new still "huffing"

[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?

[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.

[CuWhistle]

While this original thread is a bit old (found in the Reading Lounge) I have a related question.

My liebig condenser does huff a little bit from time to time, even though I have the water flow in the right direction. I looked it up and read this post but I have not worried too much about it since it isn't severe and doesn't usually last for very long before balancing out. It is usually a fairly fast little puffing sound with some visible vapour discharge.

Yesterday I did a spirit run with a charge of 20 litres at 40% ABV. The distillate started to come over at 80% and a steady rate, I turned the heat down as much as possible to slow it down for quality and the first couple of jars came over fine. Luckily I was actually watching it at the time and I noticed the drip from the condenser stop. I thought the flame had gone out from being turned down too low and the breeze coming through the open door, so I was having a look when the condenser spurted juice everywhere. It had obviously vapour locked for some reason and then let go once boiler pressure was high enough. This happened repeatedly for quite a while with the output going from normal (fast drip / slow run) to nearly stopped, then a big spurt, then back to normal and so on.

At first the spurts were some time apart and quite severe. They became smaller but more frequent until it eventually stopped and the run continued on as normal.

Anybody seen this before??? What causes it???

I was thinking the AC of the charge may have been too high at right on 40% especially with the initial output being 80% from a pot still.

[HolyBear]

Vapor lock... keep the vapors easing through with heat...

Its kinda like eating beans on Saturday night, the next morning when the heats turned off, that gas has got ta go somewhere...

[CuWhistle]

This is the only time it has done it so far. Stripping runs are not a problem and this was the first time I have done a good sized Spirit Run through this rig.

I'll have to wait and see if it repeats the symptom at a later date.

So Wacabi1, what you are saying is keep the heat up. I had it down low to try for a slower Spirit run, which is what I thought is the correct thing to do.
If that is not the case I have a 2 speed pot still. ON or OFF.