Internally jacketed direct injection for grained ferments

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fog
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Internally jacketed direct injection for grained ferments

Post by fog »

Hi all, I've just finished this still and I'm pretty pleased with how it functions, both as a steam generator for cooking corn in other vessels and sterilizing equipment but mainly for doing stripping runs for ferments on the grain or (I haven't done it yet) fruit. The idea is to have a steam generator built into the still for efficiency and compactness. The small volume of the steam generator is great for quick heating times (about 90 seconds at 220V)

Here is the general diagram:
Still diagram.jpg
1) Water boils in the internal horizontal part of the boiler,
2) steam rises up and separates from the boiling water in the vertical part of the boiler,
3) is forced into the steam escape and manifold, which is welded through the bottom of the boiler, and
4) enters the mash, releasing heat and stirring the mash around the boiler for better heat transfer.

Not pictured but also part of the boiler section is a water sensor and a freshwater injection port to maintain the correct water level. The whole thing is controlled by an Arduino which tracks the water sensor, three temperature sensors, and has outputs to control the heater and a solenoid for fresh water input. The Arduino can report back to computer every 6 seconds if you want to track data.

Here are some pictures of the actual build, let me know what I can improve!

And let me know what I should do as a vacuum breaker -The top 3/8NPT port on the end of the boiler where it comes out of the keg is for that, but as of now I just have a cap I have to remember to loosen when I shut the power off to the heater... Someday I'm going to forget that. I'm not too worried about overpressurizing, the silicone tube from the solinoid to the fresh water port is pretty loose and pops off if the pressure gets above 15psi (I've got the incoming water regulated down to 5psi.)
Body.jpg
This is the overview. Pressure cooker as top port and also as support for the column. It's annoying to have to dismantle the column to get into the body, but the extra height is better for the boiler.
Uncapped boiler.jpg
Here you can see the boiler -The horizontal part down inside and the vertical coming up to it's top plate and 2" port. Through that port you can see the top of the steam downtube.
Steam Cap.jpg
If I just want steam, I cork the downtube, and put this cap on the 2" port.
Capped for Use.jpg
In use as a still, the 2" port just gets capped and the ferment added from the top.
Inputs and outputs.jpg
This is the end of the boiler where it punches out the side of the keg. The heater is low, to best stay submerged. The water input is low, because I also use that to drain the boiler when not in use. The 1/2 pipe sticking out is the water sensor -it has a baffle in the boiler to reduce sloshing, and also the first 2" are packed with small copper wires for the same reason. The port at the top coming up at an angle should be a pressure relief/vacuum breaker -but I haven't figured that out yet -maybe just a pigtail as high as the wash?
fog
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Re: Internally jacketed direct injection for grained ferment

Post by fog »

Controller.jpg
Finally, this is the controller, which reads the resistance across the water sensor, three temp sensors, and turns the heater and water fill solenoid SSRs on and off. The heater can be switched between 120 and 240V and the duty cycle is variable with the pot, so I can get even heating over a range of wattages, from 0-4500W.
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shadylane
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Re: Internally jacketed direct injection for grained ferment

Post by shadylane »

I like it :thumbup:
fog
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Re: Internally jacketed direct injection for grained ferments

Post by fog »

I've done a handful of stripping runs with it and I'm quite pleased -you can dump 4500W into it without fear of scorching -Now I just need a better condenser to keep up!
fog
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Re: Internally jacketed direct injection for grained ferments

Post by fog »

As an update and cautionary tale, this setup has turned out very functional, but annoying to clean and cumbersome to use as a steam generator on it's own. As other people have suggested, it's nice to have a more modular system -so I've torn out the steam generator and built a new stripping still with more modularty.
fog
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Re: Internally jacketed direct injection for grained ferments

Post by fog »

Update to the update. I built a new bigger version using a stainless wine barrel and I LOVE it! I cook, cool, ferment, and distill in the barrel -so material handling is a breeze on larger batches. It's got a 2" ball valve, so when the processes are done, I drain it into a wheel barrow and feed the spent grain to the sheep.

Here's a couple pictures as I was building it, and then one of the business end -all set up. The little container holds a float valve which sets the water level, and the copper tube going connects to the top of the boiler, where it comes through the top of the barrel, and equalizes the pressure.
Big Still Top.jpg
Big Still Boiler.jpg
PXL_20211208_041110850.jpg
The top tube on the boiler is the fresh water input. Supplied by a solenoid which is controlled by the float valve. No electronic control, just electric.

The heater is there on the bottom. I have to pull it every time I want to flush the boiler. If I ever get my argon tank refilled, I'll add a drain on the bottom...

To the left of that is water out to the float tank, and a thermometer well, which I use if I'm running the heater on way low to keep a fermentation at a reasonable temperature.

For heat, I've got a 6.5kW element for which I can control the duty cycle and switch between 240V and 120V to get a range of reasonable power outputs. When I let the water run low and I burn this element out, I think I'll drop back to 5.5kW and accept the longer heat-up times.
Last edited by fog on Wed Dec 08, 2021 5:50 pm, edited 1 time in total.
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Kareltje
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Re: Internally jacketed direct injection for grained ferments

Post by Kareltje »

Very Nice!
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jonnys_spirit
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Re: Internally jacketed direct injection for grained ferments

Post by jonnys_spirit »

Wow that's pretty awesome!

Just interested in how the liquid level in the boiler progresses throughout a run with the water/steam condensing to a certain point in the mash. I guess the ABV in the mash reservoir reduces a bit faster than a gas or direct heating element approach since the evaporated ETOH reduces the ABV which is then replaced with water which further reduces the ABV... Not sure of the implications if any but just an observation.

Cheers!
-j
————
i prefer my mash shaken, not stirred
————
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Kareltje
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Re: Internally jacketed direct injection for grained ferments

Post by Kareltje »

Good question.
I see this system as a kind of internal boiler in a thumper. So its behaviour would be the same as a boiler with water and a thumper with pulp.
And also it would be possible to load the primary boiler chamber with a clean wash.

My question is: how do you bring the replenishment for the boiler chamber on the right temperature? I guess it is not wise to replenish with cold water/wash, for that would disturb the smooth run.
fog
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Re: Internally jacketed direct injection for grained ferments

Post by fog »

Jonny, you are correct that the steam injection dilutes the mash and more quickly reduces the ABV of the output. For the most part this is only a stripping still, so that's not as important. Overall, the liquid level in the vessel drops over a run despite the injection. I believe that this is because a fair amount of heat transfers through the boiler walls directly to the mash, and also that condensing steam imparts more energy than is required to boil the same volume of etoh

Kareltje, I don't preheat the boiler replenishment water. I have a needle valve on the input to slow down the replenishment so the boil never stops as the tap water comes in, but it must slow down the still just the same. Since it's primarily a stripping still, the fluctuation probably isn't as important?
fog
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Re: Internally jacketed direct injection for grained ferments

Post by fog »

The float switch has not triggered a couple times. I think over a 16 hour run run, scum builds up in the boiler, works it's way over to the float switch tank, and gums up the float. One of the times I wasn't paying enough attention and the boiler ran dry, burning up the element and ruining the batch. Anybody have suggestions for a more foolproof way to track water level?
fog
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Re: Internally jacketed direct injection for grained ferments

Post by fog »

I'm also interested in adding an agitator. My hope was that the steam injection right at the boiler would keep mash moving around it and facilitate heat transfer through the boiler walls, but with a thick mash that doesn't seem to happen and heat transfer throughout the still is slow. Anybody done a DIY agitator?
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shadylane
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Re: Internally jacketed direct injection for grained ferments

Post by shadylane »

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Re: Internally jacketed direct injection for grained ferments

Post by jonnys_spirit »

fog wrote: Wed Dec 08, 2021 6:16 pm The float switch has not triggered a couple times. I think over a 16 hour run run, scum builds up in the boiler, works it's way over to the float switch tank, and gums up the float. One of the times I wasn't paying enough attention and the boiler ran dry, burning up the element and ruining the batch. Anybody have suggestions for a more foolproof way to track water level?
Maybe a filter on the supply line would help keep it clean in the float tank? Or an electronic switch/sensor set at a certain depth that triggers with water present where you could connect it to a relay or SSR to open the valve?

Cheers,
J
————
i prefer my mash shaken, not stirred
————
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Kareltje
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Re: Internally jacketed direct injection for grained ferments

Post by Kareltje »

I like systems that do work correctly on their own, without regulators.
So why not use communicating vessels: on on the outside with fresh water and the other on the inside, being the boiler. Maybe with a kind of U-turn, to prevent hot water going to the outside tank? The level in the outside tank can be easily monitored and the flow inward will be just enough to keep the boiler at the right level and temperature.
fog
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Re: Internally jacketed direct injection for grained ferments

Post by fog »

Thanks for the link, Shady. I'll put some thought into that.

Kareltje, I've been trying to wrap my head around such a system, one which could be fed with the hot cooling water from the condenser, but I don't think it'll work. In use, the steam has to push against whatever head is generated by the level of the mash, which varies from run to run and over the course of a run. So the water supply has to be pressurized to overcome that.
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Demy
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Re: Internally jacketed direct injection for grained ferments

Post by Demy »

I like people who build and research innovations, I just wonder the advantage over a steam jacket ..
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shadylane
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Re: Internally jacketed direct injection for grained ferments

Post by shadylane »

Here's an external jacketed steam rig I built awhile back for comparison.
https://homedistiller.org/forum/viewtop ... 92&t=59138

On a side note.
Maybe Fog's build needs to be in the "Steam Mashing and Distilling" instead of being in the construction section.
fog
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Re: Internally jacketed direct injection for grained ferments

Post by fog »

@Demy, the advantages are:

1) buildability -I can weld, but I don't know much about forming or have a good way to cut and build jackets. This is just pipe and caps and fittings.
2) Energy efficiency -Heat generation is at the core, not at the outer surface
3) I was hoping steam injection would give me some mixing, and it probably does, though not enough in a thick mash. As a side note, I just ran a clean up run on a years heads and tails and with that purely liquid mash the heat transfer through the boiler shell was enough that it didn't use any boiler recharge until half way through the run.
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