Why do bubble plate columns use a dephlegmator

[tarz]

Hello!

I´ve been thinking about bubble plate designs alot lately but I can´t wrap my head around one thing. It seems that all the bubble plate columns out there use a dephlegmator as the reflux condenser at the top and thus making the entire still essentially a CM still. CM stills are not fun (based on experience and the feedback on this forum) that´s why I´ve built myself a LM reflux still with the column being SPP packed.

However I can´t help but wonder why is that we are (mostly) using a CM setup(dephlegmator) when we could use for example a LM setup on top of the bubble plate column.

To illustrate my question
As-Is the popular (the dephlegmator variation)

Alternative (LM variation)

[Saltbush Bill]

Why are cm bubble plates not fun?.....some people seem.to find them.difficult to run.......others seem to do just fine.....as with all stills it's a balancing act. You just have to find the stills happy zone and not try to force it into things it doesn't want to do.
A Deflegmator only partially condenser things........a condenser , condenses everything.
The job of the deflegmator is two fold....one is to provide reflux.....the other is to sort the different boiling point components of the wash.
See link below
https://www.thermopedia.com/content/691 ... %20gravity.

[Yummyrum]

I use a VM head on my plated still . A LM would work just as well .

To be honest , I couldn’t taste any difference between using my original Deflag and then switching to VM .
Salty is right that a Deflag does provide some separation of vapour fractions , but I think once you put 4 plates under it , the plates are doing the grunt work of separation , not the deflag .

Stick a Deflag on a pot still and you might notice tails being able to be held back .

[tarz]

I thought exactly the same thing that the plates will and should do the vast majority of the separation not the dephlegmator itself.

I now found one LM setup with plates https://ae01.alicdn.com/kf/Af9db629df0f ... 66401N.jpg

[Demy]

I use a CCVM head and bubble plates... I think any system works if used well, actually you are right, the configurations sold are mostly CM system.

[still_stirrin]

The deflag is used to “load” the plates. The (pass-through) style of reflux condenser generates the condensate to first load the plates top down. Once the plates have a level of liquid on them, the rising vapors transfer the heat directly to the condensate (on the plates). As a result, when the plates are loaded the heat load removal duty for the deflag is reduced and the top of the column behaves more like a potstill, simply passing the vapors to the product condenser. The tricky part is balancing the coolant flow to the deflag as the plates do the “work” of separation. Once loaded, the RC could be turned down for a while.

And as the plates and the condensate on the plates heat up through the run, more and more of the hot vapors will progress to the deflag and RC coolant flow will require adjustment to keep the plates properly loaded.

The advantage to a plated column is that it will allow much more flavor to pass through. Typically, flutes have fewer redistillations than a packed column would. And the coolant management of reflux is much more difficult throughout the run.
ss

[BrewinBrian44]

Defleg is one way of doing it and works well, but you must have a consistent water source, or you’ll be very frustrated. If you see any change in water pressure or your inlet water temp climbs quickly, it’s a huge pain in the ass. I used CM when I first bought my plated column, when I was at my old house on city water. If my wife hopped in the shower or ran the dishwasher, I knew exactly how much to adjust the needle valve to keep it steady. My new house is on a well and despite all my efforts, I was never able to solve the pressure fluctuation.

I took yummyrum’s advice and switched to VM. I personally find it to be better than CM as it gives you an extra level of control. Only downside is you can’t really strip the rest of the tails at the end of a run. Im okay with it though as there’s not much alcohol left and by the time I get down that low, most of what’s coming out the pipe is disgusting. CCVM would solve this as you can run it like a pot still at the end of a run. I’ve heard good things.

I already had the parts available to make the switch, which made it an easy choice. My neutral column uses the same VM head.

LM should work fine for you, if you go that route.

[Setsumi]

I run CCVM on my flutes. If you read a bit of Larry's posts you will read he thinks LM brings other opportunities. There is no reason to use a reflux that you are comfortable with.

[tarz]

The deflag is used to “load” the plates. The (pass-through) style of reflux condenser generates the condensate to first load the plates top down.

It makes sense what you are saying however I feel that the same result would be achieved by using any (powerful enough) condenser at the top, be it spiral or a deplegh as long as it is able to knock down all the vapours. The LM or VM head at the top would also ensure that the condensate would fall back on to the plates (i.e "load") and trickle down accordingly to achieve a certain level of liquid on each of the plates.

It´s just that with a LM/VM head we get the added benefit later when we actually want to start taking product out that we can control the output speed instead of trying to balance the coolant flow.


Thanks for the replies all, it seems that it is perfectly fine to use a LM / VM head instead of CM on the bubble plate column, I´ll definitely be looking into this in the future.

[still_stirrin]

It makes sense what you are saying however I feel that the same result would be achieved by using any (powerful enough) condenser at the top, be it spiral or a deplegh as long as it is able to knock down all the vapours.

The LM or VM head at the top would also ensure that the condensate would fall back on to the plates (i.e "load") and trickle down accordingly to achieve a certain level of liquid on each of the plates.

It´s just that with a LM/VM head we get the added benefit later when we actually want to start taking product out that we can control the output speed instead of trying to balance the coolant flow.

Thanks for the replies all, it seems that it is perfectly fine to use a LM / VM head instead of CM on the bubble plate column, I´ll definitely be looking into this in the future.

Don’t misunderstand the effects of the “head type” for running the still. The deflag, or a twisted coil, or even a concentric (Liebig style) reflux condenser would still be a CM head if the water flow rate through the reflux condenser was used to regulate the amount of vapors returned to the plates. This is because the coolant flow is proportional to the heat removal that creates the condensate.

Energy transfer (heat removal) will vary with temperature difference between the vapor and the coolant. In addition, the flow rates (mass transfer) of the coolant and vapor affect the transfer of energy, although we can assume the vapor flow rate is nearly constant and its temperature is likewise stable. So, any variance in the water flow rate (temperature drift or source pressure) will significantly change the energy transfer and as a result, the reflux ratio (which controls the product purity).

A vapor managed stillhead (regardless of the reflux condenser design) regulates the reflux ratio by the vapor split between the reflux condenser and the product condenser. It is not affected by the condenser’s ability to knockdown the vapors as long as it can knock 100% of the vapors that contact the condensing surface (condenser power).

The advantage with the VM is that variance in coolant flow doesn’t affect the vapor split. Likewise, the vapor production rate doesn’t affect the split either. Faster vapor production (higher heat input) would produce faster product at the spout provided that the RC and PC can handle the heat load to (fully) condense the vapors flowing to the respective condensers. And with the RR held constant, the product’s purity will remain constant.

Similarly, the liquid manage stillhead will use the condensate takeoff (product) to manage the reflux ratio since the vapor produced minus the product removed will net the vapor returned to the column. Since this management of the RR requires all of the vapors to be condensed before either returning down the column or removed as product, it will be the slowest to produce product although it will give a very high RR (and product purity).

But, regardless of packing or plates in the column, the reflux head type will control the reflux ratio and the VM is the easiest to “set & forget” to produce a consistent purity. A deflag (CM) is the “classic” design for a plated column simply because it preceeded the LM and VM in design evolution.

The earliest of still designs used a thumper to add an additional distillation to the potstill increasing the %ABV at the spout. The plated column added a series of distillations (each plate being similar to a thumper) further increasing the %ABV at the spout. When the purity demands required many re-distillations, the packed column replaced the plated column and the alternate methods of reflux management were developed.

In conclusion, whether you use a traditional deflag (CM) or a VM or LM to manage the reflux ratio to your plated column, the higher RR will produce higher purity with less flavors. Conversely, a single distillation, ie - potstill, will give the most flavors. The packed columns, on the other hand, are capable of producing a very neutral (clean) product, while somewhere in between them is the plated column (like a series of thumpers) that will produce a product with a lot of flavor and a higher %ABV than a single, or double distillation would.
ss

[SDEngr1]

Truthfully...I can't understand why anyone would not use them.

[tarz]

Don’t misunderstand the effects of the “head type” for running the still. The deflag, or a twisted coil, or even a concentric (Liebig style) reflux condenser would still be a CM head if the water flow rate through the reflux condenser was used to regulate the amount of vapors returned to the plates.

I believe I didn´t misunderstand the running of the still based on its head type. I am familiar how reflux ratio(RR) works for different types of reflux stills (CM, VM, LM) (good threads on this here viewtopic.php?f=1&t=46605 and viewtopic.php?f=60&t=46216 and viewtopic.php?t=13265)

When I wrote "It´s just that with a LM/VM head we get the added benefit later when we actually want to start taking product out that we can control the output speed instead of trying to balance the coolant flow."
I perhaps should´ve added that this controlling or balancing is essentially controling or balancing(and setting) the Reflux ratio.

Hence having an LM or VM head with a condenser that is able to knock down all the vapours moving up will give us an easier time to control the reflux ratio(RR) by giving us a valve to let out as much product as we want. With a deplegh on top of the plated colum we wouldn´t have such an easy time with it as we are soley relying on the cooling water temperature and flow rate (which are certainly more hard to control than a needle valve)

In conclusion and going back to the original question "Why do bubble plate columns use a dephlegmator?" I´d still say (and based on the feedback here as well) there is absolutely no need for it on top. You can have a VM or LM head on top of the plates and it´d be just fine.

[Sporacle]

In conclusion and going back to the original question "Why do bubble plate columns use a dephlegmator?" I´d still say (and based on the feedback here as well) there is absolutely no need for it on top. You can have a VM or LM head on top of the plates and it´d be just fine.

And that's the beauty of this hobby, plenty of people swear by 4 plates for dark spirits and run with a dephlegmator, plenty of guys use a pot.
People love their CM VM LM and CCVM for whatever purpose.and will tell you that theirs is the best type and this is because they know their rigs
This is more about what you are comfortable running and the gear you know and also about the way the still sets up for the individual
Changing the way a still runs by swapping out the dephlegmator for a CM or LM head will not help you one little bit if you don't understand how your still runs

[StillerBoy]

In conclusion and going back to the original question "Why do bubble plate columns use a dephlegmator?"

Because that's what the design, for the production of the end product, calls for.. each style produces a slightly different end product due to how the vapors are managed.. CM and BP (flutes) thou they use a similar condensing system, will produce different results in the hands of an experience operator.. the main issue with those design is the requirement of constant cold water to properly operate them, otherwise are very difficult to operate, and the inexperience operator lack in understanding such..

I´d still say (and based on the feedback here as well) there is absolutely no need for it on top. You can have a VM or LM head on top of the plates and it´d be just fine.

No it will not.. one can bastardize any design/style, but it will not produce the same end result, plus it's operation will also be more difficult than it's original design.. only in the hands of an experience operator, meaning one who hand full understand of how the vapor behavior in each style and how to manage them for the result wanted, will the different by notice..

Mars

[BrewinBrian44]

In conclusion and going back to the original question "Why do bubble plate columns use a dephlegmator?"

Because that's what the design, for the production of the end product, calls for.. each style produces a slightly different end product due to how the vapors are managed.. CM and BP (flutes) thou they use a similar condensing system, will produce different results in the hands of an experience operator.. the main issue with those design is the requirement of constant cold water to properly operate them, otherwise are very difficult to operate, and the inexperience operator lack in understanding such..

I´d still say (and based on the feedback here as well) there is absolutely no need for it on top. You can have a VM or LM head on top of the plates and it´d be just fine.

No it will not.. one can bastardize any design/style, but it will not produce the same end result, plus it's operation will also be more difficult than it's original design.. only in the hands of an experience operator, meaning one who hand full understand of how the vapor behavior in each style and how to manage them for the result wanted, will the different by notice..

Mars

No disrespect Mars, but I disagree with your assertion about bastardizing the design of a flute by using VM or LM on top. I have quite a bit of experience running a flute and have not noticed any appreciable difference in flavor using CM vs VM. Yummyrum also seems to agree here. Yeah sure, like others said above, a CM head does selectively leave heavier vapors behind, while VM splits some off. This is fundamentally different and should make a difference, but I haven’t seen enough to really notice or care. That said, if I didn’t have my inconsistent water source problem, I’d still be using CM.

You have a tendency to remind people that they lack experience. You once did too. Please recognize that we all start somewhere and comments like that, without constructive words on how to improve one’s skills are not helpful to anyone and make you come across as pretentious and rude.

[Saltbush Bill]

You have a tendency to remind people that they lack experience. You once did too. Please recognize that we all start somewhere and comments like that, without constructive words on how to improve one’s skills are not helpful to anyone and make you come across as pretentious and rude.

+1

[Setsumi]

In conclusion and going back to the original question "Why do bubble plate columns use a dephlegmator?"

Because that's what the design, for the production of the end product, calls for.. each style produces a slightly different end product due to how the vapors are managed.. CM and BP (flutes) thou they use a similar condensing system, will produce different results in the hands of an experience operator.. the main issue with those design is the requirement of constant cold water to properly operate them, otherwise are very difficult to operate, and the inexperience operator lack in understanding such..

I´d still say (and based on the feedback here as well) there is absolutely no need for it on top. You can have a VM or LM head on top of the plates and it´d be just fine.

No it will not.. one can bastardize any design/style, but it will not produce the same end result, plus it's operation will also be more difficult than it's original design.. only in the hands of an experience operator, meaning one who hand full understand of how the vapor behavior in each style and how to manage them for the result wanted, will the different by notice..

Mars

Mars, you seem to forget we are in a hobby environment and not bounded by rules you decide on. Second look a bit at Larry's posts. It seems there are definitely LM platers out in the craft business.

Last, if Old Dog put a LM head on his first flute, all would do it that way.

You will be hard pressed to taste the difference in product from a flute with different heads.

[shadylane]

I can´t help but wonder why is that we are (mostly) using a CM setup(dephlegmator) when we could use for example a LM setup on top of the bubble plate column.

A LM still head would work perfectly well.
There's not many of them used, mainly because their less sexy.
I'd like to see somebody start a post about ideas on how to do it.

[jedneck]

I run a lm/vm combo head on my plater

[Stonecutter]

I run a lm/vm combo head on my plater

This site and this hobby never ceases to amaze me. There is SOO MUCH out there. That’s quite the rig jedneck. Cool man

[bluefish_dist]

I thought I had replied to this already, but I guess not. Imho the only reason cm’s with deflags are common is that’s what the big guys do. It’s the easiest design to make really big. It’s one downside is that it requires consistent water flow/pressure. Up side is that it can be controlled from the ground, a big deal when the column is 20 ft tall.

To me a VM is the easiest to run and works fine for packed, bubble caps, or sieve plates. Just doesn’t scale well to big columns. Also requires adjustment at the top of the still which adds cost or complexity to do safely on a tall column. Down side is 1:1 reflux limit. Although I found I never ran even close to 1:1, so for me it was a non issue. I usually ran a 1” valve on a 2” head as it was easier to adjust.

While I built a combination LM/vm head, I found I didn’t like the lm takeoff and didn’t use it much. Occasionally I would use it to pull heads to keep them out of the vm takeoff, but that usually wasn’t with the trouble. I always wanted to try a reverse LM to see how it compared to a vm.

[shadylane]

Here's my thoughts.
Plates only need enough reflux to keep loaded with liquid.
A depfleg works better because it can be turned down to match what the plate needs.

[bluefish_dist]

Here's my thoughts.
Plates only need enough reflux to keep loaded with liquid.
A depfleg works better because it can be turned down to match what the plate needs.

How is that any different than a LM stillhead? Can go from 0 to 100% reflux, just like a cm still.

[DAD300]

The reason to NOT use a deflag is that they are very hard to build and very expensive to buy!

I think building one is a right of passage for the copper builders.

The reason TO USE one, for me is access. As my commercial stills got taller and taller, a deflag made more and more sense. The top of my still is eleven feet off the floor. I can set safely in a chair and adjust the water flow, rather than risking my old bones on a ladder to make changes.

A large enough deflag can stop all vapor passage, just as a CCVM virtual valve can.

[shadylane]

Here's my thoughts.
Plates only need enough reflux to keep loaded with liquid.
A depfleg works better because it can be turned down to match what the plate needs.

How is that any different than a LM stillhead? Can go from 0 to 100% reflux, just like a cm still.

Your right.
A LM can be used above plates.

[shadylane]

The reason to NOT use a deflag is that they are very hard to build and very expensive to buy!

I agree a shotgun style defleg is difficuilt to build.
But there's also the option of building a simple dimroth defleg out of a coil of tubing.

[SDEngr1]

I operate a 4-plated flute still with a dephlegmator and the thing is a dream to operate. I have separate water lines to each condenser and control flow rates using a ball valves on the discharge ends into a small kiddie pool. I use a pulse width modulator and water discharge valves to control my distillation take off and reflux rates and have infinite control without any needle valves involved using a combination of flow rates and heat input. After the main hearts I generally increase the energy input and reflux ratio to keep the tails under control. I generally have around 10% heads, 70% hearts and 20% tails which I consider a very good yield.

[jpparts]

Pretty sure I know the answer, but can a bubble plate be added to a column that does not have a depfleg or any other form of reflux above the plate? I am not looking for a high ABV spirit. 150-160 is good for me. My thinking was if I could get a little reflux action, but not so much as to strip flavor. Instead of doing a stripping run, then a spirit run, could I get something similar with a single plate?

[shadylane]

Pretty sure I know the answer, but can a bubble plate be added to a column that does not have a depfleg or any other form of reflux above the plate?

It takes liquid to make the plate work.
Without reflux there is no liquid.