Why does my pot choof ?

by **Linny** » Sat Jan 05, 2013 7:21 pm

i have a keg 2" pot which has a 600mm column and 3/4" take off which reduces down to 1/2"-3/4" leibig condenser which is also 600 long.... on LPG 2 ring burner

im starting to notice that at the higher temps 94-98*C it starts to choof like a train lol. As if it is pressurising ? i played with water flow and not much makes difference , i dont bother touching the burner since its only a 2 ring and doesnt do much.... any idea's ? is the condenser too small ?

No steam comes out , just the sound.... weird

by **MacStill** » Sat Jan 05, 2013 7:27 pm

It's a common thing with a pot usually referred to as "huffing"

There's a few ways to prevent/minimise it that you should find by doing a search, personally I never worried about it and just put up with it ;-)

by **Linny** » Sat Jan 05, 2013 7:33 pm

cheers ,,,, no wonder i couldnt find anything ,,, typed in Huff , and viola!

by **crow** » Sat Jan 05, 2013 7:42 pm

pot and choof just don't look good in the same sentence :laughing-rolling: :laughing-rolling:(was waiting for mullamulla to chime in) :laughing-rolling: whach a few strands of ss scubber in the outlet, problem solvered :handgestures-thumbupleft:

by **Sam.** » Sat Jan 05, 2013 7:43 pm

Chuck some copper mesh up your condenser if its a worry, used to shit the fuck out of me

by **SBB** » Sat Jan 05, 2013 8:24 pm

As Macs already said its pretty common, Ive never had a pot yet that didn't want to huff at least a little toward the end of a run.
As you've already noticed its huffing at the higher temps, in other words when the alcohol content of your wash is starting to get depleted.
From my understanding huffing is caused by the vapors collapsing to fast as they hit the condenser, Those vapors collapse at different rates depending on their makeup which changes as you keep drawing of the ALC from the wash.
A couple of things that can help at times besides packing the condenser are running your condenser a bit warmer and or putting a bit more heat into the boiler.
Ive never personally had much luck with the last of the three methods, but have read that some people have.

by **bt1** » Sun Jan 06, 2013 7:25 am

+1 SBB,

A couple of issues on design may also be in play. From past reading and fair bit of build vigour (read: boredom relief) in the hybrid pot days come up with a few ideas that seem to work.

Add a turbulator tip to the input end of the Leibig...the swirl effect I expect to mix up/stretch out the point at which vapour contacts cooler surface and starts to collapse to liquid... a progression rather than sudden collapse.

These are simple knock in slightly triangulated waste pieces of copper that are flattened out and add a 180 twist. it should knock in tight to inner tube of leibig. On the tail of the tip, I also add a few feet of single strand copper wire in a very loose spiral wound pattern and stretch it down the length of the condenser.

The other consideration is design. From Lyne arm to condenser throat most folk use reducers in a stepped down arrangement. Had better luck with using a tapered cone so no sudden steps. This goes way back to the old school tapered coils idea and reading I pinched. The sudden step down face of a reducer is thought to cause a rebounding type effect...harmonic thing.

I had a tapered cone on a hybrid but it was so dam ugly, (hand made in a hurry cut down 2" pipe) I scrapped it in the end but you have the idea. I think EG & Mac make cones if you want a nice well made one.

Huffing don't effect taste it's just bloody irritating to me ...up to you I guess.

bt1

by **bt1** » Sun Jan 06, 2013 7:46 am

here you go...

Dug the shit out of the scrap bin... I did warn u it was fugly...

Image017.jpg

And Tip to add to leibig

Image018.jpg

posting early build embarrassments
bt1

by **Andy** » Tue Jan 08, 2013 7:34 pm

mine does it about half way through a run (but can only hear it is u get real close) and gets louder. once it gets loud enough to hear a couple of steps away from it thats when i know to turn it off as ABV is about 15%.

by **SBB** » Tue Jan 08, 2013 8:19 pm

Andy wrote:once it gets loud enough to hear a couple of steps away from it thats when i know to turn it off as ABV is about 15%.

Good stuff Andy, thats what running a still is all about , I think, using your senses and learning to use your stills little idiosyncrasies as useful tools is the way to go. Its been done by sound, feel, taste and smell for hundreds of years now :handgestures-thumbupleft: :handgestures-thumbupleft: :handgestures-thumbupleft: All the fancy gadgets and calculations in the world wont make a better product.