressure (and thus flow) can vary through the day, having a safety margin is a good idea.

[The Booze Pipe]

I run a liebig condenser on my 13 gal kettle with propane. its a .5" vapor tube inside .75" water jacket 30.5" total length; with constant water flow (no recirculating). When stripping hot & fast I can see a slight vapor rising from the output. distillate collects at around 95f(35c). Is my condenser not big enough to knock down all the ethonal vapors?...

What you're seeing is the result of a fast vapor velocity. The vapor coming off your riser is moving quickly and carries a lot of heat. Into the Liebig, you reduce down to 1/2" and that speeds the velocity even more. So much so that it doesn't all get condensed...most does, but not all.

As some have suggested, adding a little (loose) ball of scrubbie will help slow the vapor long enough to contact and condense on the Liebig vapor tube walls.

Another method suggested is to increase the contact surface area inside the tube...that is, add the twisted and flattened (or crimped) copper tubing. It creates more conducting surface area for the vapor to give up its heat to.

...I am in the middle of my first spirit run, low & slow, and I don't see any vapors rising from the distillate; ouput temp is 79f (26c)...

Because the vapor velocity is slower (lower mass output from the boiler). Therfore, there is adequate contact time bewteen the vapors and the walls of the vapor tube.

Your Liebig is long enough for your heat input, but the flow velocity is making it innefficient when stripping. A larger diameter tube would help too because the velocity would be slower. But you've got what you've got. So, you must modify it to improve its performance.
ss

This makes the most sense to me. I will try some way of slowing the vapor.

[engunear]

An alternate explanation of this is that what you are seeing is the boiler pot venting air at the beginning. It starts full of air and it has to go somewhere. It carries droplets with it so you can see it. You know the output of your condenser is cool (26-35C condensate). This does not happen in the middle of the run, when the air has vented.

So you could just ... not worry about it.

My understanding is a little different to some others; when pure vapour hits a cold surface (colder than the boiling point) it condenses. This creates a vacuum which pulls more vapour into the space. This continues until the surface heats to the boiling point - limited by ability of the condenser to carry heat away (thermal resistance). This is why a thumper thumps at the start - it sucks liquid from the thumper back up the steam pipe because it has vapour touching cooler liquid. This is violent. If it wafts around past something that is cold it has air in it. (Don't worry, I'm wearing my asbestos underpants and expecting some disagreement here.)

You can measure your heat input ... assuming that you are condensing everything : measure your inlet water temperature and your outlet water temperature. Say you get 20C and 60C leading to a difference of 40C. Measure your flow rate by seeing how long it takes to fill a known volume - say a 750ml wine bottle. Say it is 30 seconds.

The flow in litres per sec is 0.750/30 = 0.025 liters / sec.

The power is the temperature difference x flow x specific heat water = 40 x 0.025 x 4180 = 4.2kW.

(PS. My apologies to those whose emails have been spammed by me editing this post too many times.)