How I Run My VM/LM Still

[Lester]

Does anybody here run their still this way?

I am making vodka using a 2" x 4' column with a proportional splitting head which allows me to vary reflux ratio anywhere between 100% reflux down to zero reflux.

During several runs I have seen that it is possible to take out product very fast during the early hearts (3.7 liters per hour when using minimal reflux with a boiler charge of 30%~40% ABV), on a 2" column.

The premise is this: As long as the vapor temperature is held constant to within 0.1-deg C then I can take out alcohol at azeotropic conditions. Sure I lose column stability but I can easily restore that by doing 100% reflux for a few minutes, then take product out again. I do have several thermometers on the column and these tell me the purity of the alcohol in there, and also when I need to reflux some more.

Towards the end of the hearts When my boiler temperature is >98 deg C, I do 100% reflux for some time then take out the remaining alcohol at zero reflux, open valve all the way until the vapor temperature increases by 0.2-deg C then shut down. I have been able to shorten my run time by using my still this way but I have to watch it and adjust the splitting valve as needed to keep the vapor temperature down.

I am now considering using this same "dump" method (minimal reflux, right after doing equilibriation) for taking out the heads. If the column has done its job then all the heads should be up there ready to be taken out in a few dumps rather than slowly like a few drips per second. I can imagine that the column is a separate heads column while the heads are up there....... just imagination.

What do you guys think?

[Maritimer]

Hi Lester,

Reading your post was like reading the description of a computer program. Are you using a microcontroller (other than your head)? You're an imaginative experimenter.

M

[Lester]

Are you using a microcontroller (other than your head)?

Not yet, but that's the plan. A stepper motor can drive a lead screw for the splitting valve.

[DAD300]

People have, had, tried separate heads chambers before...

But first...thermometers and temperature, do not tell you the purity of your alcohol. Nor do alcoholometers.

If you fill the heads chamber and start to take off heads from it, what do you think happens in the lower column as the pressure changes? Or, how can you segregate the fores and heads in that chamber and not cause a pressure change below?

You cannot maintain a .1 temp over takeoff. Every time you crack the valve for takeoff, every reflux cycle, you destabilize the column.

Maritimer, you let that go too easy...help him out with your ideas...

There are other threads here with great debates about stacking, vapor separation, column equilibrium...

My position is this...for a known boiler charge and system, you should know the amount of heads waste you are going to collect. If you can get fores and heads to the top, take them off asap and then once you have removed most of the fores and heads, if you need to go heavier reflux in order to attain a desired ABV, do so.

If your column won't make the abv you desire without excessive manipulation, you should work on your column, not the manipulation.

Lester, you have gone to the dark side...theoretical manufacture of elemental ethanol for the express purpose of science.

Please come to the light....ancient applied alchemy of making great tasting, while technically safer, booze for drinking. If you have a method that makes a better drink faster, you will get the Nobel Peace Prize.

[Lester]

But first...thermometers and temperature, do not tell you the purity of your alcohol. Nor do alcoholometers.

If I know my wash and have characterized how it behaves in the column while distilling then I can rely on temperature while I run the still. I refer to the vapor chart here: http://homedistiller.org/forum/viewtopi ... =1&t=10158

You cannot maintain a .1 temp over takeoff. Every time you crack the valve for takeoff, every reflux cycle, you destabilize the column.

As long as the vapor temp is within 0.1-deg C then I take out product. If not then I reflux. It doesn't matter if the column is stable or not. All I'm after is the alcohol.

My position is this...for a known boiler charge and system, you should know the amount of heads waste you are going to collect. If you can get fores and heads to the top, take them off asap and then once you have removed most of the fores and heads, if you need to go heavier reflux in order to attain a desired ABV, do so.

That is my position also. Since I use the same wash every time then I know how it will distill. I fully agree with you on this one.

If your column won't make the abv you desire without excessive manipulation, you should work on your column, not the manipulation.

I'm getting there, slowly. But don't you think it's great to get almost 1 gallon per hour of 95% ABV out of a 2" column? What's your take off rate on your 3" column? Can you get 2.25 gallons per hour of 95% ABV out of it?

..... If you have a method that makes a better drink faster........

Yes this is all I'm after. But if somebody wants to give me a prize then who am I to refuse?

[Lester]

I do know that a lot of people here want to run their still in a constant manner, set the take off rate (a constant rate) then wait for the last drop to come out. I see this as a linear way of doing things.

But the alcohol inside the boiler (as it depletes from the wash) behaves in a non-linear fashion so why take it out in a linear manner? There's a lot of alcohol for the taking during the early hearts so I say let 'er rip while you can!

Nature behaves in a non-linear fashion, logarithms come to mind. I'm trying to exploit this behavior in the best way I can using my method. Piece-wise approximation yes, but it's a better fit than a purely linear method.

[Maritimer]

Lester, you have gone to the dark side...theoretical manufacture of elemental ethanol for the express purpose of science.

Please come to the light....ancient applied alchemy of making great tasting, while technically safer, booze for drinking. If you have a method that makes a better drink faster, you will get the Nobel Peace Prize

Lester,

I don't want to spoil your thread with more of this nonsense. DAD is writing the book on supernatural distilling. He is the evangelical preacher at the Church of DADology of the 3.00 Spirits, and he's always looking for converts.

Please keep on experimenting.

M

[Lester]

Thanks Maritimer! That's funny!

==================================================================================

I have taken this chart (with due credit to Hookline).............

.......... and flipped it.

I then edited the legends on the graph. Horizontal is now "Time" while vertical is "Reflux Ratio". I can now use this as another guide while I distill, yes? And please do notice that the blue line is not a straight line......

This graph now tells me how much reflux I need to do anytime during the run. I don't think I need to reflux anymore than what is needed to attain azeo. This is just an approximation but I hope you folks get the concept.

[DAD300]

A gallon of azeo an hour from a 2" column would is fantastic, even starting with low wines of 40%.

Yes, I can get a gallon an hour the first hour, and about 3 more quarts the second hour as the alcohol depletes itself, from my 3" x 36" VM. From a 14 gallon charge at 12%, there is only ~seven quarts of azeo there. If I through in a gallon of feints with 13 gallons wash, I could get another full gallon the second hour. before unusable tails set in.

I've never started with 40% low wines...don't have a reason to do strip runs and hate the idea of putting feints back in the boiler.

But gas on to gas off, my run is only about 3-3.5 hours at most and after cutting and blending, I'll easily end up with 3+ gallons of drink.

Linear or non linear, I see no difference. I can fire everything up and let it run for 3 hours, while I watch, or I can fiddle with heat and valves, the same boiler charge for 10 hours and make myself feel like I did it. Think that by cutting the run time, you could save 30-50% energy!

I know what is going to come out of the still and when it will come out. I collect it all and the next day blend the good parts for the best drink.

It may be an age thing...but the pure science approach leaves me cold. And I'm willing to bet most that keep distilling over years, will find a method that works and sit back with a good drink.

If it works for you...fine. But some one needs to "PREACH" that there is another way, that accomplishes better, safer than commercial and how efficiently it can be done.

In the last month there have been three flaming debates about this same subject and you ask, "does any one run their still this way?"

You say your headed toward a computer program. Do you know harry Riku and the ARC program? Why not read up on Odin and his highly automated still? He has truly maxed out the automation and the column in one machine.

I'm not against experimentation at all...but please show me something new, better or cheaper.

I'll be off for a few days...love you guys.

[Jacksonbrown]

One option would be to use use a temperature probe at the take off point to send a signal to a pid controller and use the output of the controller to drive the valve position.
So long as you don't have reflux flowing over the probe I don't see why it wouldn't work.
I don't think this would be very hard but it might cost a few hunj to get the bits and pieces. PID with probe and thermowell could be had for under $50 but the driven control valve, FIIK?!?

Weather or not you get the value out it the system is a question for you but it sounds like a cool project.

Personally I don't really care about the ABV, it's the other stuff I want to control the level of and that system would give very little reflux at the start. Perhaps run it manually until the heads are removed then let the PID look after it.

[Maritimer]

Hi Lester,

I've gone over some of your previous posts to get an idea of your equipment. If I understand, you went from a conventional VM still to the proportional splitting head. You had poor control over the reflux ratio in the original configuration, but I don't understand how you were controlling the RR.

My still is a very conventional VM with a gate valve to control RR. One of my first tasks was to instantaneously measure the RR. I used the temperature differences between input port and output port of the reflux and product condensers, so the same principle would apply to your two condensers. This would allow you to measure--and control--the RR precisely.

I'm an old retired guy, and I don't (can't) drink much anymore (but I sure would like to!), so speed is not a concern I've considered. All I want is neutral that won't give me a headache, so slow and pure has been my path.

Hi Jackson,

I'm a big fan of microcontrollers. Since programming a PID loop is quite easy (or you could lift the code from somewhere), and since Lester's description of his protocol measures/reacts to lots of conditions, I would think that a dedicated PID controller would be too limiting.

And DAD,

Preaching the value of experimentation is fine. But preaching cockamamie theories that contradict two centuries of scientific research and natural laws is doing a disservice to your readers.

M

[Jacksonbrown]

Hi Marimer,

The PID controller I use has an auto-tune function so it teaches itself the best way to maintain the process variable. Very easy and tailored the specific system.

My understanding of the OP is that Lester isn't interested in his reflux ratio, purely in maintaining a set take off vapour temp and thus a consistent ABV.
Only one temperature transmitter would be required for this IMO assuming the heat input isn't tweaked through the run.

Regardless of the flow direction or volume, the vapour in that chamber should all be at the same temp so how do you work out your reflux ratio?
If I've misunderstood perhaps a small diagram might help.

[Lester]

Hello Folks,

I struggle with the English language when trying to get my ideas across (I do my thinking in my native language then translate it). Let me sumarize what I am trying to say.

I got very fast take off rates on my 2" column. I think (not sure) it is due to 3 reasons:

1. With a proportional splitting head I can go down to zero reflux. The conventional VM can only go down to 1:1 RR, some can only do 4:1 RR. By going to zero reflux I can double the take off rate, hands down. Here's my still:
http://homedistiller.org/forum/viewtopi ... 3&start=60
Now before someone misunderstands me again, I only use zero reflux at the end of the run. When taking out mid hearts for example I use 1:7 RR. That's 1x for reflux and 7x out the product line.

2. I have installed a reboiler inside my boiler to catch the reflux falling out of the coulmn. I have measured the liquid's temperature in this reboiler and it goes down to 80.5-deg C which translates to ~70% ABV. low wines charge in the boiler. This alcohol in the reboiler gets boiled off ahead of the wash below and gives the column much more alcohol to start with, so minimal reflux (about 1:7, which can't be done with a conventional VM) is enough to get azeo at the output. Here is my reboiler: http://homedistiller.org/forum/viewtopi ... =1&t=43653
And here's how I made my thermometers: http://homedistiller.org/forum/viewtopi ... =2&t=43379

3. Running my still in the manner I described in the 1st post of this thread allows me to exploit item numbers 1 & 2 above. So I get very fast take off rates (3.7 liters per hour) using only a 2" column. That is just as fast as Dad's 3" column which has 2.25x more area and a lot more power input. I think I can go a bit faster and will try to do so once I get a new propane burner.


I attribute the fast take off rate to the COMBINATION of items 1, 2 & 3 above.

As to automation, I can go for it later if I want to. Automation is not the topic of this thread.

While I do understand that some folks are happy with slower rates, in my case fast take off rates are desirable and it is my goal.

Which brings me to my first sentence in this thread: Does anybody run their still this way? I don't think there's a lot of folks who are using proportional splitting heads.

[Lester]

Dad300,

As for being on the "Dark Side": Technology has been my bread & butter for the past 30 years. I am retired now, 2 of my 3 kids finished with college. My first job was with Intel, the microprocessor company.

So Dad, I have always been on the dark side and I see nothing wrong with it. But I can relate to how you struggle with it. I don't.

[flyingdutchman]

Hi Lester,
I love your reboiler idea and have no doubt this increases your ability to have a faster take off rate since your not losing that distillate back to the boiler.

My friend has a Nixon Stone offset 2" column. It has about 3' of SS packing on an insulated column and a 15 gallon boiler. Its not that we want to run it slow but with his setup we find that it requires a minimum reflux ratio to keep the ABV upwards of say 93%-95%. On his setup, if we decrease that RR by increasing the take off rate the ABV drops sharply. Same story if we increase the heat input and the takeoff rate.
I would like to ask..
1) Could you post an image of your rig especially the proportional splitting head?
2) Is this the basic design here? http://homedistiller.org/forum/viewtopi ... 4#p7120884
I am not sure I understand how it operates and am curious as to how this is different in its ability to control reflux rates vs say a Nixon stone offset head LM system with dual valves http://homedistiller.org/forum/viewtopi ... 15&t=20811.
3) How are you calculating your reflux ratios with the proportional splitting head?
4) Why not have 2 or even 3 thermo wells in your column ( base, middle top) that way you could monitor the temperature gradient across the column and use this to determine your optimum takeoff rate without too much disruption to the over all equilibrium of the system? This might possibly eliminate the need to re-equilibrate your column.

Thanks

PS
Its not a binary system but it might simplifiy things if we think of it as one (just ethanol and water). I believe Initially the ABV of your boiler charge is high. But as time goes on the composition of the boiler charge is changing because we have an ever decreasing mole fraction of ethanol. So it make sense that as you say you need less reflux at first but more later in the run.

It has been said this also may have some implications for the RR of some LM systems because as the mole fraction of ethanol decrease the Latent Heat of Vaporization (per weight basis) might also increase. If the rate of vapor production decreases but we do not adjust the collection rate accordingly we might have an ever decreasing RR. Which goes hand in hand with using column thermo temps as feed back on how to adjust collection rate/RR.

[Lester]

Hello Flyingdutchman,

1) Could you post an image of your rig especially the proportional splitting head?

Scroll down this link for some pics: http://homedistiller.org/forum/viewtopi ... 3&start=60
Also here: http://homedistiller.org/forum/viewtopi ... =2&t=43379

2) Is this the design basic here?

not really but that can be used as well

3) How are you calculating your reflux ratios with the proportional splitting head?

I don't need to calculate. I have a linear scale on my valve which tells me the relative position of the sliding disc inside the horizontal tube. You can see the scale here, further down on this page, last pic: http://homedistiller.org/forum/viewtopi ... 3&start=60

4) Why not have 2 or even 3 thermo wells in your column ( base, middle top) that way you could monitor the temperature gradient across the column and use this to determine your optimum takeoff rate without too much disruption to the over all equilibrium of the system? This might possibly eliminate the need to re-equilibrate your column.

I actually have 4 thermometers on my column.
1st is located 1/3 up the column
2nd is located 2/3 up the column
3rd is in the vapor path, a regular digital thermometer with 0.1-deg C resolution
4th is in the vapor path, a narrow-band, expanded-scale thermometer with 0.4-deg C full-scale, 0.02-deg C resolution

In addition to those 4, I have a thermometer in the boiler, immersed in the wash
plus another thermometer immersed in the liquid of the reboiler

So yes I have a good image in my head of what's going on while I run my still.

[flyingdutchman]

AH
I believe I see the VM/LM part now and a cooling tower to boot. That's a great design!

[Lester]

Flyingdutchman,

Here's a sketch of a proportional splitting valve.

The horizontal tube has a slot cut on it's side, 50mm x 12mm on my column. Vapor passes through this slot and goes out to either end of the tube.

The disc goes inside the tube and can be positioned anywhere on the slot by simply sliding it inside the tube. This way I can split the vapor to the left or to the right, in any proportion I need, without having the need to calculate RR. And that vapor split stays constant regardless of how much power I throw at the boiler. Good eh?

One end of the tube goes to a reflux condenser (2 layer coil) while the other end to a product condenser(Liebig).

And yes indeed that is a cooling tower.

[Maritimer]

Holy Cow, Lester!

Those are amazing numbers, way beyond anything my plain old VM could do! I don't understand how I missed your LM/VM thread. Oh yes, that was when I got Mathematica.

When you are running at 1:7 RR, that would seem to be almost in pot still mode. Do you get tails in the product?

Hi Jackson,

I calculate the RR in my VM by using the fact that the same coolant flows through the reflux and product condensers in series. I measure the coolant temperature drop across each condenser (that is, the difference in temperature between input and output ports). Since the same vapour is going into each condenser, and each has the same coolant flow rate, the power of condensation in each can be calculated. Once the power is known, the mass of each condensation is proportional. I use the definition of RR in The Compleat Distiller, which is RR=mass of reflux/mass of total vapour.

So RR = ΔTreflux/(ΔTreflux + ΔTproduct)

Other definitions could be used, of course.

Here is the development:
http://homedistiller.org/forum/viewtopi ... 17&t=32502
http://homedistiller.org/forum/viewtopi ... 17&t=32860

M

[flyingdutchman]

The disc goes inside the tube and can be positioned anywhere on the slot by simply sliding it inside the tube. This way I can split the vapor to the left or to the right, in any proportion I need, without having the need to calculate RR. And that vapor split stays constant regardless of how much power I throw at the boiler. Good eh?

Its better than good that's ingenious!

I see the images but have to ask...
how are you sealing the control rod (that attaches to the disc) as it exits the condenser/product head?

[Jacksonbrown]

Very tricky! I like it.

[Lester]

When you are running at 1:7 RR, that would seem to be almost in pot still mode. Do you get tails in the product?

I don't get tails in my product. A major reason for this is the response time of my thermometer probes, they are fast, a couple of seconds maximum. A regular digital thermometer will have a response time of around 30 seconds or more, mainly due to the mass of the probe itself. With a 30 seconds response time the risk for tails getting out is big.

I keep an eye on the needle of the thermometer while I run the still, and it climbs slowly as draw product out.

I take product out after I have equilibriated some more. I watch the temperature of the column and also the reboiler and I know when I have a lot of alcohol ready for "harvest". Then I open to 1:7 and get the alcohol out fast. No tails.

[Lester]

I guess this should be on my build thread but here you go Flyingdutchman.

That's a flare nut and a nipple. PTFE tape in between the flared copper tube (short length) and nipple. Tighten as needed. No leak.

Note that the rod on the foreground is only for the pointer. The actual actuator rod is behind.

[flyingdutchman]

Thanks!

[Odin]

I run my stills like this. Stack the column with as much alcohol as you can. This gives you a very stable distillation platform to start with. And increadibly high take-off speeds at azeo purity. When the temperature in the column goes up, restabilize for some time until temp goes down again. Then start taking product out again at a slightly slower rate (thus upping the reflux ratio, to correct for the lower abv wash / low wines you are running).

On heads: I wouldn't take them out at a fast rate, but at a slow rate. Two to three drips per second for perfect compraction.

On your redistillation boiler for the reflux exciting your boiler: on the one hand it is the reason you can collect so fast (with such a low RR). You are introducing a positive feedback loop into the system.

But I feel it is a two edged sword. Yes, it speeds up the process and lets you take off very fast in the beginning. But the 30 to 40 redistillations you need are also there to make sure (especially at high speed distilling) no tails get over. Having the column empty in a re-distillation boiler will, during the second half of the run concentrate higher BP alcs in the column, and can cause off flavours.

Curious to what your experience is with that. And as to what packing you are using.

Odin.

[Lester]

I run my stills like this. Stack the column with as much alcohol as you can. This gives you a very stable distillation platform to start with. And increadibly high take-off speeds at azeo purity. When the temperature in the column goes up, restabilize for some time until temp goes down again. Then start taking product out again at a slightly slower rate (thus upping the reflux ratio, to correct for the lower abv wash / low wines you are running)

.
Great! Now I have confirmation on the method I am using, without having to read through thousands of posts in this forum.

On heads: I wouldn't take them out at a fast rate, but at a slow rate. Two to three drips per second for perfect compraction.

Ok thanks, will keep this in mind.

On your redistillation boiler for the reflux exciting your boiler: on the one hand it is the reason you can collect so fast (with such a low RR). You are introducing a positive feedback loop into the system.

I guess you meant "... reflux exiting the column". No, I wouldn't consider it positive feedback as used in amplifier lingo, if that's what you meant. "Scavenging" seems to be a more appropriate word for what's going on.

Having the column empty in a re-distillation boiler will, during the second half of the run concentrate higher BP alcs in the column, and can cause off flavours.

I am not sure I understand correctly what you are trying to say. Having the column empty? But a properly working column will still be able to sort out those higher BP alcs, even if they are in the column initially. I have confirmed this by loading the column with water before I distill. The column will have a high temperature initially, then the temp will gradually go down which to me is an indication that the column is doing its job. The water in the column gets displaced by the alcohol and so the temp goes down. I imagine that the same holds true for the higher BP alcs vs EtOH inside the column. Lower BP alc goes up the column, always does, always will. Unless I interfere with the natural process.

Curious to what your experience is with that. And as to what packing you are using.

SS scrubbies. Haven't gotten around to fabricating SPP although I now have the tooling to make some. Still need to get SS wire. Later.

[Odin]

On positive feedback: what I see is this: reflux exciting your boiler will have a higher abv than the wash or low wines you are distilling. If you re-distill them and have the gasses re-enter the column from there, you will introduce higher abv gasses into your column, thus creating a positive feedback which is good.

On gathering tails: re-distilling many times means that, with every re-distillation, tailsy alcs are more and more pushed down, towards the end of the column, where they may stack. If you have the reflux exiting (yet exciting) return to the boiler, the tailsy molecules get mixed in with the wash, which is a bigger dilution factor than collecting them in the re-distillation boiler. If you collect them there, they will give you more smearing of tails earlier in the run, especially when using a non-SPP packing. Other than SPP packing just does not give enough re-distillations to keep them at bay.

Temperature in the column is not a good indicator for when tails arrive. Not in your (or mine) approach. With the efficiency boost from the re-distiller under your column and/or with SPP it is (probably) very easy to take any wash abv to 95%. I do not use a re-distiller under my column, but I do use SPP. By upping the RR I can take a 1% wash to 95%+ without any problems. So if I distill a 30% low wines, I can keep the temperature at (say) 78.3 C all the time. Yet ... in the end tails will come over. The more you compact heads and tails, the smaller these factions become. But there is a trade off. And that's that the tastes associated with these factions do blend into your hearts. Good if you want to make a whiskey or brandy, but not good if you want to make a neutral.

This taste smearing does not happen on fairly neutral washes, but it does on taste rich washes.

Another trade off is speed versus purity versus number of re-distillations. If you distill faster at a given number of re-distillations, your hearts will become less pure. Upping the number of re-distillations is the way to compensate for higher gass speeds in the column. That's why using SPP would be your next logical step indeed.

On the re-distillation boiler, re-distilling reflux exiting the column ... is it possible to make a small drain from that? If you take off a few mls after every re-distillation, you will probably get rid of very concentrated tails during the second half of the run.

Just giving it my 2 cents.

Odin.

PS: your numbers of 3.7 liters per hour on a 30 to 40% wash are very good. Given the amount of re-distillations scrubbers give you, I can imagine that it does compromize purity. With the gass speeds associated with the take-off speed you have, you pretty much need to triple the amount of re-distillations not to have smearing. In using 2 kw, I get 3.5 liter per hour out of an 2 incher as well. That's on a 30% low wines charge. If I up the power to 2.8 kw, I can breech 4.5 liters per hour. If I do this, I also make sure there is more reflux going down the column for more re-distillations (closer to 60 on a 120 centimeter of packing).

[Maritimer]

Even the tiniest amounts of congeners give me a headache, so, according to Odin, I would probably get a headache from Lester's neutral.

Lester, if you can find someone who is very sensitive--he or she will avoid dark liquors such as whiskey and will be very picky about even clear drinks like gin and vodka--you could have this person sample your neutral and give you an accurate appraisal of its purity.

That idea of putting a take-off at the bottom of the column is interesting. Might give that a try.

M

[Odin]

M, I am throwing in my knowledge. Lester is the only one who can verify ...

Odin.

[Jacksonbrown]

Hi Maritimer,

I've been thinking about your RR measuring method. Are you assuming only the latent heat of the vapour is being knocked out? How do you account for sub-cooling of the condensate? Surely this isn't constant between your two condensers.