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Feedback on our configuration

edited January 2019 in Configuration

Hi Guys!

First, great forum with a lot of valuable information and creative minds.

We are setting up our new pilot still right now and would appreciate any inputs and comments on our setup.

We will be running a 50-liter milk can boiler with a 4" Dash SG with three bubble sections and a gin basket. We have modified the milk can with 2 x 3 kw elements. All temperature probes and a can pressure gauge are all connected to our control system (Siemens Logo).

The temperature will be controlled by a PI regulator in the software. The power to the two heaters are controlled by SSR´s with PWM output from the controller.

The user interface is on a PC connected to the controller, where we also have the possibility to log all parameters and export to Excel for later analysis.

We will start with a simple temperature regulator setup. Over time the software will be developed with stuff like automatic
head, hearts and tails control.

Copper onion head is on the way and will be installed under the bubble sections.

Any input on the does and dont´s regarding the temperature control of the still will be greatly appreciated.






  • Gosh that's a really nice set up.

    With respect to temp control, what temps (where) are you specifically trying to control temps? You can control coolant temps and /or coolant flow rate to influence ABV. Don't waist your time trying to control your kettle temps.

    StillDragon North America - Your StillDragon® Distributor for North America

  • That cart is the bees knees.

  • edited January 2019

    Distill your gin's base spirit, making all cuts first. Then circle back and run that base spirit with no plates through the botanicals in your GB4. Two runs. Two still configurations. A distillation run, then an infusion run.

    I'm more like I am now than I was before.

  • Kapea plus one. All looks great but what the three plates for. Just put a straight section there. Nice looking elements. Not much temp control required to run that little beauty.

  • @Smaug said: Gosh that's a really nice set up.

    With respect to temp control, what temps (where) are you specifically trying to control temps? You can control coolant temps and /or coolant flow rate to influence ABV. Don't waist your time trying to control your kettle temps.

    Thank you all for your encouraging comments!

    We won´t waste a lot of time trying to control the kettle!

    @Smaug, beeing new to this i need to ask, the control of coolant temp/flow would that be in a dephlegmator or is this also an issue with the product condenser? Apart from minimizing water consumption of course.

  • edited January 2019

    I did not see that little dephleg there. Remove that as well along with the plates and your pc should only need a few l per min to make sure product is not hot. With the right combination of spools you should be able to put it back into plate mode keeping the heights right. To me the GB4 run should be as simple as possible with all the work done before the flavor run. Of course you could leave the dephleg there and just not use it or use it to change the botanicals basket but personally I don’t recommend that either as you just introduce more variables that make it harder to replicate.

  • No, we don´t have a Depleg there. Only the product condenser. Judging from all of your comments it seems that the GB run will be quite straightforward. This is encouraging!

  • N_D
    edited January 2019

    Hi Guys!

    Just an update on what we have made on our pilot still during the last couple of weeks. We have added a copper helmet. On the pictures all of the components are mounted. When we run the base spirit, the gin basket is removed. When we use the basket, the bubble sections are removed.

    We have also made a 10 liter tank for really small test batches. It will sit as a BM clamped between the 50 liter tank and it´s lid. The 50 liter tank will then be filled with water during the run.



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  • That's a good looking set-up

  • uh, that looks so tidy! Nice!

    StillDragon Europe - Your StillDragon® Distributor for Europe & the surrounding area

  • @Sunshine said: uh, that looks so tidy! Nice!

    Thanks! :-) It's a shame we "have" to remove the bubble sections for the gin run since it looks so pretty with them.

  • Dont remove the sections, just the plates. Then you have bling and functionality as well.

  • edited January 2019

    A reduced pipe fitting made to precisely fill the distance from your Alembic to your 2" would allow for an easy, rapid swap.

    Though your system is small and managable enough that plate removal is just not that much work compared to say,,, @CothermanDistilling's 30 plate outfit.

    StillDragon North America - Your StillDragon® Distributor for North America

  • yer gonna have to disassemble and clean after gin and before running non-gin, or customers of your non-gin products will not be happy...

    My suggestion? Just have two setups and make a nice document for each and print and put in a three ring binder.

  • N_D
    edited February 2019

    We are trying to add as many tools as possible to our pilot still, so we bought a 2" Big Baby Dephleg. We then started discussing automatic control of the water flow and found @CothermanDistilling post "Automating Reflux Condenser Water Flow". Since we have software PI controllers in the PLC with PWM output we will try to make a simple flow control valve from a standard ball valve and a model RC servo. The servo is controlled by a PWM signal. We only need to bring down the 24V signal from the PLC to 6V for the servo.

    The parts are produced right now in the 3D printer. If it works it will be a very low cost regulator valve.


    Dephleg control valve.jpg
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  • N_D
    edited February 2019

    It works! As a valve at least... On to the next step and hook it up to the PLC.

  • you bring the self building thing to the next level... ^:)^

    StillDragon Europe - Your StillDragon® Distributor for Europe & the surrounding area

  • edited February 2019

    For a small pilot still I’d use a pwm solenoid fed from tap water, via a regulator to keep the supply line very consistent - repeatable.

    Reflux valve sizing for small stills is really tough, especially with cool input water.

    Even the smallest Johnson valves can be too big.

  • As @grim said thats exactly what I found out. Smallest flow was still overwhelming the RC and/or PC even for the smallest adjustment. I’m pretty sure you can get it right eventually by pulsing it but I resorted to going back to manual as I was more focused on making stuff instead of trying tomake stuff work. For the RC, if running in parallel, I sometimes just run with a trickle, so you want to make sure that you can get down to that level.

  • Thank you! Thats really valuble input. We'll keep that in mind when we start testing.

  • Looks awesome!

    I would think that for the small setup here, a decent constant pressure regulator at 5-10psi would be the ticket for city water, and a small pump for using a cooling reservoir, with optional radiator before returning to reservoir.

    I do want to re-state that the temp probe for the controller needs to be inside the condenser... if you have it on the output, if it shuts, it will never re-open without some sort of bypass...

    Also think about possibly having a small pump constantly recirculating the water through the condenser and a good rate, and putting the valve on the hot side as an outlet, and have city or 2nd recirc water pump feed connected to the inlet..

    another possibility is a closed system (think cooling system of car) wide-open flow through a small radiator, and a PWM controlled fan on the radiator...

  • edited February 2019

    Rather than try to find inexpensive car radiators that don't leak, this is a slick solution.

    20x20 Water to Air Heat Exchanger Hot Water Coil Outdoor Wood Furnace @ Outdoor Furnace Supply

    Zymurgy Bob, a simple potstiller

    my book, Making Fine Spirits

  • I have 2 of the 24x24(200kbtu) ones and a 12x12(50kbtu)... but I bought the ones with enclosures and fans...

    The 50k one would be overkill for the baby, but is cheap on eBay. (FYI - both are cheaper on eBay form the same seller)

    the larger one can handle anything my 8" RC can throw at it, with no reservoir, because an RC does not need to get down to room temp... the other larger one takes the PC water down below 100F(in 80F ambient), where a glycol can take over if needed, but I just have it in a system with a 1000L IBC tote reservoir and if needed the next day, I just run it during heat up in the morning when the outside air is cool and it gets down to ambient in an hour or so...


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  • edited February 2019

    We just plumbed in a big Modine blower. Something like 200k btu.

    Only problem is that most of our plumbing uses constant flow/bypass plumbing, so none of the recirc feeds really get all that hot. I'll say it works pretty marginally. Doesn't really do much until the end of the run, when our recirc tank starts to really warm up.

    Usually, the indoor temps first thing in the morning in our place are about 50-55 degrees, so we were hoping to get some free heating. We'd really need to replumb to run the PC first, then feed the RC, than take the hottest RC feed into the blower.

    We run the chillers overnight, which helps a bit to warm things up, but the chillers are really kicking our electrical bill's as%.

    Otherwise, next step is a big dry cooler on the roof. Seems silly to not take advantage of the cold air.

  • yes, modine style are really dependent on delta-T, so will work great on RC that has 150+ degree water output, and PC running full flow... but even then, slower, hotter water is what he modine is most efficient on since it is not 'counter-flow'... That being said, I throw some serious heat on the neighbors parking lot ;-)

    The RC can work like a automotive system, the RC is the engine, the modine is the radiator, and your controlled valve is the thermostat. No real reservoir required, just a small tank or standpipe for expansion

  • N_D
    edited February 2019

    A big thank you for all the comments! I´m almost in information overflow mode. As we are newbies please bear with us with some questions that might be obvious:

    • @CothermanDistilling, "Placing the temp probe inside the condenser" will probably save us many hours of frustration, but it just struck me, do you regulate against the vapor temperature or against the water temperature?

    • @ all of you, why do you use a closed system with a heat exchanger/blower combo for the cooling water? Is it for easier control of the cooling or is it to save on city water costs? I ask because the cost of our water is more or less negligeble even for a large still. The only drawback is that the water is very cold in winter and not so cold in summer.

  • we regulate the water temp... see Automating Reflux Condenser Water Flow

    a closed system saves water... also, an RC is easier to control with warm water going in... and there is less chance of sub-cooling, that is, refluxing water that is way below the boiling point going back down the column... it just wastes energy and slows the still down imagine throwing ice cubes in your still....

  • edited February 2019

    @N_D said: Placing the temp probe inside the condenser" will probably save us many hours of frustration, but it just struck me, do you regulate against the vapor temperature or against the water temperature?

    Controlling for vapor temperature is difficult. It is absolutely possible, but it requires some fairly complex control capability, because traditional PID does not respond well in situations where there is variable dead-time.

    The major issue is the period of time in which you change the condenser flow rate, and that not only impacting the vapor temperature, but how long it will take for the column to reach equilibrium at the new temperature (proof/vapor temperature stabilize at the new level).

    Imagine if you were driving a car, and you didn't actually know how much time it would take for the car to turn, after you turned the steering wheel. It could be 1 second, it could be 10 seconds. Could you figure out how to drive?

    In systems with perfectly fixed dead time, and very responsive feedback, you can use a slightly more advanced PID to account for it. However, dead time is not at all fixed. Dead time at lower proofs is shorter than higher proofs (lower temperatures). Small columns are quicker than large, tall columns.

    Play around, maybe you can figure it out.

    Another option is running the reflux condenser at 100% and using valves to specifically control the reflux ratio that the column sees. Control the proportioning of the reflux/distillate.

    In this case, you can use a PID to manage the condensate temperature, which is slightly easier as the responsiveness is instantaneous.

    Controlling your reflux ratio could be done via table, no pid control. If you know the pot ABV start and end, the typical column operation, you can build a table of reflux ratio to time. For example, run 40 minutes at 100% reflux, then take off heads at 20:1 reflux ratio, then move to 10:1 reflux for hearts, moving back to 20:1 as you approach tails (keep proof constant).

    While this is more complex of a physical system, I feel the control methodology is far simpler, as you are decoupling the condensation and reflux ratio into two separate systems. I suspect this is how the iStill control model works, since it looks like a traditional LM design with automation on top.

  • edited February 2019

    In the LM (Istill) system, you don't control the RC and PC temperatures. Instead you rather control ketle temperature around setpoints of the process and at the same time are actively monitoring packed column temperature stability (base temperature below packing and immediately above packing) which in turn are interacting with reflux which is further determined by the distilling programme / type selected.

    What is important is that the RC must collapse all rising hot vapour such that nothing (hot vapour) exits out above it. For this the RC is super big. In my system, I am monitoring this top exit temperature as well as exiting water from the RC. Again all interlocked into an alarm / safety system.


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  • edited February 2019


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