Fix a "huffing" condenser

[CoOkEd]

I finally finished off the fabrication on my still. It's just a tiny one to start out with and get used to how things work and the correct fabrication techniques. 8 quart SS stock pot, 3/4 x 10" copper column out the top. 90 degree bend to 1/2" reducer. 12" horizonal run to another 90 bend and 3/8" reducer. 28" liebig condenser, 3/8 inner, 1/2 outer. I use a 5 gallon bucket and gravity to run the water throught the liebig. I have to run the water in the top and out the bottom right now because gravity isn't enough to run the water fast enough from bottom to top. Powered by a coleman propane camp stove.

I ran some water, then some water and vinegar x2 to check out for leaks. A little flour paste on the non soldered joints and around the pot lid and no more leaks. Ran a couple of bottles of cheap wine that nobody wanted to drink through as the the cleaning run. Everything seemed to work fine. I could crank up the power on the stove and the liebig seemed to knock down everything just fine. The distillate came out cool. I'd post the pics but after viewing everyone else's, I'm not too proud of my soldering and it's a little small. Far too embarrassing to do that. Will just hide in my garage with it instead...

On my first real run, I loaded up the stock post with a gallon of rum wash. Eveything went fine, and ended up with about 690 ml of output. next step figure out how to make the cuts better. I kept about 300 ml from the middle and it tastes suprisely good. need to work on figuring out the cuts now. Have a few more batches on the go.

However, to the point of my post. Even though my condenser appeared to be knocking down all of the vapour, it was making a "huffing" sound and if I looked carefully, I could occationally notice small little vapour clouds. If I placed my mouth next to the output, I could feel to the puffing on my lips as well. It was quite cold outside and I could see my breath when I breathed.

Was that alcohol vapour being pushed out from the liebig not being able to handle all the vapour? Or was I noticing air moving in and out caused by the contraction of the vapour condensing at the top of the liebig?

Mod edit: Original Post: http://homedistiller.org/forum/viewtopi ... 15&t=13092

[LWTCS]

It's not uncommon for Liebigs to huff a bit.

There are some pics of turbulators around here some where. These turbulators are kind of like a twisted copper ribbon (or the like) inserted just before your condenser. Turbulators can help reduce the huffing.

Seems like a 3/8 is very small.I recon a 1/2 would really help minimize your huffing too.

[blanikdog]

I'd do something about reversing the coolant flow through your condenser. It really is better to have the coldest point at the condenser exit.

blanik

[HookLine]

Yup, 3/8" a little small. 1/2" would be better.

[CoOkEd]

I was on a budget when I built the leibig and the 3/8 & 1/2 where all I had in the garage. I will upgrade to 3/4 & 1/2 soon.

I will try the turbulator before the condenser. A full twist will do the trick?

When I get a pump working I will certainly reverse the direction. I just couldn't get any flow happening the other way as there was too much water in the liebig and the hoses to be pushed out by gravity alone. It would flow, but only a trickle.

Could it have been vapor coming out of the bottom? I don't want to risk an explosion. I had several fans running during my session to move the air around just in case.

[Dnderhead]

bring a return line back into the tank, then the pump just cercelates once the lines are full.

[Hawke]

The huffing comes from the vapor collapsing, then fresh vapor rushing in. The turbulator at the top will help. Also, just a small piece of a scrubber tucked into the output end helps a whole lot.

[Husker]

Like others have said, huffing is due to too rapid vapor collapse. Since you are running the water backwards, that is what is causing this to happen. The pure hot vapors are hitting the coldest water and instantly collapsing, creating a vacuum. If you reverse that, then the water will be heated, by the time it works its way up (run the water only fast enough to knock down all the vapors). That way, the vapor will gradually collapse the first half or so of the condenser, and not in the first inch. It will create a LOT less huffing. Then any of the other 'hints' will also help (a vapor spinner/turbulator, some copper packing loosely fitted in the end of the condenser, etc).

H.

[Usge]

yup....having cold water at top just makes it worse. Just putting a little scrubber in the end of the output tube helps some. But, if you want to knock it all the way down, you need to get some copper mesh rolled loosely and push about 6-10 inches up the output tube....carefully...so as not to pack it in there. You want to fill up the space, but don't want to get it too tight, or pack it in. Blow through it to make sure it's still nice and open. That will stop your huffing and also make it "stream" instead of spitting/dribbling. You can get the copper mesh at brewhaus.com for cheap. And you'll have plenty to spare (it comes in a folded sheet). It's very easy to cut with just scissors.

[Nightforce]

I can't comment on much, but from recent experience mine was huffing a little. A after putting a turbulator in it (~9" long) it seemed to really help knock down the vapor and reduce the huffing significantly. You can still hear it faintly when really close to the output but 3' away it's virtually silent. I would say that with reversing the flow and adding a bit of scrubber you'd all but eliminate the huffing on your 3/8" × 1/2" condenser.

[Sulaiman]

To eliminate 'huffing' add (porous) boiling stones to the pot to prevent superheating and 'bumping'.

[still_stirrin]

To eliminate 'huffing' add (porous) boiling stones to the pot to prevent superheating and 'bumping'.

Thanks for the update on a 10 year old thread.

Huffing is usually the result of ice water in the coolant reservoir causing vapor collapse in the product condenser. It is typically solved by slower water flow which allows a temperature gradient in the product condenser.

Boiling chips just add a nucleation point in the wash for the molecules to coalesce and bubble to the surface. Typically, it simply speeds the vapor flow and reduces the likelihood of "bumping" as you've noted.
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