My first...Tea urn pot still

[sphaleron]

I wanted to share with you all my very first pot still….

Despite only just joining as a registered member I’ve actually been trawling these forums for over a year, carefully studying this amazing resource of information that has been so generously collected by the community. And finally after many months of study I have finished my first build….

My pot still is based on a Swan Tea Urn, similar to that shown by Ruminator (http://homedistiller.org/forum/viewtopi ... 16&t=32801). Here in the UK it seems stainless steel beer kegs are expensive and hard to come by. The Swan Tea Urn is something of a British institution frequently seen in churches, village halls and social clubs across the land. It is a 26 litre stainless steel boiler with a concealed 2200W element and thermostatically controlled. It also has a tap which will be handy for draining the waste product after a run.

We all understand that thermostatic control is no good for distilling so I have modified the tea urn’s internal electrics by bypassing the thermostat and providing an external homemade 3800W triac controller, complete with ammeter, giving me complete control over the full current range from zero to 10 amps.

A great feature of the urn is a boil-dry cutout switch which I decided to retain for safety.

The urn’s concealed element is not ideal from the point of view of maintenance and is unfortunately not replaceable so necessitates in the replacement of the whole urn if it breaks. However these urns can be picked up relatively cheaply on the second hand market and far less cost than that of a beer keg and paying a specialist who can TIG weld. Mine came up cheap due to a thermostat issue so was worth a punt.

The urn is quite tall so I decided to go with a narrow footprint vertical Leibig design with a 50cm 2’’ copper column rising vertically before turning 180 degrees into a 60cm long vertical condenser. The condenser output should be tall enough to place a tall beaker, jar, demijohn/carboy or even a parrot for collection of the distillate.

[still_stirrin]

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[sphaleron]

A large hole was cut out of the urn lid onto which a 30cm wide 5l stainless mixing bowl sits with a perfect interference fit. A small hole was cut into the base of the bowl and a threaded 2’’ tri-clamp ferrule fitted, secured on either side with 1 ½ BSP pickled brass nuts.

I have followed Somohon’s guide onto how to make everlasting PTFE gaskets (http://homedistiller.org/forum/viewtopic.php?t=24199). Firstly I made two 30cm diameter narrow ring gaskets, the first to sit between the tea urn body and lid, and the second to sit between the urn lid and bowl. With the addition of a double wrapped bungee cable the whole assembly is completely secure and 100% vapour sealed. The bungee hooks into the remnants of plastic handles that are conveniently riveted into the urn’s body. I also made three smaller gaskets, two to seal the threaded ferrule to the bowl and the final one to seal my column to the ferrule.

[sphaleron]

I followed Ct1870’s guide for making an Easy Flange (http://homedistiller.org/forum/viewtopi ... 0#p6824770) at the base of my column to couple it to the stainless steel ferrule. I tightly wrapped 4awg/5mm round copper wire around the base held in place with a jubilee clip and soldered. Filing and sanding it flat creates an amazing joint that couples perfectly to the 2’’ tri-clamp ferrule. The Somohon gasket sits between and forms a vapour tight seal.

The union between the column and the Leibig is a pickled brass 15mm equal compression tee to which I have fitted a ¼ npt threaded thermometer, not necessary as I understand for a pot still but a nice thing to have. This measures the vapour temp just before the start of the condenser.

Finally a good clean of the internals with a vinegar soak, vinegar steaming run and a polish of the externals with Autosol metal polish…Thanks to Kiwistiller for tips on cleaning (http://homedistiller.org/forum/viewtopic.php?t=15489).

I presently have a 23 litre batch of Birdwatchers TPW on the go which I’m gonna use for my sacrificial ethanol run.

I plan to use my still to make gin and rum. The tall column should be beneficial in providing space for a vapour infusion gin basket. I understand the pot still is not the best choice for making the initial neutral spirit and I am planning to build a Bokakob LM column and some point very soon

Any question or comments I would gratefully receive. Once again thanks to the community for such an amazing resource of information and I look forward to being much part of it going forward

[sphaleron]

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Thanks. Now corrected.

[As-Ol-Joe]

Nice job.

[thecroweater]

Nice job, as easy flanges are not a product that would suit our copper sizes here (Australia) so I'm not sure if seen (taken notice) of that post in your link but it is very similar to how I've done them before. You will be pretty limited to what you can do with the temperature information other than get a general idea of what the still is doing when. Just fall for that trick for new players thinking you can run a pot by temp or use them to indicate fractions.

[Danespirit]

Very nice job..!

I've only some minor changes I would have done...if it were my still.
I'm not keen on using brass in the vapor path of a still.
Especially not if one doesn't know the exact composition of it, as it is the case for a lot of brass used in plumbing and similar technical applications.
So I'd suggest to throw a couple of £ at someone on eBay and buy stainless steel lock nuts instead (without nylon rings). I use a similar type for my equipment.
It could be something like this: https://www.ebay.com/itm/1-1-2-Lock-Nut ... xyTMdTO56B" onclick="window.open(this.href);return false;" rel="nofollow
Also, change the tee at your thermometer which is also brass.
This kind of thermometer should fit a 1/4" thread, it's not hard to find similar made out of stainless on eBay.
I've also used this kind of rubber bands once...they work fine for the job and give/shrink with the temperature.

There is a groove cut into the lock nut...it will seal perfectly when you apply some PTFE tape. It will press firmly onto the surface and seal.

[The Baker]

I have two similar tea urns. Tried one and it didn't seem to heat enough (wouldn't boil water when nearly full). It has two elements so maybe one is not working properly, will check that.
I have a wooden cabinet about the right size that I am putting wheels on.

Geoff

[sphaleron]

I have two similar tea urns. Tried one and it didn't seem to heat enough (wouldn't boil water when nearly full). It has two elements so maybe one is not working properly, will check that.
I have a wooden cabinet about the right size that I am putting wheels on.

Geoff

These urns have two elements, one is the high power 2200W boiling element, the other the low power 200W "keep warm" element. Are you powering the low power one? I just have the high power one driven in mine and it has no problem heating 5 gallons of water to boiling point. Takes about 1 hour.

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[sphaleron]

Thanks for the advice everyone. Im not planning to use the thermo for any cuts, i intend to go by the old fasioned method of taste and smell. Regarding the brass: all brass fittings in the UK are certified for use with drinking water, so lead content must be very low. However in the presence of high proof ethanol more lead may leech out. I'll take your advice and look into SS alternatives.

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[The Baker]

I have two similar tea urns. Tried one and it didn't seem to heat enough (wouldn't boil water when nearly full). It has two elements so maybe one is not working properly, will check that.
I have a wooden cabinet about the right size that I am putting wheels on.

Geoff

These urns have two elements, one is the high power 2200W boiling element, the other the low power 200W "keep warm" element. Are you powering the low power one? I just have the high power one driven in mine and it has no problem heating 5 gallons of water to boiling point. Takes about 1 hour.

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Thanks, Sphaleron,

Yeah, I tried it on all three settings (low power element, high power element, both together). Interesting how long yours took, it gives me something to compare it with.
Both of mine are old, the electrician checked them for safety but the elements might not be heating properly...
They should be more efficient in the cabinet, away from coolness and breeze.

Geoff

[Still Life]

Good work, and spot on to the spirit of this site.

[sphaleron]

Good work, and spot on to the spirit of this site.

Nice pun

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[Still Life]

I was hoping you'd get that.
Make sure you do a proper clean when she's all done.
That's gonna make a fine performer!

[sphaleron]

Thanks, Sphaleron,

Yeah, I tried it on all three settings (low power element, high power element, both together). Interesting how long yours took, it gives me something to compare it with.
Both of mine are old, the electrician checked them for safety but the elements might not be heating properly...
They should be more efficient in the cabinet, away from coolness and breeze.

Geoff

If you have a multimeter test them for resistance. The high power one should be around 20 Ohm. If it reads significantly higher than that then it's broken unfortunately. The low power element should be around 200 Ohm.

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[thecroweater]

Modern plumbing brass is pretty much lead free, the safe level is really low and most are way below even that due to OH&S and litigation fears. Building a hole still out of brass would be risking it but one fitting provided you do a junkahol run is going to be of such a tiny risk as to be almost insignificant.

[sphaleron]

Ran my still for the first time as a sacrificial stripping run:

I charged the boiler with 23 litres of 10% ABV Birdwatchers TPW. It had started at SG 1.07, was regulated at 28degC, fermented out 7 days later at SG 0.99, and left out in the cold for 24 hours to settle. The yeast sediment has settled on the bottom making siphoning into the boiler easier.

The boiler was run at its maximum current of 10A. It took 45 minutes for the boiler to reach a temperature where I got the first drips of distillate from the condenser.

I kept the boiler running at 10A for the entire duration of the run and a steady dripping stream of distillate continued for the next 75 minutes. The thermometer showed ~90degC throughout. Between filling 250ml jars I collected 100ml samples to measure the ABV:

73%
65%
65%
63%
62%
58%
57%
55%
53%
50%
47%
44%
42%
39%
34%
28%
slowing
28%
24%
20%
stopped collecting here.

Towards the end the stream slowed. I stopped collecting at 20%. In total I collected 4.5 litres of low wines with a collective ABV of 45%. I made no cuts, not even foreshots. The low wines smell kinda fruity and very potent - not sure what to expect at this stage. The waste product left in the boiler smells like tomato soup!

Total time for stripping run from boiler on to boiler off = 2 hours.

Looking forward to getting started on the first batch I can eventually drink. More Birdwatchers is already fermenting

[zapata]

Something is wrong with your temp readings. Shoulda started producing somewhere around 80*C and slowly climbed to near 90* at the end. Unless thats what you meant by "~90 throughout"?
Otherwise sounds like it ran exactly as to be expected.

[sphaleron]

It was reading around 90*C throughout the entire duration of the run and appeared to increase by less than 5*C as the run progresed . I dont think the cheap chinese thermometer is particularly accurate. It was reading 110*C when i was doing my vinegar run and I'm guessing that's not correct either!

[Yummyrum]

Nice still you have made there . I'm still using a Samohon Everlasting gasket too....they last, mines over 5 yrs old

It was reading around 90*C throughout the entire duration of the run and appeared to increase by less than 5*C as the run progresed . I dont think the cheap chinese thermometer is particularly accurate. It was reading 110*C when i was doing my vinegar run and I'm guessing that's not correct either!

Time to boil some water ...that will sort it out ......but there are some here who will tell you to toss it anyway

[jb-texshine]

Ill say it. Toss the therm. It's obviously inaccurate and is unnecessary. At best it can only tell you the percent alcohol the vapor is. And that only if you have a temp chart handy to find the conversion.

[zapata]

DONT TOSS IT!
It's a perfect place to put a smiley face sticker or something.

[sphaleron]

DONT TOSS IT!
It's a perfect place to put a smiley face sticker or something.

Definitely!

[sphaleron]

Nice still you have made there . I'm still using a Samohon Everlasting gasket too....they last, mines over 5 yrs old :

Cheers. Good to know the Samohon gaskets last for so long

[sphaleron]

Ill say it. Toss the therm. It's obviously inaccurate and is unnecessary. At best it can only tell you the percent alcohol the vapor is. And that only if you have a temp chart handy to find the conversion.

After studying the vapour temp chart it seems that my vapour path thermometer is actually working well. I estimate my wash started at 10% Abv which corresponds to an initial boiling temp of 93*C and a vapour abv of 53%. I ran the still until the output and the vapour abv was 20% corresponding to a temperature of 98*C. So over the course of the stripping run the temp should have only risen by 5*C which agrees with my thermometer readings. Am i missing something? How do the other components of the wash contribute to the temperature evolution during the run?

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[zapata]

Maybe, something seems screwy though. Now I look back at your ABV, and they don't make sense. I don't know how you are getting such high abv from a 10% wash in a pot still. Saying your initial abv of 53% sounds right, but your first jar was 73%?
I tried running your parameters through the calculator on the parent site but can't get anything on a pot still to line up with your collected abv's...
Here's the closest I can get, I calculated your wash at 10.3% UK power is 230V, so 10 amps is 2300 watts, right?

Distillation by Pot still. We are using the below parameters:
Alcohol Content = 10.3 % (%ABV of wash/Low wines)
Volume of Wash = 23 L
Initial Temperature = 28 °C
Heat-up Power = 2300 W/h
Distillation Power = 2300
%Internal Reflux = 10 %
Main Run Time-steps = 10 minutes
Main Run Max-Time = 75 minutes
Tail Run Time-steps = 0 minutes
*** Main Run -- Heatup Time: 43 minutes ***

Time Boil Temp Vapor Temp Collected Purity Collected Purity
------ --------- ---------- --------- ------ --------- ------
10 min 94.14°C 83.18°C 884mL 47.6% 884mL 47.65%
20 min 94.96°C 83.78°C 844mL 43.3% 1.73 L 45.53%
30 min 95.72°C 84.50°C 806mL 38.8% 2.53 L 43.38%
40 min 96.42°C 85.36°C 770mL 34.1% 3.30 L 41.23%
50 min 97.05°C 86.39°C 738mL 29.6% 4.04 L 39.11%
60 min 97.60°C 87.59°C 710mL 25.2% 4.75 L 37.03%
70 min 98.08°C 88.93°C 685mL 21.0% 5.44 L 35.01%
75 min 98.29°C 89.63°C 334mL 18.2% 5.77 L 34.04%
*** NO tails run, by user request ***
*** Summary of Distillation ***
Starting: 23.00L @ 10.3% (2.37 L pure Ethanol)
Main Run: 5.77L @ 34.0% (1.96 L pure Ethanol)

In boiler: 17.23L @ 2.35% (405mL pure Ethanol)

Are you really getting enough reflux from that lid and riser to account for the discrepancy?
edit, I played with the reflux calculator just to see what it would take to approximate your results and can get close to your stated ABV by entering .5 meter of packing and just a 10% reflux rate, getting a final haul of 4.3 liters at 46%, the calculator says it would have taken twice as long though (but at just 10% reflux that doesn't make sense either, it would only be 10% longer, or my brain doesn't work any more)

[sphaleron]

Maybe, something seems screwy though. Now I look back at your ABV, and they don't make sense. I don't know how you are getting such high abv from a 10% wash in a pot still. Saying your initial abv of 53% sounds right, but your first jar was 73%?

Thanks Zapata,

I've run through the calculation myself and I'm also rather confused. Firstly why is the vapour temperature different from the boiler temperature? My understanding is that only happens in the presence of reflux when the equivalent of multiple distillations is occurring in the hypothetical plates of a column. In the absence of reflux the liquid and vapour temps should be the same? Certainly if I set the reflux% to 0% in the calc I still get a difference between boiler and vapour temperatures.

My initial starting ABV of 73% was definitely correct as measured by my alcometer. But I cannot replicate such a high ABV at all from a 10% wash, even with 99% reflux! So what is going on!? I am certainly not alone with this. Runinator reports similar performance for his/her tall column pot still (http://homedistiller.org/forum/viewtopi ... 16&t=32801). Could the other components (methanol, acetone etc) be contributing to this higher than expected ABV?

I am planning another stipping run this weekend so I'll keep diligent ABV and temperature readings throughout and report back.

I ran the calculation again with a reduced electrical power input to account for some heating inefficiencies. My stating temp was 10*C (it was a cold day!) and yes we are on ~245V here (rather high for UK standards). I get approximately the correct heat-up time and 20% ABV within the sensible running time.

Distillation by Pot still. We are using the below parameters:

Alcohol Content = 10.3 % (%ABV of wash/Low wines)
Volume of Wash = 23 L
Initial Temperature = 10 °C
Heat-up Power = 2150 W/h
Distillation Power = 2150
%Internal Reflux = 10 %
Main Run Time-steps = 5 minutes
Main Run Max-Time = 75 minutes
Tail Run Time-steps = 0 minutes

*** Main Run -- Heatup Time: 59 minutes ***

Ave Total Total
Time Boil Temp Vapor Temp Collected Purity Collected Purity
------ --------- ---------- --------- ------ --------- ------
5 min 93.70°C 82.90°C 418mL 48.7% 418mL 48.75%
10 min 94.09°C 83.14°C 409mL 46.8% 828mL 47.78%
15 min 94.48°C 83.41°C 401mL 44.7% 1.23 L 46.79%
20 min 94.86°C 83.70°C 392mL 42.7% 1.62 L 45.80%
25 min 95.22°C 84.01°C 384mL 40.6% 2.00 L 44.79%
30 min 95.58°C 84.35°C 375mL 38.4% 2.38 L 43.79%
35 min 95.92°C 84.72°C 367mL 36.3% 2.75 L 42.78%
40 min 96.25°C 85.13°C 360mL 34.1% 3.11 L 41.78%
45 min 96.56°C 85.57°C 353mL 32.0% 3.46 L 40.78%
50 min 96.86°C 86.04°C 346mL 29.8% 3.80 L 39.79%
55 min 97.14°C 86.56°C 339mL 27.7% 4.14 L 38.80%
60 min 97.40°C 87.11°C 333mL 25.7% 4.48 L 37.83%
65 min 97.64°C 87.69°C 327mL 23.7% 4.80 L 36.86%
70 min 97.87°C 88.30°C 322mL 21.8% 5.13 L 35.92%
75 min 98.09°C 88.94°C 317mL 19.9% 5.44 L 34.99%

*** NO tails run, by user request ***
*** Summary of Distillation ***

Starting: 23.00L @ 10.3% (2.37 L pure Ethanol)
Main Run: 5.44L @ 35.0% (1.90 L pure Ethanol)

In boiler: 17.56L @ 2.64% (464mL pure Ethanol)

[Pikey]

Maybe, something seems screwy though. Now I look back at your ABV, and they don't make sense. I don't know how you are getting such high abv from a 10% wash in a pot still. Saying your initial abv of 53% sounds right, but your first jar was 73%?

Thanks Zapata,

I've run through the calculation myself and I'm also rather confused. Firstly why is the vapour temperature different from the boiler temperature? My understanding is that only happens in the presence of reflux when the equivalent of multiple distillations is occurring in the hypothetical plates of a column. In the absence of reflux the liquid and vapour temps should be the same? Certainly if I set the reflux% to 0% in the calc I still get a difference between boiler and vapour temperatures.

My initial starting ABV of 73% was definitely correct as measured by my alcometer. But I cannot replicate such a high ABV at all from a 10% wash, even with 99% reflux! So what is going on!? I am certainly not alone with this. Runinator reports similar performance for his/her tall column pot still (http://homedistiller.org/forum/viewtopi ... 16&t=32801" onclick="window.open(this.href);return false;" rel="nofollow). Could the other components (methanol, acetone etc) be contributing to this higher than expected ABV?.............

[/quote]

Nothing wrong with your figures sphaleron = look at that column - you've got passive reflux going on and thus the head temp is higher than the boiler temp due to the latent heat of vaporisation being released. [Edit - Hell you've even rigged up an Alembic head for it ! (More passive reflux) ]

I have exactly the same still, except I use the original lid and a simple tank connector. I run a 1 metre column and get similar starting % ages to yours, but I run a little higher abv washes nowadays and my abv holds up a little better.

Mine starts producing at around 87 C and still has alcohol in at head temp of 103 C (sea level) - and yes my therms are accurate to a half degree or less.

Note to Geoff (The BAker) - You say your Electrician has "checked it over" - You need to bypass the internal thermostats mate - ese you'll never get it to boil ! (THe Electrician may or MAY NOT do this for you as they don't like bypassing safety features ) It's easy enough to do yoursef though, the connectors just push on and off !

[Edit 2 - Here's a pic of an old sour mash run I did years ago at similar abv to yours - Annoyingly I didn't measure the abv of the first jar - but it was likely 70% plus judging by the drop rate for the next few.

[The Baker]

Pikey said, 'Note to Geoff (The BAker) - You say your Electrician has "checked it over" - You need to bypass the internal thermostats mate - else you'll never get it to boil ! '

Thanks, Pikey.

These are the old style urns WITHOUT A THERMOSTAT.
Two switched elements. One greater capacity than the other.
Switch positions;
LOW (smaller element).
MEDIUM (larger element).
HIGH (both elements).

Geoff