First run on new flute done! Some questions and comments

[JimBob88]

Hey everyone,

Last night I completed the maiden run on my new flute and while there were some hiccups along the way at the end of the day it produced an AG bourbon that is not horrible. The still is a 4” modular bubble cap flute with a total of 8 plates (only used 2 on this run), the boiler is a 15.5G keg that I welded a 4” flange to so I can direct mount the column and it goes down to 2” after the dephleg. I use a 65,000BTU propane burner for heat. I do have some comments and questions about the run and I would appreciate any insight you all may have. Boiler charge was 11ish gallons of 6.5%.

Comments;
It was easier then I though it would be to balance the plates during heat up and reflux and I was able to cut way back on the heat and they settled right in. A bit of vapour did sneak past but maybe 10ml total before I started product take off.
Once I was ready to pull product off I cut back the water to the dephleg by half and waited 10 mins, nothing, cut back again, wait, nothing. Continue until there was hardly any water flow at all and I had to turn the heat up to almost full blast to get product up through. Ran slow through the fores and into the heads then sped up to a steady small stream for the rest of the run. Ended up with just a squeak under 2L of keepers at 72% after airing and blending. Not to shabby I don’t think. The heads to hearts cut was difficult to find in real time but holyyyyy do you know when tails show up.

Questions;
Is it normal to have to run at almost full blast on your burner with the dephleg cut back to almost nothing to get a small stream of product? On my 2” pot still once things were up to temp I could cut back to 1/3rd ish depending on outside temp and run easy.

How do you all run your cooling water? I went water into product condenser, out product to reflux (with valve) and then out reflux. While it worked ok I had to throttle back my reflux condenser so much that there was not much flow in the whole system which could cause blow by in my mind. Would it be better to set up 2 Y hoses instead and each condenser gets its own supply/relief?

One and done through 1-3 plates how fast are you all taking off product at? Pencil lead steady stream? Drip drip dribble? Or slightly faster then then a pencil lead stream?

Overall I really enjoyed it and providing I can get it figured so I am not blowing through that much propane I think I have found my new favourite still, plus it is fun to watch the bubbles

[Yummyrum]

It is best to split the water so you have independent control of both condensers .

Yes , a trickle of water is pretty typical and controlling it is tricky . Mist of us use a good quality needle valve .

Not sure how your BTUs relate . I have a three ring gas burner . It would typically have little flames about 1/2” high . Anymore is too much heat for me .

But yes heat and coolant flow are a balancing act . It sounds like you had your heat about right . If it’s too high , you’ll smear tails all through . The fact you were able to clearly detect tails suggests that your still was operating right and held back the tails .

Surprised you had trouble with the heads heart transition although it can get a bit of getting used to .

I personally would have had trouble running such a low ABV beer but then I have perf plates not bubble caps

[Saltbush Bill]

My guess is that you had trouble picking the cuts because you've used as much heat as you have.
You had to use that much heat because you can't correct you water flow accurately enough.
I'll have a stab in the dark and say that you don't own a needle valve?
Am I right or wrong about that?
Once we know that for sure we can give better feedback.
As Yummy pointed out you need separate water feeds to dephlegmator and product condenser.
Regarding take off speed, that will vary to some degree depending on product and amount of plates used.

[drmiller100]

From a theory standpoint if you insist on not using a y run the water through the product condenser first. That way you can always have enough cooling in your product condenser.
The way you did it your heat could overwhelm the dephlqg heating the cooling water so the water is already too hot to condenseninnth product condenser. I agree a y and a needle vkve in dephlag feed would be better

[LWTCS]

The only way running your cooling media into the PC and discharging into RC actually works well is if your PC has enough surface area that it is completely unaffected by any adjustments to the RC.

At the hobby scale independent flow to each HX provides the widest operating range.

[JimBob88]

Thanks for all the reply's so far this is great! to answer some of the questions;

you are correct in that I am not using a needle valve in my RC, I am using a 1/2 inch ball valve (my RC intake is 1/2 inch pipe thread)

Ok good to know I will plumb it up with Y's for the next run. To be honest that was my original plan but i saw in a few posts and in a video or two where it was plumbed from PC to RC and I didn't have to buy any more hoses so I thought i would give it a try, lessoned learned.

I did not know that if you run it to hard you can push tails through the whole run, but it makes a ton of sense once you think of it. Thinking back on the run i think i was picking up on some through the run but i chocked it up to a brand new recipe i wasn't familiar with. That being said the turn from hearts to tails was like hitting a brick wall so i know i got some good stuff out as well. I have it sitting on oak now and if it does not trend in a good direction before my next run i will dump it all back in.

[Sporacle]

you are correct in that I am not using a needle valve in my RC, I am using a 1/2 inch ball valve (my RC intake is 1/2 inch pipe thread)

Just to show the difference between a needle valve and a ball valve.
My needle valve is 7 full turns between off and on.
1/4 of one turn changes my output by around one litre per hour.
I could not imagine trying to regulate a defleg with a ball valve.

[shadylane]

I am using a 1/2 inch ball valve (my RC intake is 1/2 inch pipe thread)

Depending on dephleg a 1/8 inch needle valve would be a better choice.

Ya might want to consider a shroud so the propane burner can heat the pot instead of the still house.

[Saltbush Bill]

you are correct in that I am not using a needle valve in my RC

Fix that problem and you will then be able to run your plated column as intended.
A reflux condenser is made to condence everything,
A dephlegmator is a partial condenser so requires much finer adjustment, hence the need for a needle valve.
A reflux condenser is in two states only normally......on or off.

[BrewinBrian44]

Another consideration in addition to a more precise needle valve is having a consistent inlet water flow and temperature. If these two things fluctuate a lot, you’ll have a hell of a time keeping the still in the sweet spot.

I had to ditch my defleg when I moved because my well water pressure fluctuates too much, even with a pressure regulator hooked up. I now use a VM head above the plates and it seems to work well for what I make.

[JimBob88]

Ok so I got my plumbing figured out, built 2 Y joints for intake and relief so that should be ok going forward.

Now needle valve. Like I said I have 1/2” pipe thread for my dephleg connections and I have an option to buy a 1/2” needle valve. Should I go with that or should I build myself a brass monster and step down from 1/2” to 1/4” or 1/8” to install a smaller needle valve?

My city water pressure is very good we are fortunate enough to have mountains around us so the head pressure keeps my water flow from the hose bib pretty stable. The only thing that really affects it is if the shower and the toilet go at the same time which is pretty well never when I’m running the still so I am confident in my water pressure.

[Sporacle]

Personally I would run with two valves, keep your ball valve and plumb your needle and ball valve in parallel.
That way you can set your needle for your run and have your ball valve full open to compress and load.
Shut your ball valve off and bingo your deflagameter is already pre set via the needle.
The actual flow through the deflagameter during a run is pretty minimal.
The plumbing in parallel allows for a cheaper needle valve and not having to remember exactly how many turns you require

[harold01]

put the needle valve on the hot side or the (out) so the deflag is always full of water

[BrewinBrian44]

put the needle valve on the hot side or the (out) so the deflag is always full of water

I know it's personal preference, but I preferred the opposite, even though the defleg isn't completely full.

Here's the logic: You get a smooth temperature gradient by having the cool water come into the top which in theory should improve performance. In most cases, it doesn't take much flow at all allow the defleg to knock down the vapor. My needle valve was almost fully off when I had things balanced. That lost volume of water was meaningless in my case.

[Sporacle]

And there in lies the question, water inlet top or bottom?
Just running mine now and there's definantly not a temp gradient.
I'm pretty sure it wouldn't make a great deal of difference which way it's plumbed as long as it doesn't siphon, in my case.

Constant pressure and temp however do make a difference, I have to open my valve a little more in summer due to the temp of water in the tank on the shed.

[drmiller100]

What is a 1/2 " needle valve?

If you don't have the coolant leave the top how do you get the air out?

[JimBob88]

Ok well I have ordered a 1/2" NPT needle valve which will be here next week. Hopefully between that and my new plumbing I can get everything dialed in and have a much more successful second run with this thing.

I never really even thought about valve positioning on the dephleg, that being said I do not really see how it would matter which side you regulate. I like the idea of valve/water in on bottom so that the whole thing is filled with water creating a stable gradient all the way through it and just pushing out the small metered amount once you tighten up your valve. The same effect would happen if you had valve on top and water straight in the bottom though. But at the end of the day if you get the results you want it does not really matter where it goes.

My real question on the matter would be why would you put your cold water in the top? keep in mind that my knowledge of thermal dynamics is what they taught in high school but hot water should naturally sit on top of cold water thus with cold water in the bottom would allow it to take its natural place pushing the slightly warm water up creating a stable temperature gradient. If cold water came in the top would it not upset that gradient by trying to sink past the hot water? I'm sure someone a lot smarter than I can explain where my thinking went wrong but that's how I see it

[LWTCS]

With respect to tube and shell heat exchangers, counter flow yeilds the best efficiency.

When we apply counter flow to the dephlegmator, based on minimal/easiest cooling circuitry we end up with an air bubble at the top of the dephlegmator. Basically the shell ends up being not completely filled with cooling media. This reduces efficiency.
This issue can be engineered out but adds a bit more complexity.
And since a dephlegmator does not necessarily rely on 100% optimization to do its primary function most of us introduce the cooling media from the bottom and exit the top to minimize the size of the bubble at the top of the shell.


Installing the flow control valve on the exit port prevents any unwanted syphoning. Some worry that installing the valve on the discharge side will pressurize the shell to the point of causing a leak. I find that concern absolutely easily preventable.

In either case its a choice one makes on how much you want to exploit efficiencies and which efficiency you will prioritize.

[Saltbush Bill]

This issue can be engineered out but adds a bit more complexity.

If you don't have the coolant leave the top how do you get the air out?

This is how I did it over 10 years ago, Ive done both ways, feed in the top and out the bottom on my 4 incher, Dephleg on my 6 inch runs in bottom out top.
Personally Ive not noticed a great difference between the two ways.
I suspect that if you were to make a super long dephlegmator, top in bottom out, may work noticeably better but Ive never done that to find out for sure.
I can say that trying to run in the top and out the bottom without some form of air bleed doesn't work well for me.
Photo below of air bleed off tap/ tube on my 4 inch plater.

air bleed valve.jpg

air bleed 4 incher.jpg

[Yummyrum]

Installing the flow control valve on the exit port prevents any unwanted syphoning. Some worry that installing the valve on the discharge side will pressurize the shell to the point of causing a leak. I find that concern absolutely easily preventable.

That has always been my thinking and way I’ve always done it …. On all my condensers .
I also believe that a well made condenser should have no problems handling water pressure .

However , there are stories from members that have had situations where the water in the deflag has got so hot and not been able to exit via the valve .
This has resulted in the boiling water now getting back to the feed hose causing it to melt and spray hit water everywhere .

Now I think in this case having a lower feed pressure would help …… and not letting a situation happen where the deflag water could boil ….. but shit does happen .

And I will continue to run my stills off a low but reasonable water pressure but control flow via the condenser outlet.


As a side note , I have seen Salty bleed the air from his top feed Deflag . It is a thing .

[drmiller100]

This issue can be engineered out but adds a bit more complexity.

If you don't have the coolant leave the top how do you get the air out?

This is how I did it over 10 years ago, Ive done both ways, feed in the top and out the bottom on my 4 incher, Dephleg on my 6 inch runs in bottom out top.
Personally Ive not noticed a great difference between the two ways.
I suspect that if you were to make a super long dephlegmator, top in bottom out, may work noticeably better but Ive never done that to find out for sure.
I can say that trying to run in the top and out the bottom without some form of air bleed doesn't work well for me.
Photo below of air bleed off tap/ tube on my 4 inch plater.
air bleed valve.jpg
air bleed 4 incher.jpg

That certainly works.

I admire your craftsmanship. You build things much better than I can.

[JimBob88]

[/quote]

That has always been my thinking and way I’ve always done it …. On all my condensers .
I also believe that a well made condenser should have no problems handling water pressure .

However , there are stories from members that have had situations where the water in the deflag has got so hot and not been able to exit via the valve .
This has resulted in the boiling water now getting back to the feed hose causing it to melt and spray hit water everywhere .

Now I think in this case having a lower feed pressure would help …… and not letting a situation happen where the deflag water could boil ….. but shit does happen .

And I will continue to run my stills off a low but reasonable water pressure but control flow via the condenser outlet.


As a side note , I have seen Salty bleed the air from his top feed Deflag . It is a thing .
[/quote]

Now see that is another aspect as to why I like water in the bottom with the valve so that there is no boiling water back flowing and melting cooling water in lines and that there is next to no possibility of pressurizing the condenser. Yes a properly built condenser should be able to handle the pressure in question but in my mind if I can avoid the need to cause pressurization why wouldn’t I? Seems like a fair trade for the possibility of some siphoning. But then again that is just a frozen Canuck's view of things. Seems like there is multiple ways to skin this cat and still make it home for dinner.

[Saltbush Bill]

I don't see how the water in a deflegmator is going to boil when the vapour going past it is always less than 100c....or at least should be if your running anything but pure water in the boiler.

[Yummyrum]

I don't see how the water in a deflegmator is going to boil when the vapour going past it is always less than 100c....or at least should be if your running anything but pure water in the boiler.

That is a fair point Salty and misleading . My apologies . I did say boiling . I should have said extremely frigg’n hot ….. enough to soften plastic hoses enough that the pressure caused them to rupture .

But this is most likely to occur when one shuts off cooling to strip out tails when vapour temp is up in the high 90’s