VM, CM, and LM confusion

[luva69r]

LM " Liquid Management. The amount/speed of the spirit leaving the still is being managed /controlled .. in turn that dictates how much spirit is being refluxed..or in other words how much reflux there is....or another way ...what the reflux Ratio is.
Most LM reflux stills use a needle valve to restrict or increase spirit flow. The type in the diagram uses a restricter nozzle arrangement. I'm told they come with 2 different interchangeable sized nozzles.
Ive never personally run that exact still, but I'm told that for a small commercially available refux still they are one of the better ones.
Not good for Brown spirits but fine for vodka / neutral style drinks.

Yes, I use it for neutral. The best thing about it is that there is no needle valve to mess about with. You just keep an eye on the temps. and make your cuts.
I just wasn't sure where it sat, as it doesn't have a seperate condensor. I appreciate your feedback.

[Saltbush Bill]

What exactly can you tell from the Temps ?

[luva69r]

What exactly can you tell from the Temps ?

When the boiler reaches temp and vapour has got to the top, you leave the take-off closed for 10-15mins until the temperature stabilizes and the still is in full reflux. You then open her up and collect your Foreshots and the temp goes up by about 0.2deg c as the Heads kick in. It then stabilises again in the Hearts for about 3hrs and then rises by only 0.2deg c again as it hits the Tails.

[Saltbush Bill]

Yes you are right, temp change at the end of the run will let you know of the arrival of tails on a still like that.
Im not sure that the other Temps are that usefull really, The column will stabalize after 10-15 mins regardless of looking at the thermometer or not.
Relying on temps to tell when fores , heads and hearts are arrived at or end is haphazard to say the least.....small jars , smell and taste are far more accurate.

[bluefish_dist]

Yes you are right, temp change at the end of the run will let you know of the arrival of tails on a still like that.
Im not sure that the other Temps are that usefull really, The column will stabalize after 10-15 mins regardless of looking at the thermometer or not.
Relying on temps to tell when fores , heads and hearts are arrived at or end is haphazard to say the least.....small jars , smell and taste are far more accurate.

+1. While the temps may vary a little at the front end, it does not correspond to a heads cut in my experience. Temperatures on an unknown run won’t make your cuts for you.

Lots of runs of the same product can let you make cuts by volume or time. But that is experience suggesting where you cuts will be. When you do a new unknown run taste is still the best way to make cuts. Even the big boys like beefeater have tasting stations.

[shadylane]

My 2 cents worth
Accurate Temps can be used for estimating the ABV
But ABV can't tell you what the cuts are going to taste like

[Saltbush Bill]

+1. While the temps may vary a little at the front end, it does not correspond to a heads cut in my experience.

Ive never noticed any variation at the front end with a 3 inch Boka, the change at the tail end is fast and cant be mistaken.

[bluefish_dist]

+1. While the temps may vary a little at the front end, it does not correspond to a heads cut in my experience.

Ive never noticed any variation at the front end with a 3 inch Boka, the change at the tail end is fast and cant be mistaken.

I often see a .2 to .3 deg F change between my lowest equilibrium temp and my running temp. I always assumed this was the really light volatiles getting taken off.

[azeotroll]

N00b here. I'm running a 3" torpedo pro column from Mile Hi (https://milehidistilling.com/product/3- ... pro-tower/)

As far as I can tell this is a cooling management setup. ( Quick aside, I don't really know if the design of the reflux condenser has a name, is' a very simple vertical pipe (1" or so) with two lines going to the side for input/output. ) I have two quick questions:

1 - Could i realistically change this to LM or VM by changing the head on it?

2 - In both the LM and VM cases it seems like there is a very good chance developing dangerous levels of pressure in the system while the takeoff is closed down. True? So if I went this route I'd want to add some precautions to address that?

Thanks in advance!

[kimbodious]

Easy enough to make a VM with that still plus a valve between the column and the product condenser. Second piece from the bottom is a reflux condenser, put that piece at the top of the column. Do not put the cap (with the thermometer) back on the top, that leaves the column open to the environment at the top (no pressure issues). As long as there is enough cooling in the reflux condenser there won’t be any vapour escaping out the top.

[Saltbush Bill]

In both the LM and VM cases it seems like there is a very good chance developing dangerous levels of pressure in the system while the takeoff is closed down. True? So if I went this route I'd want to add some precautions to address that?

No still is ever a closed system, they all need to be open to atmosphere at all times , if not you have just created a bomb.
Suggest you look at still build threads until you understand that concept and how stills are built properly.

[azeotroll]

No still is ever a closed system, they all need to be open to atmosphere at all times , if not you have just created a bomb.
Suggest you look at still build threads until you understand that concept and how stills are built properly.

Haha that's what I was scratching my head about. I should have just looked it up though first. Thanks Bill!

[greggn]

( Quick aside, I don't really know if the design of the reflux condenser has a name, is' a very simple vertical pipe (1" or so) with two lines going to the side for input/output. )

That is not the reflux condenser, it's the product condenser. There are many different condenser designs and that one is a "liebig."

Edit: ... and it appears to be undersized for a 3" column. It's going to limit your production rate. Consider upgrading to a shotgun condenser after you become more comfortable running your rig.

[azeotroll]

Edit: ... and it appears to be undersized for a 3" column. It's going to limit your production rate. Consider upgrading to a shotgun condenser after you become more comfortable running your rig.

Thanks! The part I'm talking about is the part in red. I tried to indicate what it looks like inside with the gold fill. Those two lines go straight in and pick up a vertical 1" or so closed pipe. I put the glass section below it and the reflux generally just drips right off of the bottom of that.

I was thinking about adding a little bit of copper packing in there to help slow the vapor down a bit, if I run the 2kw heating element wide open i get a decent amount of product out. The product condenser seems pretty good, even with the cooling water running low the liquid is coming out chilled to below room temp.

[Expat]

...if I run the 2kw heating element wide open i get a decent amount of product out. The product condenser seems pretty good, even with the cooling water running low the liquid is coming out chilled to below room temp.

If I've understood correctly you're running a 3" column, in which case 2kw is definitely under powered for a column of that diameter. For any reflux column (other than plated) a good rule is to fill all of the space below the reflux condenser with packing of some sort; else its not much better than a pot still.

Just to confirm, the water coming out of the reflux condenser should be quite hot, no need to over cool the distillate being returned to the column. The product cooler definitely is over sized for the purpose, likely built to operate in a pot still configuration without the RC.

[Saltbush Bill]

Looks like another of these so called " duel purpose" stills to me....a pot still trying to be a reflux still.
The fact that its modular is a good thing , will let you reconfigure it and add parts if you want something better.
I suspect that refux condenser will only be good for partial reflux so not much good for proper reflux still purposes if / when you reconfigure it.

[greggn]

Thanks! The part I'm talking about is the part in red. I tried to indicate what it looks like inside with the gold fill. Those two lines go straight in and pick up a vertical 1" or so closed pipe.

Whoa, I didn't see that coming.

[azeotroll]

I appreciate the help folks!

If I've understood correctly you're running a 3" column, in which case 2kw is definitely under powered for a column of that diameter. For any reflux column (other than plated) a good rule is to fill all of the space below the reflux condenser with packing of some sort; else its not much better than a pot still.

Yep this is sort of my contraption I put together by running loose on the Mile Hi listings. The main thing I wanted was a starting point and something modular (as Saltbush Bill pointed out) so I could learn and hopefully reuse/recycle parts as I figured out what I really wanted to do when I grew up. I just got everything I need for the 240v hookup except the element, will probably order that in a month or two.

Just to confirm, the water coming out of the reflux condenser should be quite hot, no need to over cool the distillate being returned to the column. The product cooler definitely is over sized for the purpose, likely built to operate in a pot still configuration without the RC.

Yep i had the water coming out of the reflux condenser at 120F for almost the entire run. We're on well water so the pressure fluctuates quite a bit but it was pretty stable.

Yeah I might actually make a smaller version of the product condenser, it's running at a trickle the whole time.

Looks like another of these so called " duel purpose" stills to me....a pot still trying to be a reflux still.
The fact that its modular is a good thing , will let you reconfigure it and add parts if you want something better.
I suspect that refux condenser will only be good for partial reflux so not much good for proper reflux still purposes if / when you reconfigure it.

I haven't been here long enough to know if you always nail it on the head Bill but you did here lol. This was a bit of an impulse buy after probably 5 years of planning to build one. Just got tired of thinking and wanted to start doing haha. I can't say much about the design clearly but it came out of the box like a crown jewel, gorgeous welds and polished from head to toe.

I'm partly in this to geek out as well. This is what my sacrificial run looked like. Temps in F and weights in apprximately grams/ml's. Won't go into the chaos from 11:55-12:30 haha.

[TheBirdmann]

I was thinking maybe it would be a good idea to add slanted plates under the condenser on the VM setup. What do you think?

That would be an LM/VM combo. A few members are running these stills including myself.
The Boka LM keeps the VM clear of heads when collecting product (neutral)... Great rig...

I still consider myself a newbie, but I've been using my 2" boka quite a bit. What do you mean by this? On some of the finer points I'm left wondering, because most instructions or methods I read about online are pot still-related. I've often wondered that if I can control the temp and the reflux ratio, where the heads actually are (if I'm collecting at 174F/78.8C), and how much I need to throw out.

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.

I'm a little new and still a bit confused. Are there separate takeoffs for the liquid on the pate and the vapor above it? In that case where would the vapor takeoff be relative to the edge of the slanted plate; above, centered, or lower?

[squigglefunk]

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?

[Yummyrum]

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 .

[squigglefunk]

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 .

thank you for that explaination, and I don't have a whole lot of experience running a reflux column so maybe that's why I'm confused.

On my CCVM still (I think that's what it's called) The dephlegmator pushes everything down and you "compress" or "stack" (equalize?) the column(sorry if the terms are wrong)... then I turn the dephleg down a tiny bit, until a tiny drip at a time comes off, and you let that drip very slowly until the fores/heads are run off. Then you get a new jar,and turn the dephleg back a little more for a bigger stream and run the "hearts" ... now how exactly are these "tainted" by the fores/heads? There is no pooling in my still path, I made pretty sure of that. Then the "hearts" run will come and as soon the proof drops even slightly you are pretty much into tails. and it drops like a stone, there is not much booze left. All the hearts have been compressed nicely. If properly run I am not sure how you get "cleaner" ?

[Yummyrum]

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 .

thank you for that explaination, and I don't have a whole lot of experience running a reflux column so maybe that's why I'm confused.

On my CCVM still (I think that's what it's called) The dephlegmator pushes everything down and you "compress" or "stack" (equalize?) the column(sorry if the terms are wrong)... then I turn the dephleg down a tiny bit, until a tiny drip at a time comes off, and you let that drip very slowly until the fores/heads are run off. Then you get a new jar,and turn the dephleg back a little more for a bigger stream and run the "hearts" ... now how exactly are these "tainted" by the fores/heads? There is no pooling in my still path, I made pretty sure of that. Then the "hearts" run will come and as soon the proof drops even slightly you are pretty much into tails. and it drops like a stone, there is not much booze left. All the hearts have been compressed nicely. If properly run I am not sure how you get "cleaner" ?

For a “bastard from the bush “ that distills by a creek and uses no measurements to make a batch ,….. you totally have got this .

Yes ,PPs other comment about keeping LM and VM paths seperate to prevent cross contamination from fores and head also doesn’t sit well with me .
I call pedantic BS on that .

Look , I’m a self confessed pedantic wanker …. But hey , I’m calling it on this too . FFS. It’s crap like this which can drive a newbie unnesseccarily mad.

[squigglefunk]

Look , I’m a self confessed pedantic wanker ….

this is why I like you lol!

anyway I don't really use my reflux still much, I don't have a ton of use for "neutral" is it were and maybe I am not the expert on what is "cleaner" I just want to understand as I can remember a while back when I was putting my CM still (sorry I prob called it the wrong thing above) together I has asked about a LM unit that could be added to it (I saw it on a DR GRADUS video...) and many people told me it was achieving the same function as the process I described above? So yeah it makes me go hmm.

[Steve Broady]

FFS. It’s crap like this which can drive a newbie unnesseccarily mad.

Suggesting that there is a certain degree of madness which a newbie like me is required to endure?

[squigglefunk]

Suggesting that there is a certain degree of madness which a newbie like me is required to endure?

all I can do is be me, whoever that is

[bunny]

Suggesting that there is a certain degree of madness which a newbie like me is required to endure?

The sad part about being an excited, enthusiastic newbie is you don't know who's opinions to trust yet.
From my 2 1/2 years of continuous reading and experimenting I find yummyrum's thoughts and opinions to be the most balanced and realistic and fairly unbiased of those that I can actually understand on this or any other related board.

We don't agree 100% on everything, however, you would be pretty safe if you used him as your primary source guide.

[Garouda]

N00b here. I'm running a 3" torpedo pro column from Mile Hi (https://milehidistilling.com/product/3- ... pro-tower/)

As far as I can tell this is a cooling management setup. ( Quick aside, I don't really know if the design of the reflux condenser has a name, is' a very simple vertical pipe (1" or so) with two lines going to the side for input/output. ) I have two quick questions:

1 - Could i realistically change this to LM or VM by changing the head on it?

2 - In both the LM and VM cases it seems like there is a very good chance developing dangerous levels of pressure in the system while the takeoff is closed down. True? So if I went this route I'd want to add some precautions to address that?

Thanks in advance!

1. You can change it into a VM still,
2. therefore you need a cap, with a vent on top of the part with your coil, your current dephlegmator, then below this, you would need a T-junction, a gate valve and a reduction. I do not recommend an LM device, the Bokabob solution was very popular several years ago, and I was even about to follow that fashion, but I changed my mind and luckily decided for a VM head. The big advantage of a VM head is that it indicates clearly that you reached the tails. On the other hand, the needle valve in an LM system isn't stable (The Complete Distiller Nixon and McCaw). Do not forget some packing material like copper mesh and or stainless steel mesh or pot scrubbers. See pictures below...

[Saltbush Bill]

On the other hand, the needle valve in an LM system isn't stable (The Complete Distiller Nixon and McCaw).

Is that from personal experience or are you quoting from the Nixon McCaw book?
If for some reason people are having issues with unstable needle valves then I'd suggest they buy better quality needle valves.
Ive personaly used a fair few needle valves , including on LM stills.....I've yet to see one that was "unstable".

[Garouda]

On the other hand, the needle valve in an LM system isn't stable (The Complete Distiller Nixon and McCaw).

Is that from personal experience, or are you quoting from the Nixon McCaw book?
If for some reason people are having issues with unstable needle valves, then I'd suggest they buy better quality needle valves.
I've personally used a fair few needle valves, including on LM stills..... I've yet to see one that was "unstable".

Not from personal experience, fortunately I eventually decided not to follow the Boka fashion.
It looks like I'm quoting the book, otherwise tell me why I would have mentioned it ???
"A vapour management still head is very easy to build because the concept is so simple, and is a considerable advance on all previous
liquid management techniques that utilize small, temperamental needle valves that can be difficult to procure and which often
change their settings with temperature.
It has three further advantages:
• once calibrated, its settings remain the same
• it maintains a constant selected reflux ratio for any boiler power setting or vapour composition
• the quantity of product distillate automatically reduces at the end of a run when the tails begin to be evident."...
op. cit. p.131