Why can't I run a pot still by temperature ?

[Pikey]

On another thread [Edit - This thread about Urea http://homedistiller.org/forum/viewtopi ... 33&t=12896 ]

Oh dear, a couple of points here -

a) you cannot pot still a wash by temperature - it doesn't work like that.

huh? I just spent a day making 2.5 litres of ethanol , works fine what are you talking about?
.

You say your purity was guessed at 70-80 % and you say you distilled 2.5 litres of ethanol at a head temp between 78 and 82 ?

You were using turbo yeast and how much sugar in what size of wash ?

I presume you know you had got all the alcohol out because no more "stuff was coming out of the condenser - right ?

Yes I said that, unless someone knows a way test purity without the washes original specific gravity I cannot say for sure. Its jet fuel man seriously. I cannot keep the temps any tighter with the mantle I own, need one with digital temp probe.

immaterial, but if you must know 16kg in a roughly 60 litre tote, 20%abv turbo and about a cup of nutrient ( I figure it came out around 15% and I am distilling off about 10%)

No I did not get all the alcohol out, ran 1.5-2 litre batches and distilled about 200ml (+/- 20ml) off then cooled, siphoned, discard and reloaded. My mantle and boiling flask are only 2 litres so it takes some time and effort but am able to run it steady. Thermometer goes in one of these
http://www.ebay.com/itm/24-40-Glass-The ... 1519704116" onclick="window.open(this.href);return false;" rel="nofollow
at the top of this
http://www.ebay.com/itm/300mm-24-40-Vig ... 1028407221" onclick="window.open(this.href);return false;" rel="nofollow
stuck to one of these
http://www.ebay.com/itm/2000ml-24-40-Si ... 1277748409" onclick="window.open(this.href);return false;" rel="nofollow
the condenser is one of these
http://www.ebay.com/itm/410mm-24-40-Joi ... 2466721088" onclick="window.open(this.href);return false;" rel="nofollow

Does that help you explain to me why I "cannot" have achieved what I am standing here staring at? And why am I even having this conversation... it has zero to do with the my questions.

der wo has suggested we take this to another thread and the discussion may be of use to some other newbies too -

This thread is meant to be educational and is meant as an explanation thread, not a vehicle for belittling anyone.

Just finishing a run, back soon.

[miket]

I read the noobie stuff and it makes sense you can run a pot still with no thermometer at all. Too cold you got nothing, if its puking its too hot.

I touch the pipe coming out of the still and the pipe coming out of the thumper to tell me its getting ready to go. I use my finger to test the water around the worm to see its good and cold.

I'm still running it by temperature but I don't need a thermometer with a digital readout to tell me its hot.

[der wo]

For me it looks like a reflux still. So he can control the temperature.

[bluefish_dist]

I don't run a pot still often, usually just for shipping runs, but a thermometer in the head could give you approximate abv of the take off.
Personally I don't run a thermometer on the still head for stripping runs. I do use the thermometer in the cap of the still to tell when I have depleted all the alcohol. Once it hits 200 it's done. Note my boiling point for water is about 200 deg.

On a reflux still I do run it by temperature, but I can control the abv/temp with reflux ratio.

[Pikey]

Ok here I am back, good to see the thread moving

Here's a photo of my head thermometerat shut-down :

Head temp at shutdown - sorry about the quality !

If you stare closely you'll see 99.5 (C)

and here is a link to an approximation of what BurntEloi seems to have listed :

https://en.wikipedia.org/wiki/Fractiona ... aratus.svg


Now imagine that as a boiler, a packed copper column 40 " tall, without insulation and a head based thermometer which you used with a thermostat and power controller, to keep the head temperature below 82C - is that a pot still or a reflux ?

[Spritshere]

I read the noobie stuff and it makes sense you can run a pot still with no thermometer at all. Too cold you got nothing, if its puking its too hot.

I touch the pipe coming out of the still and the pipe coming out of the thumper to tell me its getting ready to go. I use my finger to test the water around the worm to see its good and cold.

I'm still running it by temperature but I don't need a thermometer with a digital readout to tell me its hot.

I find it very interesting that you can use temps to run your pot still. Now I have only run about 3 runs but I have found that several outside factors can effect how the still operates. Through all 3 of my runs I started getting product anywhere from 38C to 50C. So I just have stopped looking at it and running more by feel now.

[Pikey]

.......I find it very interesting that you can use temps to run your pot still. Now I have only run about 3 runs but I have found that several outside factors can effect how the still operates. Through all 3 of my runs I started getting product anywhere from 38C to 50C. So I just have stopped looking at it and running more by feel now.

You can't !

Where are you measuring that temperature and what with ?

[der wo]

is that a pot still or a reflux ?

It's a passive reflux still. Only controllable by heat input. The smaller the flame the more reflux you have. Of course the column heigth and the abv in the boiler limits the possible distillate abv, like always. And to get this maximum abv you have to run it extreme slow.

[Pikey]

BurntEloi, one of your questions was how do I measure abv of spirit without knowing original gravity - or something simeilar

You need an alcoholometer http://www.ebay.com/itm/0-100-ALCOHOL-H ... Sw7NNT~0IR

Not perfect but close enough for our purposes if you bear in mind the temperature has an effect.

[Spritshere]

.......I find it very interesting that you can use temps to run your pot still. Now I have only run about 3 runs but I have found that several outside factors can effect how the still operates. Through all 3 of my runs I started getting product anywhere from 38C to 50C. So I just have stopped looking at it and running more by feel now.

You can't !

Where are you measuring that temperature and what with ?

Those are column temps. I really only use it as a plug. Now I just run it by feel and sight. Use my senses to determine if I am running to slow or to fast.

[Pikey]

https://en.wikipedia.org/wiki/Fractiona ... aratus.svg


Now imagine that as a boiler, a packed copper column 40 " tall, without insulation and a head based thermometer which you used with a thermostat and power controller, to keep the head temperature below 82C - is that a pot still or a reflux ?

is that a pot still or a reflux ?

It's a passive reflux still. Only controllable by heat input. The smaller the flame the more reflux you have. Of course the column heigth and the abv in the boiler limits the possible distillate abv, like always. And to get this maximum abv you have to run it extreme slow.

Ok, so when I first started, I had exactly that - a column 1" in copper uninsulated but packed with stainless scrubbies and 1 metre (40") tall. If I held the head temperature at 85 C electronically (25 litre sour mash wash containing 5kg sugar fermented right out)

I got this :

There was no more to be had, however long it was maintained.

Removing the sctubbies and Letting the temperature rise indefinitely from the same recipe wash, (pot mode) I got this :

I find it hard to believe that that little glass tube with the teeth is anywhere near as efficient at creating reflux as a copper tube packed with scrubbies - simply because glass is such a poor conductor of heat and copper/stainless are so good !

[Edit - However, the abv whilst a little higher was not more than 80%-70% and clearly, there was a massive amount of good ethanol left in the boiler. ]

[Kareltje]

I read the noobie stuff and it makes sense you can run a pot still with no thermometer at all. Too cold you got nothing, if its puking its too hot.

I touch the pipe coming out of the still and the pipe coming out of the thumper to tell me its getting ready to go. I use my finger to test the water around the worm to see its good and cold.

I'm still running it by temperature but I don't need a thermometer with a digital readout to tell me its hot.

I find it very interesting that you can use temps to run your pot still. Now I have only run about 3 runs but I have found that several outside factors can effect how the still operates. Through all 3 of my runs I started getting product anywhere from 38C to 50C. So I just have stopped looking at it and running more by feel now.

I must assume that you mean 38 to 50 %ABV, not dgr C. Of course at 38 dgr C there is a bit of vapourizing, but not enough to get a measurable amount of distillate within a few days!
But I can agree with your observation that outside factors can influence the operation of the still.

Der Wo is clearly right: a Vigreux column is designed to cause a lot of (passive) reflux. When you run it very slow you could get a hot bottom and a cool top. I ran an iron column of 50 cm high slow enough to keep the top below 75 dgr C and than slowly heated up and pushed over the nasties in the heads. When I put some wet rags over my spiral riser I can do the same.
And to control it, you could very well use a thermometer.
But that clearly is not a pot still anymore!

[Kareltje]

I find it hard to believe that that little glass tube with the teeth is anywhere near as efficient at creating reflux as a copper tube packed with scrubbies - simply because glass is such a poor conductor of heat and copper/stainless are so good !

Remember: this glass tube is designed to do just that and the scale is much smaller than your metal still. And you can trun down the heat as low as you wish.
So what you lack in efficiency of the column, you can compensate by turning down the heating.

[Pikey]

I find it hard to believe that that little glass tube with the teeth is anywhere near as efficient at creating reflux as a copper tube packed with scrubbies - simply because glass is such a poor conductor of heat and copper/stainless are so good !

Remember: this glass tube is designed to do just that and the scale is much smaller than your metal still. And you can trun down the heat as low as you wish.
So what you lack in efficiency of the column, you can compensate by turning down the heating.

I could turn down my heating too. It never got more than that derisory amount of distillate - even with the head temp held at the higher 85C

A temperature gradient is a temperature gradient. It is dependent on the temp at one end, the temp at the other end and the rate of loss of heat. It is my contention that there is no way you can get the 100C neccessary in the pot, to get the alcohol out of the wash, without letting the head rise over 82C at the top of that glass tube. AT least not without applied cooling - I note your "Wet rags" - Remember also that the OP has taken "2.5 Litres ethanol" out of that setup in a day in increments of 200ml !

[Edit - to do that he must have been using it as a "Pot still" even if it doesn't look like one at first sight ! - either 12 or 13 runs in one day is hardly "running it slow" - however small your apparatus is

[heynonny]

In a word, yes, you can.

I have a thermo where the vapor 'goes over the top', besides feeling (for heat) the swans-neck for approaching vaper temp. I keep an eye on temp during distillation. Some 'purists' raise hogs & slaughter them, smoke their own bacon, etc. By this reasoning, one should only use a wood fired still, out in the woods. No electric, no propane, no thermometer. I go to the butcher counter for my meats, , , ,

-hey-

(bet I catch some flack for this'n!)

[Kareltje]

I find it hard to believe that that little glass tube with the teeth is anywhere near as efficient at creating reflux as a copper tube packed with scrubbies - simply because glass is such a poor conductor of heat and copper/stainless are so good !

Remember: this glass tube is designed to do just that and the scale is much smaller than your metal still. And you can trun down the heat as low as you wish.
So what you lack in efficiency of the column, you can compensate by turning down the heating.

I could turn down my heating too. It never got more than that derisory amount of distillate - even with the head temp held at the higher 85C

A temperature gradient is a temperature gradient. It is dependent on the temp at one end, the temp at the other end and the rate of loss of heat. It is my contention that there is no way you can get the 100C neccessary in the pot, to get the alcohol out of the wash, without letting the head rise over 82C at the top of that glass tube. AT least not without applied cooling - I note your "Wet rags" - Remember also that the OP has taken "2.5 Litres ethanol" out of that setup in a day in increments of 200ml !

[Edit - to do that he must have been using it as a "Pot still" even if it doesn't look like one at first sight ! - either 12 or 13 runs in one day is hardly "running it slow" - however small your apparatus is

I must admit: you have lost me. There are too much contradicting facts, or rather: statements, to take a stand.
One can run a pot still very slow to imitate a reflux column or run a reflux column very hard to get a pot still effect.

But I feel blurred about the orginal problem. Is there a problem to begin with?

The question in the head of this thread is simply answered: because of physical aspects of compounds.
You can not run a still by temperature. The temperature of the still runs you: it tells you what to do.

[shadylane]

My name is Shady and I run my pot-still by temperature
When stripping I set the temp controller to shut off at 98c

[Kareltje]

My name is Shady and I run my pot-still by temperature
When stripping I set the temp controller to shut off at 98c

[Pikey]

..........But I feel blurred about the orginal problem. Is there a problem to begin with?

The question in the head of this thread is simply answered: because of physical aspects of compounds.
You can not run a still by temperature. The temperature of the still runs you: it tells you what to do.

OP has put 16 kg sugar into a wash and has 2.5 litres "ethanol" (which I take to mean "Product" @ around 70-80%) - He seems to have run something arond 40% (6.4 kg sugar) of his original wash to do so.

He has done so by holding the head temperature on something approximating to a "Pot still with packing" down to a level which is imo a joke. Others say he has a reflux still - I say tell the geezer the truth !

[BurntEloi]

I have no idea what any of you people are talking about, this is a grade 10 chemistry set, I do not understand what everyone is debating. I am not here to debate whether my setup works, I know it works its lab equipment...anyway one last try.

original questions:

I checked the evaporation point for Ethyl Carbamate and it is 182 C so in theory even if I was producing ethyl carbamate it should be in the wastewater left over at the end of distillation, No?

Lastly is there a way to test distillates for Ethyl Carbamate or other common contaminants? Maybe a lab you can send a sample to?

[BurntEloi]

..........But I feel blurred about the orginal problem. Is there a problem to begin with?

The question in the head of this thread is simply answered: because of physical aspects of compounds.
You can not run a still by temperature. The temperature of the still runs you: it tells you what to do.

OP has put 16 kg sugar into a wash and has 2.5 litres "ethanol" (which I take to mean "Product" @ around 70-80%) - He seems to have run something arond 40% (6.4 kg sugar) of his original wash to do so.

He has done so by holding the head temperature on something approximating to a "Pot still with packing" down to a level which is imo a joke. Others say he has a reflux still - I say tell the geezer the truth !

Holy cow man, I have ONLY pulled 2.5 litres, I made way too much there is still like 40 litres in the container. Got to be another 6 litres of ethanol in there.
Everyone needs to stop making assumptions about my setup, totally irrelevant to the original questions. The apparatus is specifically designed to recapture solvents. Again I am not drinking this, the ethanol is for another purpose, I am only concerned with contaminants and purity testing.

[BurntEloi]

BurntEloi, one of your questions was how do I measure abv of spirit without knowing original gravity - or something simeilar

You need an alcoholometer http://www.ebay.com/itm/0-100-ALCOHOL-H ... Sw7NNT~0IR

Not perfect but close enough for our purposes if you bear in mind the temperature has an effect.

Thanks !
I have already ordered one from Aliexpress,
https://www.aliexpress.com/item/Alcohol ... 62161.html" onclick="window.open(this.href);return false;" rel="nofollow

Unfortunately it takes about a month for stuff to get here, I will definitely post back results when it arrives.

I found an article on a spoon test for moonshine, it burns blue, a little yellow towards the end (I assume thats residual water)
this was also interesting and informative
http://learntomoonshine.com/proofing-yo ... -explained" onclick="window.open(this.href);return false;" rel="nofollow

[Pikey]

I have no idea what any of you people are talking about, this is a grade 10 chemistry set, I do not understand what everyone is debating. I am not here to debate whether my setup works, I know it works its lab equipment...anyway one last try.

original questions:

I checked the evaporation point for Ethyl Carbamate and it is 182 C so in theory even if I was producing ethyl carbamate it should be in the wastewater left over at the end of distillation, No?

Lastly is there a way to test distillates for Ethyl Carbamate or other common contaminants? Maybe a lab you can send a sample to?

Ok let me try to explain why you don't have an answer to that question - The fact is that none of us can give you a definitive answer, because we just don't know for certain. We don't know enough about Urethane and its affinities for ethanol and water - but that could be a good thing - because if it was a sincere danger, the likelihood is that we would !

WHy should that be ? - for the same reason you can't run a pot still by temperature.

Ethanol boils around 78 C, water boils 100 C so heat the water up to 79 C and you can get all the ethanol and none of the water - No ?

NO !

Ethanol has an affinity with water and likes to be dilute. In fact you cannot by normal means get a pure ethanol liquid and if you could there wouldn't be much point because the minute you expose ethanol to the air it would pull water out of the air and dilute itself to 96%. This is called the "Azeotrope" and boils at a smewhat lower temperature than pure ethanol.

The boiling point of the ethanol / water mixture is on a sliding scale from "Azeotrope" at arond 75 C up to "Water" at 100 C it depends on the abv of the solution you are heating - Nothing else has much effect.

Here is a link to a diagram and explanation - look at the diagram - your wash at 15% should produce vapour at 65% abv which gradually drops as the wash abv drops and temperature has to rise.

http://homedistiller.org/forum/viewtopi ... 5#p6848109

Also note the title of the thread and you may wish to read the rest of it.

We do know rather a lot about distillation between us and your apparatus is quite interesting to us as it is unusual from our point of view. We have every desire to help you but in order for us to do so, you must learn a little about whet you are trying to do.

Now that diagram is for a simple pot still and we have methods of concentrating the alcohol by what we call Reflux stills - your apparatus is trying to be a reflux still. we would like to know how well it works - that's all.

Just out of interest, 16 kg of sugar fermented out, produces 8 kg carbon dioxide and 8 kg ethanol (near enough) - so your wash (if fermented right out) should contain a little more than 8 litres of PURE ethanol at 100% because the SG of ethanol is below 1 (which is the property that little hydrometer works on. If your wash is 60 Litres, the abv should be 15.7%

To get the alcohol out of the wash, the wash has to boil. you are holding the head temp down to 82 C which means low input power to give a temperature gradient up the column from the vapour temperature above the boilng wash to the 82 C at the head. In your apparatus this can only be achieved through natural heat loss through the glass. In fact it is worse than that because reflux relies on some of the water condensing out and running back into the boiler. This releases Latent heat of vaporisation, which again heats the system and has to be dispersed.

We generally use a water flow to take away this excess heat. You don't have any such mechanism - hence "Passive reflux" has been mentioned.

The problem is that if you hold your head temperature, all the heat inputs have to be released to the atmosphere, so the power you are allowed to use can only be very small - and the temperature of your wash cannot get up to the 100 C needed to release the last of the alcohol.

You can help us with this and perhaps get to understand a little better if you would ?

Next run you do, do it as normal. Then take away the container, place another there and turn up your heat a little - let the head temperature rise to say 90 C and let us know what results ?

It is a shame you don't have an alcoholometer, so to some extent we are flying blind - but hey - such is life.

[BurntEloi]

https://www.youtube.com/watch?v=0x2-8dedmE4" onclick="window.open(this.href);return false;" rel="nofollow
https://www.youtube.com/watch?v=TZo97aO4xbk" onclick="window.open(this.href);return false;" rel="nofollow

I can deal with "I dont know" , neither do I

I figured if anyone would know where to get ethanol tested it would be you guys. Carbamate is still a concern for me. This ethanol will be used in food oil extraction and any contaminants will get left behind in the extraction oils when the ethanol is removed. So I have to get a solid answer on this item. I will try some chemistry boards.

[BurntEloi]

I have no idea what any of you people are talking about, this is a grade 10 chemistry set, I do not understand what everyone is debating. I am not here to debate whether my setup works, I know it works its lab equipment...anyway one last try.

original questions:

I checked the evaporation point for Ethyl Carbamate and it is 182 C so in theory even if I was producing ethyl carbamate it should be in the wastewater left over at the end of distillation, No?

Lastly is there a way to test distillates for Ethyl Carbamate or other common contaminants? Maybe a lab you can send a sample to?

Ok let me try to explain why you don't have an answer to that question - The fact is that none of us can give you a definitive answer, because we just don't know for certain. We don't know enough about Urethane and its affinities for ethanol and water - but that could be a good thing - because if it was a sincere danger, the likelihood is that we would !

WHy should that be ? - for the same reason you can't run a pot still by temperature.

Ethanol boils around 78 C, water boils 100 C so heat the water up to 79 C and you can get all the ethanol and none of the water - No ?

NO !

Ethanol has an affinity with water and likes to be dilute. In fact you cannot by normal means get a pure ethanol liquid and if you could there wouldn't be much point because the minute you expose ethanol to the air it would pull water out of the air and dilute itself to 96%. This is called the "Azeotrope" and boils at a smewhat lower temperature than pure ethanol.

The boiling point of the ethanol / water mixture is on a sliding scale from "Azeotrope" at arond 75 C up to "Water" at 100 C it depends on the abv of the solution you are heating - Nothing else has much effect.

Here is a link to a diagram and explanation - look at the diagram - your wash at 15% should produce vapour at 65% abv which gradually drops as the wash abv drops and temperature has to rise.

http://homedistiller.org/forum/viewtopi ... 5#p6848109

Also note the title of the thread and you may wish to read the rest of it.

We do know rather a lot about distillation between us and your apparatus is quite interesting to us as it is unusual from our point of view. We have every desire to help you but in order for us to do so, you must learn a little about whet you are trying to do.

Now that diagram is for a simple pot still and we have methods of concentrating the alcohol by what we call Reflux stills - your apparatus is trying to be a reflux still. we would like to know how well it works - that's all.

Just out of interest, 16 kg of sugar fermented out, produces 8 kg carbon dioxide and 8 kg ethanol (near enough) - so your wash (if fermented right out) should contain a little more than 8 litres of PURE ethanol at 100% because the SG of ethanol is below 1 (which is the property that little hydrometer works on. If your wash is 60 Litres, the abv should be 15.7%

To get the alcohol out of the wash, the wash has to boil. you are holding the head temp down to 82 C which means low input power to give a temperature gradient up the column from the vapour temperature above the boilng wash to the 82 C at the head. In your apparatus this can only be achieved through natural heat loss through the glass. In fact it is worse than that because reflux relies on some of the water condensing out and running back into the boiler. This releases Latent heat of vaporisation, which again heats the system and has to be dispersed.

We generally use a water flow to take away this excess heat. You don't have any such mechanism - hence "Passive reflux" has been mentioned.

The problem is that if you hold your head temperature, all the heat inputs have to be released to the atmosphere, so the power you are allowed to use can only be very small - and the temperature of your wash cannot get up to the 100 C needed to release the last of the alcohol.

You can help us with this and perhaps get to understand a little better if you would ?

Next run you do, do it as normal. Then take away the container, place another there and turn up your heat a little - let the head temperature rise to say 90 C and let us know what results ?

Of course this thing is cooled, ice water in the reservoir is pumped through the condenser, its a standard lab setup.

I figured about the same abv for the wash and an azeotrope at about 92 deg C and kept it at around 79-82c for that reason. My mantle will not be any more accurate than about +-3 C. The boiler is running around 95-98c (if memory serves) at that head temp. If I crank it up I will just get more water. Speed of the distillation is heavily dependent on the condenser temp (that's just from my own observations, but seems pretty obvious).

I do not need to remove all the alcohol , this was an experiment in ethanol creation and distillation for use as a solvent. Secondary distillation will improve purity etc until I can get to approx 90%, then I will use 3a zeolite to dry it further before bottling. I am happy at 95%. Freezing the water out may also work to dry the ethanol, dunno. I am running the distillation in a way that I grab the easiest to get ethanol and just toss the rest in the wastewater. I have done this for energy and time efficiency reasons.

[HDNB]

wow! you can get to -170*? that's some cool (pun intended) lab stuff you got there.

[BurntEloi]

wow! you can get to -170*? that's some cool (pun intended) lab stuff you got there.

No idea what you are talking about

[HDNB]

wow! you can get to -170*? that's some cool (pun intended) lab stuff you got there.

No idea what you are talking about

Freezing the water out may also work to dry the ethanol, dunno.

about the temperature you would need to get to to freeze the water out.

[BurntEloi]

Ah, yes that is impractical then, I did say I didnt know, just a theory.

Maybe a salt out method would work, dunno
Zeolite definitely works and is reusable

[Pikey]

BurntEloi Any of our reflux stills can produce 90%+ spirit in a single pass - some considerably more.

Please come back when you have your spirit hydrometer, so we can talk further about how to improve your performance.

In the meanwhile, If cooler water through that Graham condenser of yours results in more distillate, the only logical reason for that can be that with warmer cooling water, not all the distillate is being condensed and some is passing through as gas. Please be aware this is a potential safety issue ethanol gas is highly inflammable and could explode. PLEASE run that condenser with very cold water !

Following my discussion with some of the others, If BurntEloi thinks he will need more than one pass to get up to 90% abv, as he does, I submit that his apparatus is performing more in line with a pot still than a reflux.

[Edit - I suppose you could say "Stripping runs then spirit run" - but in that case why hold the head temp to 82 C ?]