Weird sound coming from outlet pipe

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nsgibson
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Weird sound coming from outlet pipe

Post by nsgibson »

Hi everyone,
I have just finished construction of a copper potstill, 5 gal (actually 4.5), column 18"L, 1.5" ID, Liebig condenser which is 1/2 tube inside 3/4" tube 16" long. Electric with 1500W element. I based my design off the Clawhammer 5 gal design, looks identical. I did the cleaning run and ran my first strip run on a batch of UJSSM. Good results, no leaks, at full power I can get a good stream coming out of the outlet pipe. I am new to this but it seems like all is well. However, I am getting a sound coming from the outlet pipe that in all my reading have not came across and didn't expect. It's best described as air huffing, about 7hz or 7 "puffs" per second. This is with pretty good distillate output. I have only run twice but seems to appear midway through the run and stays. If I cover (briefly) the output pipe with my finger it goes away so I know that's the source. So I have a few questions:
1) is this normal or abnormal
2) if abnormal, is it due to a mis-sizing of one of the components like the column or the condenser? I thought I would avoid this by shamelessly emulating a design being sold.
3) is there a safety issue? E.g. Could there be excess vapor? Like I said I am gettting very good condensing and output.
4) would any additional info help?

Appreciate any feedback!! You guys have made possible all of my progress so far. So excited about contributing in the future.
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Re: Weird sound coming from outlet pipe

Post by greggn »

"Huffing" (you got that term right) is caused by vapor collapsing violently in the presence of excessively cold coolant water. Try dialing back your flow and make sure the coolant enters at the bottom of the liebig.
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Re: Weird sound coming from outlet pipe

Post by still_stirrin »

Yep. greggn nailed it.

Huffing, from vapor collapse, is because your cooling water is too cold at the top of your product condenser, often called, “shock cooling”. Slow the coolant flow until it is warm to the touch at the water’s outlet.

And then, if you get puffing at the product outlet, lower your heat slightly. At 16”, your Liebig is just on the edge of being long enough. Don’t overcompensate by speeding up the water flow. Rather, reduce the heat slightly.
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Re: Weird sound coming from outlet pipe

Post by Expat »

Make sure your coolent input is at the take off end of the condenser.
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nsgibson
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Re: Weird sound coming from outlet pipe

Post by nsgibson »

Well I am glad to figure out what this is! So I do already have my inlet to the condenser at the bottom. I am using water out of outdoor faucet so it's cold to the touch, using a landscape pond pump at the bottom of a bucket and I change the water when it gets warm, about every pint or so.
I think the easiest thing will be to dial down the condenser flow. I will do that on the next run. Hopefully that will do the trick but if not I can look into a continuous flow system sized to have a warmer stable water temp.

Thanks!
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Re: Weird sound coming from outlet pipe

Post by Swedish Pride »

a wee bit of a scrubbie up the business end of the condenser did the trick for me
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Re: Weird sound coming from outlet pipe

Post by zapata »

And I've never thought huffing was actually a problem anyway.

But why not just runoff the hose itself? Absolutely no need for the too small reservoir or pump. Just go hose, straight onto the condenser. Reduce flow so it comes out warm and it probably won't huff.
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Re: Weird sound coming from outlet pipe

Post by johnsparrow »

Swedish Pride wrote:a wee bit of a scrubbie up the business end of the condenser did the trick for me
That would be a very easy sentence to take out of context.......
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Re: Weird sound coming from outlet pipe

Post by johnsparrow »

zapata wrote:And I've never thought huffing was actually a problem anyway.

But why not just runoff the hose itself? Absolutely no need for the too small reservoir or pump. Just go hose, straight onto the condenser. Reduce flow so it comes out warm and it probably won't huff.
Shock cooling, from what I have read, is a bad thing for your spirit, although, I have not yet gone through the 412 million hits on the search page to find out exactly why this is. At this stage all I can find is people repeating that it is a bad thing.
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Re: Weird sound coming from outlet pipe

Post by Skipper1953 »

I believe zapata has the best solution to your "problem".

I have never really understood why huffing is perceived as a problem, either. I can see where it might be a bit annoying but I think harmful is a stretch.
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Re: Weird sound coming from outlet pipe

Post by Truckinbutch »

Huffing will enhance smearing . Not desirable . Operating a still is not a 'turnkey' operation . you need to achieve a balance throughout the run . This is done by regulating heat input and coolant flow .
A temperature gradient ( Cold at product output and hot at input ) is desired . That is achieved with regulation that changes throughout the run . Accelerator (heat) and brake( coolant flow rate) .
Your condenser is marginal in length . A longer one would make your rig easier to drive .
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Re: Weird sound coming from outlet pipe

Post by jon1163 »

Truckinbutch wrote:Huffing will enhance smearing . Not desirable . Operating a still is not a 'turnkey' operation . you need to achieve a balance throughout the run . This is done by regulating heat input and coolant flow .
A temperature gradient ( Cold at product output and hot at input ) is desired . That is achieved with regulation that changes throughout the run . Accelerator (heat) and brake( coolant flow rate) .
Your condenser is marginal in length . A longer one would make your rig easier to drive .
How does huffing enhance smearing? I would think that once the fractioned vapor is in the lyne arm it is what it is. Can you explain to this public school kid how rapid condensation would smear more? thanks truckin. I always enjoy getting schooled
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Re: Weird sound coming from outlet pipe

Post by still_stirrin »

jon1163 wrote:How does huffing enhance smearing?...Can you explain to this public school kid how rapid condensation would smear more?...I always enjoy getting schooled.
Well, here’s a lesson for you. Study hard...the test is tuff. viewtopic.php?f=16&t=25511&p=6944244#p6944244
And another read: viewtopic.php?f=15&t=24142#p6929053

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Re: Weird sound coming from outlet pipe

Post by HDNB »

vacuum pulling the air in also pulls on the vapour, the huffing happens on the other side too. Arguably that could add to smearing....
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Re: Weird sound coming from outlet pipe

Post by shadylane »

jon1163 wrote:How does huffing enhance smearing?
That's the nature of a small pot still, it always smears and usually huff's
Just maybe :?: it smears less while it's huffing :lol:
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Re: Weird sound coming from outlet pipe

Post by jon1163 »

still_stirrin wrote:
jon1163 wrote:How does huffing enhance smearing?...Can you explain to this public school kid how rapid condensation would smear more?...I always enjoy getting schooled.
Well, here’s a lesson for you. Study hard...the test is tuff. viewtopic.php?f=16&t=25511&p=6944244#p6944244
And another read: viewtopic.php?f=15&t=24142#p6929053

ss
In the military we did what was called teach the teacher. here is what I've learned over the past several hours:

Shock cooling is real and you don't want it. Lots of people put a valve on the inlets of their condenser coil and also jacketed coil. Usually the inlet to the condenser is sufficient to use a ball valve but on a jacketed condenser a needle valve may be more appropriate. This is because your a reflux with a jacketed condenser requires more fine-tuning and a ball valve is much harder to regulate slow than a needle valve.

You want a gradient of temperature from the inlet side of your condenser, cold, to the outlet of your condenser, warm. This prevents shock cooling. Shock cooling is bad for several reasons. 1 it can produce off flavors in your alcohol. It does this by creating a low pressure environment where the liquid that is condensing sucks moisture from the surrounding air when being condensed quickly. This moisture from the surrounding air binds to the condensate and may produce off flavors.

Further, shock cooling can actually lower your ABV! It does this on both the inlet and Outlet side of your condensers. on the outlet side the low pressure caused by rapid condensation will suck the moisture and air from the outlet side of the condenser. any moisture will bind with your condensate producing a lower ABV. On the inlet side of your condenser rapid cooling can also create a low pressure environment, sucking moisture from your boiler or thumper that would otherwise not make it to the product condenser due two parasitic condensation.

:)
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Re: Weird sound coming from outlet pipe

Post by zapata »

Shock cooling and huffing have absolutely zero effect on my product, with my pot still, the way I run it. I have done many replicates with huffing and without.

I don't do the replicates on purpose though. Here's the deal, due to design I (almost) always run my reflux rig off a reservoir and pump. Again, due to design, my reflux cooling rig requires no throttling of water, so there is no valve. Just a pump and a loop of tubing. Works great.

I prefer to run my pot and liebig straight off the tap without the reservoir. When I do so, I regulate the water to conserve it. It comes out warm, there is no huffing.

However, if I have recently done a reflux run, the reservoir is sitting there full of water ready to go, so I use it to cool my liebig. No valve to throttle it means it huffs, especially in the beginning when the water is cold. Really especially in the winter when the water is really cold. Now eventually the reservoir gets funky so I empty it, or I want the reservoir to brew up a giant batch of compost tea or something. So once the reservoir is empty, I don't use it again until I need to reflux something.

I pot still more than I reflux, and very roughly half my pot runs end up on the reservoir with at least some huffing. Slightly less than half of those runs are in the winter with much more huffing (I don't reflux as often in the winter so I'm less likely to have the reservoir setup when I pot still).

It doesn't make one damn lick of difference to me. If it did, with 20 seconds of work I could have popped a valve in line and stopped it, duh. Or just "wasted" the $.01 worth of water in the res and run off the tap with no huffing.

Now, admittedly maybe this is just me and maybe it's different for others. On a stripping run concern over smearing seems silly. On a 12.5 gallon low wines pot still spirit run, I also think its silly. Maybe my huffing isnt as bad as it could be and worse huffing is worse? Maybe on a smaller scale it matters? Maybe it's my still? It's a fairly normal, 2" riser to 3/4" over 1/2" liebig, but I run a taller riser than most, usually I run with 3 feet of riser. Sometimes 4 feet, sometimes I strip with just 1 foot.

Now, issues besides smearing... moisture from the air causing off flavors? Gimme a break, I'm about to air my jars for 48 hours before cutting and I'm supposed to worry about them being exposed to air for a few extra inches inside the tip of the liebig? Again, maybe this makes a difference in some people's setups, but it doesn't in mine. I'll also mention that I live in the humid south. Not a quite a tropical cloud forrest, but fucking humid (80% today). I almost never have condensation on the outside of my liebig. If it ain't condensing on the outside, it probably isn't on the inside either (though granted there will be slightly different pressure inside a huffing liebig so I can't be 100% certain it doesn't condense atmospheric humidity). Again, maybe this is just me, but if I ran my reservoir today, it would huff, but the reservoir is 75*, my dew point is 73*. I don't know how to correct for whatever pressure difference the huffing causes. Even IF it condensed atmospheric humidity, how is distilled water going to cause off flavors?

Lower abv? Whatever. I don't drink anything at still strength, and if high abv mattered I wouldn't be using the sometimes huffs pot still anyway. Granted I haven't specifically looked for this, but I honestly think I would have noticed. It's true that sometimes I still like an artist and just take one or two measurements and rely on my senses and intuition, but just as often I'm in full science mode measuring and recording everything. I can easily end up with 10+ pages in the notebook for a single run. If my abv was noticeably lower on half my runs I would have noticed. Again, we can look at my conditions today. Reservoir 75*, dew point 73*, and that reservoir will only get further from the dew point. I seriously doubt I'm going to be pulling water out of the air. And this can only happen in the outlet side. On the boiler side it either condenses the mixture of boiler vapors or it doesnt, it can't preferentially pull water out of the boiler. At most it can act like a mini boil ball or tiny dephlegmator, neither of which preferentially condenses water. In fact, if anything it would promote passive reflux and SLIGHTLY raise the abv as that reflux revaporizes before it hits the boiler surface.

All that to say MAYBE it matters for some people. But with plenty of replicates and detailed observations it absolutely does not matter to me. Huffing is an ibservable phenomenon that doesn't really require definition, its obvious when it happens. But if we can define shock cooling as some kind of overcooling that causes problems, then huffing is not necessarily shock cooling as huffing can be harmless. Maybe someone with a small still, ice cold tap water, ridiculously high flow rate, a low dew point, and noxious condensable off flavors floating around in their air might be able to use huffing as an indicator of shock cooling. I don't know as I don't have those conditions.
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Re: Weird sound coming from outlet pipe

Post by johnsparrow »

jon1163 wrote:
still_stirrin wrote:
jon1163 wrote:How does huffing enhance smearing?...Can you explain to this public school kid how rapid condensation would smear more?...I always enjoy getting schooled.
Well, here’s a lesson for you. Study hard...the test is tuff. viewtopic.php?f=16&t=25511&p=6944244#p6944244
And another read: viewtopic.php?f=15&t=24142#p6929053

ss
In the military we did what was called teach the teacher. here is what I've learned over the past several hours:

Shock cooling is real and you don't want it. Lots of people put a valve on the inlets of their condenser coil and also jacketed coil. Usually the inlet to the condenser is sufficient to use a ball valve but on a jacketed condenser a needle valve may be more appropriate. This is because your a reflux with a jacketed condenser requires more fine-tuning and a ball valve is much harder to regulate slow than a needle valve.

You want a gradient of temperature from the inlet side of your condenser, cold, to the outlet of your condenser, warm. This prevents shock cooling. Shock cooling is bad for several reasons. 1 it can produce off flavors in your alcohol. It does this by creating a low pressure environment where the liquid that is condensing sucks moisture from the surrounding air when being condensed quickly. This moisture from the surrounding air binds to the condensate and may produce off flavors.

Further, shock cooling can actually lower your ABV! It does this on both the inlet and Outlet side of your condensers. on the outlet side the low pressure caused by rapid condensation will suck the moisture and air from the outlet side of the condenser. any moisture will bind with your condensate producing a lower ABV. On the inlet side of your condenser rapid cooling can also create a low pressure environment, sucking moisture from your boiler or thumper that would otherwise not make it to the product condenser due two parasitic condensation.

:)
Does this then mean that you can add off flavours to your alcohol when you dilute it ie: moisture binding to condensate ?
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Re: Weird sound coming from outlet pipe

Post by zapata »

No man, all alcohol is a solution of alcohol and water, and can be as tasteless as either on their own. Clean tasting water adds no flavor to alcohol.
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Re: Weird sound coming from outlet pipe

Post by HDNB »

arguably (again) why not? if you dilute with water from Beaver Utah (voted best water in USA) maybe it tastes better...if you get you dilution water from a different Beaver...maybe it tastes worse. (or better? saltier for sure.)
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Re: Weird sound coming from outlet pipe

Post by johnsparrow »

zapata wrote:No man, all alcohol is a solution of alcohol and water, and can be as tasteless as either on their own. Clean tasting water adds no flavor to alcohol.
Then why does the water added by huffing contribute to off flavours?
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Re: Weird sound coming from outlet pipe

Post by jon1163 »

johnsparrow wrote:
zapata wrote:No man, all alcohol is a solution of alcohol and water, and can be as tasteless as either on their own. Clean tasting water adds no flavor to alcohol.
Then why does the water added by huffing contribute to off flavours?
John,
I didn't know rad personally but from what I read he's extremely knowledgeable. What I'm guessing you're getting hung up on here is that, at least in my opinion, this is an argument between theoretical and practical. I imagine theoretically yes you could suck moisture from the boiler and the atmosphere which binds to your distillate to produce off flavors.

Like zapata said though I personally believe that that is probably not really practical to contribute off flavors. You'd have to have some dirty air or smoke in the air or something like that. I would bet it is more believable that huffing might reduce your ABV just a tiny bit.

I was mainly following sbbs advice and reading up on the old posts and trying to learn a bit more. I run a pot and Thumper and it helps quite a bit sometimes but I've never experienced anything "off" from it. I think you would be much more beneficial to concentrate on things like making good cuts and not using turbos to maintain good flavor.

Mind you I'm no scientist and I'm pretty new to this Hobby compared to others around here so take my opinion with a grain of salt.
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Re: Weird sound coming from outlet pipe

Post by der wo »

I think huffing has two side effects:

1. it lowers the output rate. This means it wastes energy. The constantly breathing in of cold air and out warm air consumes energy. Or does this cause reflux? I think only partially, very inefficent way to make reflux.

2. because the vapor flows not directly from the wash surface to the point where it gets condensed, but gets pushed back and forth, this chaotic movement, the permanently changing pressure and the all in all higher vapor speed increases entrainment.
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