VM, CM, and LM confusion

[Saltbush Bill]

it looks like I'm quoting the book, otherwise tell me why I would have mentioned it ???

Because you may have also had personal experience of badly made "small, temperamental needle valves that can be difficult to procure and which often
change their settings with temperature." This doesn't seem to be the case.
That description of needle valves is BS in my opinion.
Sometimes it pays to have personal experience of such things before commenting on them.......it also pays not to believe everything that you read in a book without checking the facts yourself beforehand.. That book has been proven more than once to contain incorrect information.
To say that a LM reflux is not as capable of making great neutral as a VM reflux is , is just plain out wrong.......they are both great designs that do an excellent job of refluxing spirit.
If one is better that the other it is only in the mind of the builder / owner.
Again, if people are having trouble with needle valves its because they are buying cheap arse shit......you get what you pay for.
As for the temperature thing, https://www.theprocesspiping.com/introd ... dle-valve/ Fluid Temperature
Quote
"Needle valves are suitable for high or low temperature applications. For extreme temperatures one need to specify the valve housing and packing/sealing material appropriately to ensure the needle valve can withstand the requirements. The two most common sealing materials are PTFE (Teflon) for a temperature range of -65°F to 450°F (-54° C to 232°C) and PEEK (Polyether Ether Ketone) for increased temperature"
PTFE is approved as a safe material by the forum rules, I cant see to many of us wanting to run our product output at 450F or more.

[Dancing4dan]

download/file.php?id=65781&mode=view

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This would possibly function as a VM still just by reconfiguring.

Reassembled from top down. Starting at the top with that RC (Reflux Condenser) then the sight glass (not needed) followed by the take off valve section. Ensure your top plate with the thermometer has a vent hole. Pack the riser with copper. Route coolant through the Liebig then to the RC

I hope others with more experience comment but I think that would make a VM still. Reflux ratio will be pretty small depending on the size of the take off valve.

If this still is not vented it is potentially dangerous with the valve before the PC. Inadvertently shutting off the valve would lead to pressure buildup if it isn’t vented.

[still_stirrin]

… The part I'm talking about is the part in red … I was thinking about adding a little bit of copper packing in there to help slow the vapor down a bit...

This may seem counter-intuitive, but putting a copper scrubby into the RC (deflagmator) won’t slow the vapor down. It will accelerate it because vapor is a gas and vapors expand, unlike liquids. So, partially blocking the passageway for a vapor in a closed channel (pipe, condenser, etc.) will cause it to speed up.

But, the packing inside the RC will provide more surface area in contact with the vapor molecules and it is also contacting the condenser’s water jacket, and that will increase the heat transfer from the vapor to the condenser thereby greatly improving condensation. The condensate will form droplets on the packing and then drip back down the column (also packed, I’d assume) where the condensate will reboil with heat transferred from the rising hot vapors.

This cyclical “condensing and reboiling” process is called, “reflux” and it allows the components with a higher volatility to be separated from the constituents with a lower volatility.

Restating, the packing in the RC does not slow the vapors down, it helps remove heat by contact (conductive heat transfer).
ss

[Garouda]

I hope others with more experience comment, but I think that would make a VM still. Reflux ratio will be pretty small depending on the size of the take off valve.
If this still is not vented it is potentially dangerous with the valve before the PC. Inadvertently shutting off the valve would lead to pressure build-up if it isn’t vented.

Your solution would also be fine. The cap above the dephlegmator MUST be vented, either "Kaboom".
Indeed, a sight glass isn't compulsory, but very useful because you can see when the reflux starts.
Without a gate valve and a larger Liebig, the reflux ratio will NOT be 'pretty small' but high and not adjustable, the final product is going to be nice, but the run is going to take time, hence no need to have a stripping run either. Normally, you don't need a stripping run with a reflux still anyway...

[Garouda]

it looks like I'm quoting the book, otherwise tell me why I would have mentioned it ???

Because you may have also had personal experience of badly made "small, temperamental needle valves that can be difficult to procure and which often
change their settings with temperature." This doesn't seem to be the case.

I wrote that I fortunately changed my mind and eventually decided to build a VM head instead. I still have an unused needle valve, top US quality, in a drawer ! Furthermore, I made that decision when I saw my slanted plate head in front of me. I recently slaughtered it because I needed the ferrules to enlarge my gin basket....
You mentioned my personal experience, well, indeed, so far my personal experience tells me I made the right decision, a VM set up is the right option !

That description of needle valves is BS in my opinion.

That's your opinion, I hope you don't mind if I give more credit to what Nixon and McGraw wrote in their book, they seem to have the right qualifications, the first is an engineer and the latter, a research scientist. I strongly recommend that book to every hobbyist who wants to make their own 'booze'.
This would have made this thread about VM, CM, and LM, redundant by the way...
A needle valve is made of metal, and by definition the size of the metal changes with changes in T°, this is not BS but physics.
THE COMPLEAT DISTILLER
Published in New Zealand in October 2001 by:
The Amphora Society
PO Box 51-231
Pakuranga
Auckland 1706
New Zealand
ISBN 0-473-08135-0
Don't ask me why they named it The Compleat Distiller

[drmiller100]

The fores and heads are taken off through the LM take off. WK they never go through the VM takeoff. So when you take the hearts off through the VM takeoff they are not tainted by the fores and or heads. An LM head can compress the fores and heads better then a VM. But the VM can take off a cleaner heart section and compress the tails better. So the two working together in the same still. Make a better product. Your getting the best of both stills.

how does one compress better than the other?

Hey squiggle , this is my take on it .
First off , I agree with you that all head types should be able to achieve the same compression . …Iff’n thats your point

The compression is done in the packing and is a function of Reflux ratio.

But back to the quote from PP .

As any pot stiller will know , the amount of vapour slowly declines as the run progresses ….. same thing happens during a reflux run .
In the VM , the declining vapour will still be split evenly as the run progresses , but the refux ratio will remain the same from start to finish .

However in an LM , the Liquid takeoff remains constant ( as set by the needle valve ) while the vapour declines , this means there is less vapour being condensed and returned as reflux. Therefore , the reflux ratio is reducing as the run progresses . This means that the compression slowly decreases as the run progresses .

OK , thats what happens if we set it (the needle valve ) at the start and just let it run until the end without touching it .

But if an LM is constantly tweaked throughout the run to maintain a constant reflux ratio ( by slowly reducing the takeoff rate ) , it will achieve the same compression of tails as a VM or any other correctly operated still head .

Me , I’m a lazy bugger and I can’t be stuffed with tweaking still throughout the run …. Thats why I prefer the ease of running my VM

Set and forget Baby

So in regards to prairiepiss’s quote , it is correct , but only under certain conditions and shouldn’t be taken at face value that VM is better than LM at compressing heads .

Most LM reflux stills do indeed control how much product is pulled.

A simple design change Can be made to control how much reflux gets sent back down the pipe.
Excess is taken as product.
In this case once heads are concentrated and removed the rest of the run is set and forget.

This is easily done with an offset condenser.

ch

[Terrenum]

Thank you for this forum and discussion.
I have the AlcoEngine and I am able to get 96% pure alcohol.
I am an advanced winemaker and also have a microbrewery so quite at ease with wash, mash, etc.
I do have one question for fellow members here as I am quite green in distilling.

Once my wash is done, my plan is to run it at least twice to get a very nice neutral for gin.
The instructions for this LM device is that you start collecting when the temperature is stable around 78-79C, get rid of the first 100ml (20L wash) and then collect everything until the temperature increases 1 degree. This is when you're apparently done... I understand this for the spirit run and to collect only the hearts, but when I do the first run to get my low wines, I don't want leave behind any potential alcohol. Can I run this all the way up to 98C for the first run?

[Sporacle]

By all means keep an eye on your temp,
Keep a closer eye on your collection rate and make sure you have enough vessels so you can make your cuts.
Good luck

[Saltbush Bill]

I have the AlcoEngine and I am able to get 96% pure alcohol.

Im not sure that is possible using such a short reflux column, that is unless you have modified the column to be longer. If it were that simple to people wouldn't be going to the trouble of building much taller reflux columns.
Have you temperature corrected that 96...?
a 1 degree change in temp is a good indicator, but a better one is your taste buds.....with practice they will pick up a change first......collect in small jars.

[Terrenum]

I have the AlcoEngine and I am able to get 96% pure alcohol.

Im not sure that is possible using such a short reflux column, that is unless you have modified the column to be longer. If it were that simple to people wouldn't be going to the trouble of building much taller reflux columns.
Have you temperature corrected that 96...?
a 1 degree change in temp is a good indicator, but a better one is your taste buds.....with practice they will pick up a change first......collect in small jars.

It could be the temperature. I may have not corrected that time.

May be my question wasn't clear; it's more about using LM column for a stripping run. Can you run it until 98C?
For neutral, I understand you can rely on the 1 degree variation or taste buds.

[Yummyrum]

AFAIK those stills have a restrictor in the outlet that sets the reflux ratio , so the still can’t really be used for stripping . I believe some come with an optional oversized restrictor but it still isn’t a true Potstill unless you can bore out or remove the restrictor . Then you should be able to use it as a Pot still .

You could just go buy a nipple from a plumber or hardware. store to replace the restrictor if you don’t fancy drilling out the one you have .

The temp is a reflection of the ABV at the top . Once all the alcohol is removed and the reflux action can no longer maintain the high ABV , it will start to fall and as a tesult , the temp will start to rise .
So yes it is possible that the temp at the top will get to 98°C .And certainly , without the restricter and running as a Potstill it will …. Just like a real one

I would also agree with Saltys comment above though with regard to stopping when the temp rises by a degree .
This is shutting the stable door after the horse has bolted .
The compressed tails will already be coming over at that point and contaminated your collection if you are not using multiple jars to collect in .

The manufacturers of the still assume that the operator has no experience and therefore will not know when to stop collecting . So they say stop once the temp has risen 1°. Most people wouln’t taste it so they get away with it .

I urge you to actually have a taste of that stuff coming out the spout when you see the rise in temp .( get a half a teaspoon of water and hold it under the spout and collect a few drops and taste) .
I promise you once you have tasted that vial shit , you will switch to using small jars so next time so you’ll be keeping it out of the mix .

Also regarding the initial cut . Have a taste of that first stuff that comes out after you have discarded the recommended 150mls or what ever it is . I think you will dicide to discard quite a bit more .

[Terrenum]

AFAIK those stills have a restrictor in the outlet that sets the reflux ratio , so the still can’t really be used for stripping . I believe some come with an optional oversized restrictor but it still isn’t a true Potstill unless you can bore out or remove the restrictor . Then you should be able to use it as a Pot still .
E36DE448-FF63-4294-B271-07F9532437C9.jpeg

You could just go buy a nipple from a plumber or hardware. store to replace the restrictor if you don’t fancy drilling out the one you have .

The temp is a reflection of the ABV at the top . Once all the alcohol is removed and the reflux action can no longer maintain the high ABV , it will start to fall and as a tesult , the temp will start to rise .
So yes it is possible that the temp at the top will get to 98°C .And certainly , without the restricter and running as a Potstill it will …. Just like a real one

I would also agree with Saltys comment above though with regard to stopping when the temp rises by a degree .
This is shutting the stable door after the horse has bolted .
The compressed tails will already be coming over at that point and contaminated your collection if you are not using multiple jars to collect in .

The manufacturers of the still assume that the operator has no experience and therefore will not know when to stop collecting . So they say stop once the temp has risen 1°. Most people wouln’t taste it so they get away with it .

I urge you to actually have a taste of that stuff coming out the spout when you see the rise in temp .( get a half a teaspoon of water and hold it under the spout and collect a few drops and taste) .
I promise you once you have tasted that vial shit , you will switch to using small jars so next time so you’ll be keeping it out of the mix .

Also regarding the initial cut . Have a taste of that first stuff that comes out after you have discarded the recommended 150mls or what ever it is . I think you will dicide to discard quite a bit more .

Thank you so much for this detailed reply. It totally makes sense.
I assumed that within the 1 degree variation, I would collect very little heads and tails, but I understand they are really compressed and I probably get more that I want! it does make sense.
I will definitely collect in small jars from now on. I need my neutral to be excellent!
Getting a nipple from hardware is a great idea for a stripping run. Would also save me some time I assume.

Once I can make great neutral, I do have a nice 4 gallons copper pot still that I use for my gin, brandy, whisky, etc.

I have used it many times and I am getting better with cuts.

Regards

[Yummyrum]

If you already have a Pot still head , why don’t you just use that for stripping your wash ?

The whole purpose of a stripping run is to remove the bulk of the water as quickly as possible . So you might want to experiment and see which one runs faster , your pot still or the reflux still with no restrictor .

[Saltbush Bill]

As above strip with the pot, use the reflux still to make the neutral....the the pot again to make the gin.......that is the way to do it.
For the best clean neutral use Shadys Sugar Shine recipe.
Rather than relying on temp to tell when to stop stripping, buy and use a Alcometer.......many people only strip down to 40ish% at the spout when stripping neutral washes........personally I go lower ......I cant see any point in leaving that much good ethanol behind.

[Yummyrum]

.....many people only strip down to 40ish% at the spout when stripping neutral washes........personally I go lower ......I cant see any point in leaving that much good ethanol behind.

Same here Salty. A reflux still will do a much better job than any cut you might do on a Pot still stripping run .Strip it all out and let the Reflux still squeeze out the good stuff

[Saltbush Bill]

Exactly Yummy..........stopping early for What?
A reflux still that won't or can't hold back tails to the bitter end isn't worth owning.

[Terrenum]

Thank you all for your input.

Unfortunately the pot still is at a different location and this is why I was inquiring about stripping with the AlcoEngine column.
I should be able to have both stills at the same location in the future but couldn't wait to have access to the pot still to do the stripping run.
I did use the pot still to do a stripping run before and went all the way down to 20%. When I make my brandy, I only use the pot still, do a first stripping run down to 20, then run my spirit run and collect in multiple jars to facilitate cuts and blend final product.
Cheers!
Thanks again

[Poitín Sue]

I'm gonna ask a really thick question. I've a rough idea what different stills do, I like making both neutral and whiskey and it seems to keep that a ccvm is perfectly capable of both.
I can't, weld, solder or braze....though my ex mother in law often said I was brazen. (A brazen something...)
Anyway am I right about the ccvm being a really good pot that can be easily turned into a really good reflux?

[Sporacle]

I'm gonna ask a really thick question. I've a rough idea what different stills do, I like making both neutral and whiskey and it seems to keep that a ccvm is perfectly capable of both.
I can't, weld, solder or braze....though my ex mother in law often said I was brazen. (A brazen something...)
Anyway am I right about the ccvm being a really good pot that can be easily turned into a really good reflux?

Yeah it's a simple swap.
I remove my packing, take out the RC and remove the RC section and blank cap the top of the T.
Pot to CCVM change takes very little time if...... and it's an important if. It needs to be modular

Edit, have a look at Kimbodious and his modular CCVM

[Poitín Sue]

Yeah it's a simple swap.
I remove my packing, take out the RC and remove the RC section and blank cap the top of the T.
Pot to CCVM change takes very little time if...... and it's an important if. It needs to be modular

Edit, have a look at Kimbodious and his modular CCVM
[/quote]

Thanks sporacle.
I think I could manage that- even though I'm not entirely sure what a tri clamp even is.
Could I be a real pain and ask if there's somewhere where there's a precise plan with a precise shopping list for parts. I've read loads, god knows how I've suffered...mbut I'm no closer to starting a build

[elbono]

About any of the recent reflux designs can be run as a simple pot still by removing the packing and changing the arrangement a bit. Probably a CM would be more difficult but not much.

A VM or CCVM can be put together with stainless spools and a valve for VM and condensers made with CSST. All available on Amazon or elsewhere. Look for old posts by dad300 (circa 2012?) and you'll find lots tinkertoy alternatives no soldering, welding or such skills needed.

My condensers are CSST because they were easy, a wound copper tubing reflux condenser and proper leibig or shotgun product condenser are on the todo list but I'm in a different rabbit hole currently.

I put together a CCVM because it was easy and cheap, a valve to make it a VM doesn't add that much cost though.

[elbono]

These are ferrules and the triclamp that holds them together.
https://a.co/d/73fVOBw

This is CSST. https://www.amazon.com/dp/B012TPJ7HK?re ... b_ap_share

These are spools.
https://a.co/d/2wMsThn

Learning the lingo is half the battle in any new interest.

[drmiller100]

On a lm still turn off the reflux and it is a.pot still.

[Saltbush Bill]

On a lm still turn off the reflux and it is a.pot still.

Turn the reflux off on a Boka which is an LM and you will have hot ethanol vapor spewing out of the top of it.
Are you sure you don't mean a CM ?

[Poitín Sue]

These are ferrules and the triclamp that holds them together.
https://a.co/d/73fVOBw

This is CSST. https://www.amazon.com/dp/B012TPJ7HK?re ... b_ap_share

These are spools.
https://a.co/d/2wMsThn

Learning the lingo is half the battle in any new interest.

That's very helpful- and it took a bit of effort!
Thanks....I'm dedicating my next run to you

[Jabman]

I can't, weld, solder or braze....though my ex mother in law often said I was brazen. (A brazen something...)
Anyway am I right about the ccvm being a really good pot that can be easily turned into a really good reflux?

Maybe I could weld/solder, but not want to. So I building this setup right now. Have soon parts to VM, so I can change this VM/CM or pot still in minutes.

(assebled just to take photo and take measures! Pipes etc obvious cannot be pending like that when use.)

This is modular and all parts you can order aliexpress. This can easily modify to VM, LM or pot still. In photo it is on CM mode. Kettle you can find many names/brands (you maybe need SCR to control power) and lid with hole to take 2" tri clamp connector can be found ali.

To mod this CCVM, maybe you need to roll your own cooling coil, I dont know this can be found ali, but soldering is not necessary when doing that.

If you buy this from ali, be aware that you maybe need extension to column too, in photo is only just under 20" (50cm) and connectors should be replaced bigger. And gaskets change to ptfe (ali again)

I just did test run with only with 20"/50cm column and it gave around 93-94% ABV not bad, packing tiny lava rocks.

Drop me PM if want hear more, this maybe getting OT here.

Oh, and CM, you can turn to pot still on fly if you like, just shut down cooling water to dephlegmator

[Poitín Sue]

That's absolutely lovely jabman. Sounds like you really know what's going on.
What's your preferences...cm or vm
Do you mind if I ask what's the rough cost?

[drmiller100]

On a lm still turn off the reflux and it is a.pot still.

Turn the reflux off on a Boka which is an LM and you will have hot ethanol vapor spewing out of the top of it.
Are you sure you don't mean a CM ?

Ummm. No I'm not sure at all???

I go back to the first post on this thread and it says lm. And if you turn off thw reflux it is a pot still.

EDIT. I am wrong. If you open the product port on that still all the way it is a pot still.

Back when I ran mostly LM. But I managed the reflux back into the column with a needle valve not the product pulled off the rig.
I call the reflux the liquid etoh going back down the column. I don't call the cooling water the reflux. But maybe I have terminology wrong.

[Jabman]

That's absolutely lovely jabman. Sounds like you really know what's going on.
What's your preferences...cm or vm
Do you mind if I ask what's the rough cost?

I will test them all what I can and prefer that which is easiest to control. CM need steady flow and temperature of water on dephlegmator, VM as I understand is easier to that part. CCVM sounds interesting, I will test that too later, but I need little extension to "tee" part, where I put cooling coil.

Parts around 375 euros (ali) and extra stuff I didn't calculate, connectors, electronics, packing etc. which I can buy locally, maybe 100 euro more? And boiler I had before, didn't count that. Shipping to here was expensive, basic column parts shipping costs was more than 50% of price (parts 80 euros, shipping 95). Oh, and my list missing the connector to lid 2" tri clamp that fit 51mm hole, I dont remember how much that cost. 30 euros? Bought that years ago.

All prices, includes shipping costs, to your country, it might be much lower.