Otis’ Mini Boiler Build

[OtisT]

Otis’ Mini Boiler Build

I want to make a small volume boiler for a new still. The minimum volume in my 15.5 G boiler is 4 gallons and I need something else for running much smaller volumes.

Mini boiler build parts

Boiler Pan:
I picked up a cute little 10L keg today for my new project. I was considering using a 1/6 bbl keg which has the same diameter (same minimum volume level) but I like the lower height of the 10L keg for this new rig, thinking I would like to run this sitting on a counter. I may later regret limiting my max volume, but if I do I can always make another boiler in the future.

Element Attachment:
I have a small Dernord 500 W cartridge heater element that runs on 110V. The element is 1/2” MNPT threaded so I will use a 1.5” triclamp cap with 1/2” FNPT thread. I can weld the 1.5” ferrule low on the side for a minimum volume of about 3 liters. I also picked up a basic controller and small project box to put it in.

Column Attachment:
I’m not sure what I am going to do about the column attachment yet. I would like to stay simple and stick with the factory 2” ferrule on top. I’m considering adding a 4” ferrule on top so I can clean this easier. I know what a pain it is to clean out oils from a boiler that I can get my arm into, and am not sure how I would clean this w/o the larger opening. Maybe acid? I will likely go ahead and add the larger ferrule before I’m done. I’m still on the fence on this one.

The ferrule pictured is shorter than the one I will need if I go this route. I can pick up a taller 54mm ferrule that would put the lip even with the top rim of the keg.

Finishing Touches:
I plan to wrap the entire thing in insulation so I can get the most out of the 500 W element.

After this boiler is complete I hope to start work on a small copper head(s) for making gin, oil extraction, etc.

I’ll be posting more pics as I progress through the build.

Otis

[Chauncey]

Subscribed and awaiting more of the build.

Cool lil keg Otis!

[Single Malt Yinzer]

I was looking at making a boil kettle into a small still using draw latches. The reason I wanted to do a kettle was for ease of cleaning. https://www.amazon.com/uxcell-Stainless ... B07G1P72HK" onclick="window.open(this.href);return false;" rel="nofollow I figured it would look something like this: https://www.amazon.com/VEVOR-Distiller- ... 07DFH6WFV/" onclick="window.open(this.href);return false;" rel="nofollow Use flour seals around lid and it will be fine. A 2" column would be good. I think for a smaller still any larger and you're going to have to push a lot of heat into a small amount of wash.

Good luck on the build! Sub'ed in.

[Danespirit]

That will be a little cutie..
I would suggest leaving the opening unmolested.
As I don't know which oils you are referring to, I guess you mean if you've been running Gin or the like?
A vinegar solution will clean it all out again..no need for strong acids.

[OtisT]

That will be a little cutie..
I would suggest leaving the opening unmolested.
As I don't know which oils you are referring to, I guess you mean if you've been running Gin or the like?
A vinegar solution will clean it all out again..no need for strong acids.

Ya, I’m thinking primarily about oils from maceration and any reflux that may fall back down from vapor stripping in the gin head I am planning for this build. My design will have a collection cup and drain, but I’m sure at some point my cup will overflow.

I think I will start by leaving the top alone and only cutting it up if/when I find it’s not working for me. Thanks for the advice on vinegar. When cleaning I’ll start there and see where it goes. For macerations I figured I would cut up most solids that I macerate, and will use a wire hook for extracting solids through the side element port when done. Just a theory now, and I’ll see how that goes.

I’m sad today. I was all set to weld the side element this morning when I realized I did not have a 1.5” ferrule that was short enough to fit my TIG torch in. I got on-line and ordered what I needed, so I need to wait a few more days. I need a shorty because I can’t do a sanitary weld from inside the tank. To address this I will weld it like I do larger 6” and 8” column attach ferrules. I will weld the ferrule flush to the outside of the tank, inside the ferrule and outside, then grind out and polish the inside of the port. I need a short ferrule so I can fit my torch inside the ferrule for that inside weld.

Otis

[Oldvine Zin]

Funny coincidence that I started thinking about a mini just the other day. Definitely following your progress.

OVZ

[Danespirit]

You did the right thing....to wait for appropriate material.
You won't regret it once you see the end result. It will be smooth and clean. There is nothing like an ugly weld full of black oxidated material in it...
Regarding the macerations. Well, you could build a separate gin head with a drain on it. Nothing of the oils will ever touch the boiler.
Keep the pictures coming...

[OtisT]

You did the right thing....to wait for appropriate material.
You won't regret it once you see the end result. It will be smooth and clean. There is nothing like an ugly weld full of black oxidated material in it...
Regarding the macerations. Well, you could build a separate gin head with a drain on it. Nothing of the oils will ever touch the boiler.
Keep the pictures coming...

Thanks for the encouragement. I do plan to make gin head w/drain for this in addition to a simple pot head and mini liebig PC. When I get to that, it will likely be a whole new thread. Last night and today I designed what I want and I made a parts list. I’m very excited to get this done, especially the gin head, because I’ve not seen one like it on HD.

I’m new to making gin, but my understaning is that some things are better in the boiler, while others are better in the gin head. What do I know? I’m just a gin noob.

Otis

[NZChris]

You shouldn't need a drain, (or a sight glass), in a gin head as it should be able to finish the run without flooding. If it does flood, insulate it like they do at the Bombay Sapphire distillery. https://www.diffordsguide.com/producers ... stoke-mill

[OtisT]

You shouldn't need a drain, (or a sight glass), in a gin head as it should be able to finish the run without flooding. If it does flood, insulate it like they do at the Bombay Sapphire distillery. https://www.diffordsguide.com/producers ... stoke-mill

That’s great news, because the damn drain was going to be the toughest part to fabricate. So how much volume do you think the drain cup needs to hold? It will be fully insulated from boiler to the top of the gin head, so hopefully not to much.

I know this is a loaded question, but about how big should the basket be? Maybe reply in terms of basket size to product volume collected?

I was thinking of making a small unit, with a basket that is 3” round and 4” tall with some open space below where vapor enters and space above to ensure the vapor path remains clear. About how much product could you run through a basket like that before the botanicals are spent? I can easily make it taller or even go 4” round if recommended. I’ve not made gin before, so am not up to speed on the volume of botanicals I will use per volume.

Thanks. Otis

[NZChris]

If you intend running with everything in a basket, it needs to be big to keep the vapor speed nice and slow and to keep the pressure low. Mine is 8" diameter. Note that Bombay Sapphire runs their basket for ten hours. I run mine for six, compared to about an hour and a half when running with most botanicals in the boiler. Running for six hours is a PITA and the gin isn't fantastically better for it, so I don't do it very often.

If you are running with only the peels in the basket, which is how the majority of my gins are run, anything that doesn't hinder the vapor flow will do.

That said, I still sometimes run with everything in the boiler. It makes good gin. Just because some distilleries market that their fancy still is the reason you should buy their gin, doesn't mean you can't make something that you like even better using a simple pot.

[OtisT]

Thanks for the info Chris. I think the 3” will be fine for me then. I’m only running 500w, so that would be a vapor speed less than 4”/sec, which seems nice and slow. Otis

[OtisT]

A little update. I picked up the ferrule I needed and TIGed it on tonight.

First I tapered the back of the ferrule so the element will be horizontal. Used tape to mark the tapper for the initial grinding, then touched it up here and there to finish.

Tapering the ferrule

Welded the ferrule outside and inside. Put that sucker as low as I could get it. I’m still learning to fill, so my welds don’t look the best, but they don’t leak. I did a little grinding and sanding cleanup on the inside. Still more finish cleanup inside of the ferrule to go but I ran out of little 1” disk sanding drums. That’s as far as I got tonight.

Welded on ready for cleanup

Otis

[OtisT]

My mini boiler is all done. The final piece was putting the controller box together and adding some plugs. I did not have the correct plug for my element, so I used what I had on hand so I can do a cleaning run tonight. Next time I go to the hardware store I’ll swap that part out.

Controller box. I bought a 4000w 110V pre-made controller circuit for $14. I used both ends of a 110V extension cord for the power in and a socket for power out to the element plug. Threw it in a small project box with a few holes drilled into it for ventilation.

Simple 110v controller

I made a small riser arm with a brace for a little extra height and so that my little Liebig clears the boiler. The Liebig is 3/4”over 1/2” with a 14” vapor path. My local stainless parts store did not have a 2” ferrule cap with 1/2” threads, so I got a 3” cap with the threads to accept my riser. I already had the 2” to 3” reducer.

Completed mini boiler configured for pot stilling

Assuming everything runs well I’ll polish up the keg and call it done.

Otis

[OtisT]

Cleaning run complete and it runs great.

Some run stats
Takes 2.25 liters to cover element
3.5 liters at 28% ABV took 35 minutes to first drops (un-insulated)
Collection is at 55 minutes/liter at 500w with a few towels wrapped around the boiler
Mostly fast drops with occasional spurts/stream for a second
Liebig at .25 lpm was more than enough for really cold output

Conclusions
I definitely need to insulate the boiler
I may look at doubling the power by replacing the 500w element with a 1000 watt ULWD element.

Otis

[NZChris]

Takes 2.25 liters to cover element

There's not much in the way of convection current happening underneath an element, especially when there is something present to interfere with what little convection there is, like botanicals

My minis are heated from underneath to avoid that problem. I've never had a problem with burn on except for the time when I made a bad decision and ran the boiler dry.

[Oldvine Zin]

This is the element I purchased for my mini, it's a little pricey for what it is but for a 1000 W heater that I can fit into a 4" diameter tube I went for it, and at 240 VAC I can use my current controller
https://www.grainger.com/product/TEMPCO ... ater-4TCT1" onclick="window.open(this.href);return false;" rel="nofollow

OVZ

[OtisT]

That’s a cool little element OVZ, but I can’t use it. I want to stay 110V on my mini for simplicity and portability. This mini still is really portable and I like that I can run it on the kitchen counter, in the basement, other peoples houses, or else ware. My access to 220 at home is limited, and heavy wire and plugs are spendy. The 110 controller I put together for this mini is rated for 4000w, so all I need is to slap a cheep 110 plug on a new 110v/1kw element and I’m all set.

Otis

[OtisT]

Just a minor correction to a previous post on the stats for this boiler:

The minimum volume to cover the element is 1.75 liters. ( I previously listed it as 2.25l).

That small math change made a big difference in my recent gin run. With a 43% ABV wash of clean neutral with botanicals for a gin run, I needed 3.5 liters total minimum volume so that I could extract all of the alcohol and still have my element covered. It’s critical to be able to extract almost all alcohol in a gin run, as some of those root botanicals don’t come through until the very, very end of the run.

Otis

[NineInchNails]

I see you observed that the 500W element is too small. I would get a 1,500W 110V element if it can fit inside that little keg. More powerful the better.

I just ran some quick calcs and that 500W 120V element would bring 3 gal of 55F water to boil in 2 hrs.

1,500W 120V element would bring 3 gal of 55F water to boil in 41 min.

[OtisT]

Ya, I definately want a little more power. I didn’t mind the run speed at 500w but warmup was a tad bit slow. I was thinking of going up to just 1000 w, with a stick element, but those sticks are a bit spendy as compared to a 1500w loopback. Good thing I welded a ferrule to the keg and not a 1/2” threaded coupling. At least there I was thinking ahead.

My controller will handle an upgrade but I used a cheep extension cord and plug for the wiring, 13 amp max, so I will likely replace it with the next gauge up and a heavier plug end if I go 1500w

I was going to fabricate a SS screen over my stick element. Not sure what I will do now if I end up with a loopback model. Time for more thinkin.

Otis

[NZChris]

If all of the botanicals are in the basket a quick heatup is fine, but if they are in the boiler after an overnight steep, I'd question the desirability of a short heatup time.

[OtisT]

If all of the botanicals are in the basket a quick heatup is fine, but if they are in the boiler after an overnight steep, I'd question the desirability of a short heatup time.

Yes, I agree 100%. It all depends on what I am running in this boiler. Sometimes I will be able to use more power, and sometimes I will want to keep the power low, and sometimes I can use both in the same run. That’s the joy of using a controller.

I’m keeping the 500w element regardless (I already bought it.) and will likely finish the screen I had planned for it just because it looks like relatively little work. I will definitely get a more powerful element for when I need it. I’m outfitting my mini-rig for multiple purposes and I’ll need the range of power to have it do all I want it to.

Otis

[pope]

Otis! Is this the 1500w heater you're thinking of?

https://www.dernord.com/collections/hea ... nch-thread" onclick="window.open(this.href);return false;" rel="nofollow

[OtisT]

Otis! Is this the 1500w heater you're thinking of?

https://www.dernord.com/collections/hea ... nch-thread" onclick="window.open(this.href);return false;" rel="nofollow

I looked at that one and while it’s certainly a good profile I don’t think I would use it unless I can’t find something better for this application. The downside is that this element is a high watt density and while it would be great for clear spirits it could scorch a dirty wash or botanicals in the boiler. I have not found what I’m looking for yet, which would be a short low watt density element with a 1.5” ferrule attach. It’s not that I can’t find one, but rather I’ve just not looked for one yet, My 500 watt element is working for me until I have time to look for what I want.

I was considering using this one, and making a stainless screen to go around it. I may still go that route when I’m ready to upgrade.

Otis

[pope]

I could see that. I plan on only using low wines or neutral maceration's and straining anything that would go into a mini-build, it might be a good fit for me.

For a screen, you mean sort of like the 'bazooka screens' that are used in mash tuns by some beer brewers?

[OtisT]

I finally upgraded my element. Rather than buying a more powerful cartridge style element, I went with this 1500w fold back model with a built in 1.5” ferrule. Also more surface area.

1500w element, 1.5” ferrule

The more powerful cartridge style element used a 3/4” NPT attach, where my 500w model uses 1/2” NPT. I would have needed to buy another ferrule to FNPT adapter for $15, so the new style saved me some $.

Otis

[6 Row Joe]

My 3 gallon pot came with a 2000 watt element and I wanted to slow it down a bit so I picked up a 1400 watt water heater element and a adapter. It works great on a 15 amp circuit and heats up fairly fast.

[pope]

I am finally wrapping up my 5-gal build. I put a 4” ferrule on top so I can move my main column over (overkill? Yes), and got that 3/4 npt cartridge. I actually flipped the keg so the bottom has the original port that used to be the top. My plan is to also try using this as an aging reactor. I haven’t measured my minimum volume yet but it’s pretty small. Excited to be able to test little 2-3 gallon charges of low wines!

[OtisT]

Pope. Your gonna love it. I have been able to do a lot more distilling and have tried different things since making my mini. Stuff I would never have gotten to with my larger boilers. The mini is also great for repair runs and re-dos. It’s a great companion for my larger stills. After making a small gin head for it, it’s become my favorite still to work with.

Next week I will be helping a friend experiment making plum brandy from a large batch of wine she made. We will be doing a few strips with my 15.5 boiler then lots of small batches in my mini, playing with different amounts of passive reflux, 1.5 runs with different wine/low wine ratios, etc.

Otis