Question about large head space when distilling small batches.

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sbnas
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Question about large head space when distilling small batches.

Post by sbnas »

My pot still is a 50L keg with a 600mm, copper packed, 2" stainless tube leading to some elbow joins where I have a 450mm shotgun condenser.

I have a 2000W element inside which heats fine but I need 13L minimum to cover the element which is fine for stripping runs. I wanted to be able to run smaller spirit runs so I mounted an old 2000W kettle element to the exterior base of the still in the hopes I can use that to heat spirit runs of only a few litres of 40%.

I have almost finished the mounting but was wondering on how well its going to work given the huge amount of head space in the still if I only have 5L in there when it can normally hold ~40L?

Is it going to run too slow? Will I get no distillate because there will be such a large area able to cause reflux? Or is it something i just need to try and see if it works?

I will likely remove the 600mm tube and replace with copper packing inside some T sections to reduce some of the head space available but I am still concerned about how much there will be.

Would love some advice from anyone who has done anything similar or who might see some issues in the design.
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Salt Must Flow
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Re: Question about large head space when distilling small batches.

Post by Salt Must Flow »

Can you post a pic of this "2000W kettle element" so we know what you're talking about?

Will this be a simple pot still spirit run?

For such small runs, I bought a 4 gal stainless pot with lid. I modified it for similar small runs because like you, it takes at least a few gallons to cover the element on my keg boilers.
sbnas
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Re: Question about large head space when distilling small batches.

Post by sbnas »

The element is similar to this.

It's basically a heating element moulded inside an aluminium block. I have mounted the block to the base of the keg so that I get as much surface area contact as possible and will be adding some galvanised sheet to act as a reflective shielding. Only one element will be used at a time depending on whether I am doing stripping or spirit runs but if the new one works well enough I may remove the old one and repurpose the hole as a drain point.

My runs will be normal pot still runs, I am not trying to get any level of reflux with the packing, its merely just there to have contact with copper.

I had considered buying a small keg and mounting an element to that but figured I would go for the zero cost option first and try to reuse what I had.
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Salt Must Flow
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Re: Question about large head space when distilling small batches.

Post by Salt Must Flow »

sbnas wrote: Thu Jun 30, 2022 6:29 pm The element is similar to this.
I had considered buying a small keg and mounting an element to that but figured I would go for the zero cost option first and try to reuse what I had.
I bought a 7.5 gal pony keg thinking the exact same thing you are, but it turns out ... it takes EXACTLY the same amount of gallons to cover the element in a smaller keg. So I highly modified that small keg for no reason and learned the hard way. Now I just use it for proofing and I use the bottom drain for filling gallon jugs. A small boiler is what you need if you want to do very small runs. It's a cheap solution and you can even run it on 120V. You don't need a 240V element for such a small boiler.

I've never used that kind of element you're looking at. I've only used ULWD (ultra low watt density) internal elements so I have no input on that element.
The Baker
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Re: Question about large head space when distilling small batches.

Post by The Baker »

it takes EXACTLY the same amount of gallons to cover the element in a smaller keg.

Unless you mount it lower!

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sbnas
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Re: Question about large head space when distilling small batches.

Post by sbnas »

Salt Must Flow wrote: Thu Jun 30, 2022 7:10 pm
sbnas wrote: Thu Jun 30, 2022 6:29 pm The element is similar to this.
I had considered buying a small keg and mounting an element to that but figured I would go for the zero cost option first and try to reuse what I had.
it takes EXACTLY the same amount of gallons to cover the element in a smaller keg.
The new element is mounted externally to the base of the keg so that the keg is heated through conduction which transfers to the wash. As opposed to the heat being direct from the element in contact with the wash sever inches above the base. I should be able to heat volumes as low as 2L, head room is all I am concerned about.
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Yummyrum
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Re: Question about large head space when distilling small batches.

Post by Yummyrum »

You'll be fine with the head space .
I’ve seen some folk use onions nearly as big as their boiler .
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NZChris
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Re: Question about large head space when distilling small batches.

Post by NZChris »

I've done spirit runs down to about 4l in a 33l still and they worked out fine. That said, I have accumulated smaller stills since then and won't have to do that again. Having a pot still the next size down that can do a spirit run from a single strip comes in handy when doing small experiments or using rare, or expensive, ingredients.
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Saltbush Bill
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Re: Question about large head space when distilling small batches.

Post by Saltbush Bill »

If you were not running a short arse condenser like a shotgun Id suggest that you used gas.
The beauty of using gas /LPG is that there is no limit to how small the wash can be.
Any small gas ring / camp stove would have a 5L wash up to operational temp in no time.
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EricTheRed
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Re: Question about large head space when distilling small batches.

Post by EricTheRed »

Saltbush Bill wrote: Thu Jun 30, 2022 11:29 pm If you were not running a short arse condenser like a shotgun Id suggest that you used gas.
The beauty of using gas /LPG is that there is no limit to how small the wash can be.
Any small gas ring / camp stove would have a 5L wash up to operational temp in no time.
Exactly what i do with my 5L - electric on the 30L and gas on the baby - even a 1 L wash works well

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Demy
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Re: Question about large head space when distilling small batches.

Post by Demy »

It will work, it will take longer to heat up because it is indirect heat and has to heat the entire boiler before it has output. I often run small batches, use a hotplate and a small boiler, if you do small batches often you could build one, it takes minimal expense.
sbnas
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Re: Question about large head space when distilling small batches.

Post by sbnas »

Demy wrote: Fri Jul 01, 2022 2:08 am It will work, it will take longer to heat up because it is indirect heat and has to heat the entire boiler before it has output. I often run small batches, use a hotplate and a small boiler, if you do small batches often you could build one, it takes minimal expense.
I had some electrical issues with the element I mounted so went away from that idea entirely. I am going to try what is probably a silly idea and mount a 500W element at the base of my 2" column removing the large keg entirely. Should let me do batches of about 1L at a time which will be ok, provided it works. I am trying to take the 'least cost' approach.
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NZChris
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Re: Question about large head space when distilling small batches.

Post by NZChris »

You may be misusing the term, 'column'. Pot stills have a 'riser' to raise the condenser outlet to a convenient height.

I have done batches of less than 1l in a saucepan with a steamer for a gin basket, but I don't think that is what you are describing. 'Use what you've got' is my way of thinking.

BTW, I often run 500W and less for gin.
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Demy
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Re: Question about large head space when distilling small batches.

Post by Demy »

20210718_103856.jpg
This is a small boiler that I built for such things .... in reality I have an even smaller one. Just a little inventiveness ... it's not beautiful but it works.
CuriosityKilt
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Re: Question about large head space when distilling small batches.

Post by CuriosityKilt »

My 2 suggestions:

1) Just get a stainless steel container ~10L and save up till you fill it and have another stripping run for a total of 15L.
2) Dilute your wash with filtered water and run.

Or do both.
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