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Odin, I can think of several reasons WHY your rig is performing as well as it does, but everyone isn't going to get those same results... Your column has roughly a 24:1 height:diameter ratio which allows for ample HETP's... The lava (glass) stones of the size you are using, roughly half the volumetric size of a standard marble, retain heat better than scrubbers which most likely helps those HETP's do their job more efficiently... If you have the column packed all the way to the bottom so that the lower tube is less effected by either the reflux or the hot rising vapor that lava packing may be helping to maintain a better temperature gradient than other structured packing types... The rest is all happenstance based on the combined previously mentioned points... The actual %ABV of the wash probably plays a minor part in the scenario as well... But the fact remains that your results are the exception rather than the norm for that particular CM design...

Your results aren't all that unlink what I encounter with my 1.25" LM reflux column... I get higher purity at faster take off rates than one might be inclined to expect... I've always attributed it to luck but there is most likely some design aspect that causes my repeatable results... I'm surprised every time I do a run, whether in reflux or pot still mode, so it's true that some rigs do perform beyond the general consensus as well as theoretical calculations... I've had rigs that performed dismally and am more than pleased that my small scale rig outperforms several of those...

Maybe we just have the "Midas Touch"...

Odin I am curious about your packing, is it porous and light weight, sort of expanded clay type material or more like solid glass? Just out of curiosity did you ever do a side-by-side run to compare it to standard scrubber type packing?

It would be interesting to split a wash and run 1 half through your larva stones and then change the packing and run the second half to see if you have found a significant advantage with the packing.

Nice "classy" reply above Rad!!! True experts who are comfortable with their level of knowledge either ignore questionable statements, seek clarification, or correct them gently. It is so much more positive to offer encouragement than to come up with disparaging remarks.

Odin, I'm getting 95% out of my CM using 1/4" raschig rings in the bottom of the column and copper mesh in the top. Like Myles I'm curious to know more about your packing. There are many variables impacting on speed, quality and abv of our different stills' production/output which limit and/or improve our success.

I have seen brown "stones" in the hydroponics section of some garden centres. Is this what you are using? I think it is available in different sizes - I thought they were ceramic, but I wasn't paying close attention at the time. Their main advantage over raschig rings would be their porosity as well as the external roughness which they have in common with raschig rings and etched SPP (which others are using to great advantage).

Odin,- good to know others are making their CM's "sing". - Keep us posted.

Odin wrote:Putting a cross tube just under the take off point ... I am not sure what this would add to the already in place VM cooling: everything is just sent down the column. Might be difficult to manage. Odin.

Just saw this Odin, thanks for your thoughts. I guess I was intuiting the same thing re management of column.

likkerluvver wrote:Nice "classy" reply above Rad!!! True experts who are comfortable with their level of knowledge either ignore questionable statements, seek clarification, or correct them gently. It is so much more positive to offer encouragement than to come up with disparaging remarks.

Without hands on experimenting with his exact equipment I can't give a better evaluation... And given the fact that I partake in this hobby more for relaxation than to play extensively with theoretical equations I can live with "If it works, it works."... Sometimes I don't even want to know "why"...

A very informative thread and great to see healthy debate, back when Odin was apparently a poorly regarded newb.

Wow you have revived an old thread! I am not going to go back and reread the posts but I will restate my position on this. CM got a bad rap and well deserved with the original designs that we had back in 2010 and earlier. Through the innovative minds on this forum and the new pioneers in the field we have redesigned the CM still with multiple controls and now the stills can reach equalibrium and 100% reflux. This is now in my mind the most flexible reflux still.

It isn't obvious to me even after hours and hours of reading what is outdated or current. I certainly mean no controversy by reviving this, but am struggling to discern the difference between stuff here and on original site.

Coaster wrote:

Kifi wrote:.....6. VMs have their own challenges - like you can blow them up if your heat input overwhelms your cooler during equilibriation and you don't have a safety valve built in. Or implode the column if you forget to open it at the end of the run when you turn the heat off...Kifi

@ Kifi,

All the Vapor Management (VM) stills I have ever seen have a reflux condenser in addition to the VM product condenser. If the reflux condenser in a VM still is manufactured correctly it has an atmospheric vent. The atmospheric vent in the VM reflux condenser will prevent over pressurization of the boiler and/or the column exploding and will also prevent the boiler and/or the column from imploding.

Regards,
Coaster

+1 Coaster

I placed my finger over the 3/8 hole I have in the top of mine this morning just before it started to take off.
To my supersize it built up pressure fairly quickly. Anyone out there looking to build a vm be sure to have at very least a 3/8 vent or else it can and will explode!

mulligan wrote:It isn't obvious to me even after hours and hours of reading what is outdated or current. I certainly mean no controversy by reviving this, but am struggling to discern the difference between stuff here and on original site.

I was looking for an image that would better explain it but many Distiller's were building it back in 08 through 2010. Basically it had no valve controls for the water and for a reflux condenser it only had a pipe going horizontally through at about 3/4 of the way down from the top then bending up and returning through the column at about 6-8" above thus only allowing for passive reflux at best.
The ones you see today have a dephlagmater as it's reflux condensers although there are a few well built coil condensers. I think the main design that I like best on mine is two valves that splits the water intake to the dephlagmater and the shotgun condensers.

I just finished mine and yesterday afternoon ran the vinegar/water through it to clean, haven't even ran the sacrificial wash through it yet.
Points to note,
1) with a deflag on top I can instantly kill output by adding water flow.
2) I'm running separate water lines to the deflag and condenser.
3) Water volume is a lot less that I expected. The washing machine fills the washtub twice when running, I ran the still for a couple hours and never came close to filling it once.
4) I'm currently running a 1" over 1/2" liebig until my shotgun is completed and it had NO trouble knocking everything down. If fact, the liebig was cold 3/4 the way up and water flow was very slow.

I have a separate potstill head for my keg but I might try running the CM column as a potstill just to see. Probably leave the lava rocks in it as well "just to see".

Seemed the simplest to build/operate so I'll let you know if it's true. lol!

Sounds about right goingbroke2, on my CM it takes very little water to run my shotgun condenser as my exit stream is just a little greater than my product collection and the exit water is still cool.