Copper in the decending path

[DAD300]

Copper interacts with ethanol to make Ethyl Carbamate (urethane) on the descending side..

Well, the "Big Boys" sell fores and heads without batting an eye!

New Arnold Markdorf Hostein stills from Germany

For every old still with a copper condenser, I can show you a new one with SS Condenser.

At least see it as another chance to be BETTER than the commercial distilleries.

I'm not telling anyone to throw away their copper over copper leibig. But I'll show you how to build a SS one easier and cheaper.

Willing to accept copper in the descending path? But not a plastic funnel or a silicone gasket? Hmmm...

[thecroweater]

DAD300 wrote
Copper interacts with ethanol to make Ethyl Carbamate (urethane) on the descending side..

Reallly, copper does? i thought it was heating a solution containing urea nitrate and ethyl alcohol
http://en.wikipedia.org/wiki/Ethyl_carbamate" onclick="window.open(this.href);return false;" rel="nofollow
As stated In my post two posts back if there is enough copper in the ascending path then its likely its safe to use an inert material for some or all of the descending path but this would need to be tested and carefully calculated, very sure Holstein would have done that as it seems by their write up on the subject they take urethane production serious

[Odin]

Those big pots run almost continuously, giving copper rust formation almost no chance ...

Odin.

[humbledore]

I love it when Dad stirs stuff up. The mention of EC in the article states that copper salts collected on the downside can be a catalyst for further EC formation while the spirit is aging. In spite of a number of interesting graphs regarding DMTS there is no further mention of any study showing how great the impact is. Going from some of the footnotes, I found a couple of the sources had some interesting points.

The second or low wines distillation apparently eliminates
the time-dependent factor and ethyl carbamate formation
proceeds as soon as sufficient heat is applied to the still.
Fortuitously ethyl carbamate, once formed, does not readily
distil when the alcohol concentration is high. This means that
only small proportion, approximately 1-2 per cent of the
total available ethyl carbamate, will distil over during
collection of potable spirit. As the alcohol strength drops
from 64 per cent v/v to about 1.5 per cent v/v, further 15 per
cent of the available ethyl carbamate will be collected with
the feints. Gearly, the elimination of 84 per cent of the total
available ethyl carbamate with the spent lees prevents
substantial accumulation in the feints. This is significant
feature of the current work, since the practice within the pot
still whisky industry is to recycle the feints.

http://onlinelibrary.wiley.com/doi/10.1 ... 4618.x/pdf" onclick="window.open(this.href);return false;" rel="nofollow

and

The results obtained in the present study point out that double
distillation significantly reduces the content of ethyl carbamate
in sugar cane spirit. During the second distillation, around
97% of the formed ethyl carbamate was eliminated from
the beverage.

http://onlinelibrary.wiley.com/doi/10.1002/jib.14/pdf" onclick="window.open(this.href);return false;" rel="nofollow

In both cases these were all copper pot stills. Copper on the downside. Yet most of the EC already in the wash stayed in the wash. What I would like to see is, even after the second distillation, does further EC form while the spirit matures based on copper or stainless on the downside.

[humbledore]

And an interesting graph is in that second link showing that EC and copper residue in the distillate increases as the purity of the distillate decreases. I wish I could paste it here. The PDF is only a few pages long, it's worth looking at. Basically for the majority of the hearts the EC and copper coming over is very low. Then with the tails it starts increasing, potentially taking up to 15% of the total EC in the low wines. 85% stays in the pot. Makes you wonder about recycling tails leading to concentration of EC.

I am not jumping to any conclusions here I just like this kind of discussion and found this interesting.

[DAD300]

Odin, not just dirty copper, also clean copper.

humbledore, your answer... "Adversely copper salts in the new make does catalyses the EC formation during the maturation, so most grain distillers use only stainless steel in the condensers to diminish the amount of copper residues in the new make."

I usually don't like what I refer to as Lab Rat Discussions. That's why I started out as copper in the Ascending Path Good, Descending Path BAD!

Hot vapor or liquid reacts with copper to form EC.

The other articles weren't so cryptic.

"But copper in the takeoff and product condenser (vapor to liquid phase) adds a carcinogenic back to clean distillate. Ethyl Carbamate...caused by the high ABV ethanol reacting with copper."
-------------------------------------------------
"Double distillation will significantly reduce EC, slower distillation (more gentle heating) will reduce EC, using low EC-precursor malts will reduce EC, taking the pits out of Fruit will reduce EC, "stainless down" will reduce EC. There has been some discussion that higher reflux ratios will reduce EC in systems that use "stainless down".
-------------------------------------------------------------------------
"Elevation of natural ethyl carbamate levels, subsequent to distillation, only occurred if the distillation was carried out in the presence of copper. When fermented worts were distilled in all-glass distillation apparatus there was no significant ethyl carbamate formation.
------------------------------------------------------------------------------
This work demonstrates that not only is copper essential for ethyl carbamate formation, but that the mechanism of formation is dependent upon hot copper contact with some precursor which is apparently present in the vapour phase of the process."
-------------------------------------------------------------------------------------

These are quotes from many articles, some from a library I won't post links to.

Oh well it's out there now...that library has ten articles on EC.

[thecroweater]

Really ? so copper is the cause not the cure ? maybe re-read your very first link that you posted here or for your convenience here is an exert

Ethyl carbamate (EC, urethane) was a hot topic in the 1980s, as it was found to be carcinogenic and to increase during maturation phase of spirits. At the time various whiskies, especially grain or bourbon whiskies from stainless steel column stills were producing spirits with way too much EC and the concentrations seemed only to increase during maturation. It was found that copper in the ascending phase on still decreased EC dramatically and copper was (re)introduced into column stills. Adversely copper salts in the new make does catalyse the EC formation during the maturation, so most grain distillers use only stainless steel in the condensers to dimish the amount of copper residues in the new make.

The most influential part of distillation in terms of sulphur (DMTS) removal is in the spirit still body and interestingly in the vapour phase of the wash still, but not as much in the wash still body or the spirit still vapour phase. Alcohol concentration might play a role in the catalyst properties of copper. The spirit still condensers at the end of the second distillation have the least effect to the DMTS removal, on the other hand (at least in the column stills) the late phase condensers are shown to be important in conversion of dimethyl sulphide (DMS) to less aromatic sulphide.

[googe]

Does that mean copper catalyzes are no good?.

[humbledore]

We don't do continous distilling. So there's a finite amount of urea and cyanide for the copper to catalyze. After the first and second distillation (in which most of the EC is left in the pot) how much more do you think is left to catalyze?

That's all the science I have in me, I hated chemistry.

[MitchyBourbon]

Glad I read your post dad. I love the science end of our hobby.

Am I correct in concluding that to minimize EC I should have a copper column and a stainless liebig? Running slow, heating gently and not re-using feints also reduce EC?

What say you? Dad, thecroweater?

[thecroweater]

well it would seem that Holsteins think they are necessary

Copper Catalyzer
A patent we pride ourselves on – and rightly so.
Made of the purest copper that effectively binds cyanides and ethyl carbamates due to our lamella technology and the resultant surface expansion, thus permanently guaranteeing adherence to the stipulated limits.
The integrated bypass allows optional distillation without using the catalyzer element.
The lamella design significantly contributes to improving the distillate. The innovative catalyzer technology guarantees the reduction of unwanted acid content as well as cyanide and ethyl carbamate levels well below the legally stipulated limits. A complete cleaning does not require the dismounting of any parts. To suit lower ceiling heights, the catalyzer can also be mounted at the side of the distillery. Due to the vertical design of the lamella catalyzer, the distillation process does not require any pressure, which achieves excellent flow conditions and maximum efficiency. Sensory and scientific studies conducted by Hohenheim University have demonstrated the indisputable qualitative advantages of distillates produced with our catalyzer.
No excess phlegma buildup
Retention of heavy components
Delayed tail cut formation
Distillates produced with Holstein catalyzers usually score the best in blind taste tests.

[DAD300]

All this points to copper on the Ascending (column side is good to convert and trap the EC Precursers) and copper on the descending side (in contact with vapor or liquid is bad).

One or more of the articles state that new distillate, in contact with copper or copper salts, will continue to make EC as the alcohol matures!

The only question left for me, is can copper or copper salts be carried over the top to a stainless descending condenser path? I think not!

I will continue to have copper mesh on the column side only. Lately it has been at the top of the column to make it easier to clean. In the future I will add a "T" at the bottom of the column and take the copper mesh in and out of the "T".

It's funny that in other threads we have discussed the use of a copper packed section in the vapor of a pot still.

Holstein, Vendome and Kothe all offer it as an accessory. I always thought it was a passive reflux accessory.

[Odin]

Does that mean copper catalyzes are no good?.

They are, when placed as low in the vapour path as possible, to get the best of both worlds: catalystic reaction as well as prevention of copper contamination.

Regards, Odin.

[bearriver]

Awesome contribution Dad! This is very exciting stuff.

The master distiller at St. George Spirits in Alameda, CA touched on this while running what appeared to be a Holstein. To paraphrase, he said there is no copper after the plates. The reason was to avoid unwanted interactions between the liquid and copper that affects the flavor of the apple brandy he was running.

His comment has bugged me for over a year now, but I think this is why he made that comment. Now I get it.

Consider my mind officially blown.

[thecroweater]

Sorry for repeating myself over and over but the fact remains true that the copper salts that is claimed to do this are exhausted in the first few millilitres of the run, surely you guys agree with that. I am not anti stainless, glass, ceramic, earthenware, or what ever in the descending path. My point is and has always been that copper is very very necessary in the ascending path of vapour, this every one seems to agree on yes? and all things considered copper is not bad in the descending path unless one is considering drinking fore shots. can we agree that the acetone will clear the vapour path of all copper oxidization and if we can't agree on that then we say that what should be the heads cut has well and truly done this. It seems we all agree that no copper in the vapour path is a possible safety issue, it seems to me the stumbling block is to whether there is a real or hypothetical issue with copper in the descending path and I think based on how we as home distillers do cuts any problem is purely hypothetical and the reality is it is not, further more as there is no copper oxide left the copper in the descending path will continue to circumvent the production of the said compounds. This was my view from the start and as not one argument has addressed that reasoning it remains my point of view. I am after the same thing you guys i expect are and that is the truth of the matter

[Dan P.]

I'm with Croweater on this one.
The facts as I see them;

Urethane/Ethyl Carbamate; Wikipedia says this is "not acutely toxic to humans" and the IARC give it a rating of 2A, i.e. probably carcinogenic (compare to ethyl alcohol which is rated 1, i.e. proven carcinogen (just sayin'!)).

Copper; Not toxic in levels likely to be absorbed during condensation (my paraphrase).

Other gunk in your condenser; Clean that shit out!

When it comes to discussing this stuff, it would be awesome to leave out red-herrings like Wilson's disease (a cause, not result, of copper toxicity), and if someone can give me reference for an EU or German safety directive (or related study) for the replacement of copper with stainless condensers shown in the above pics, then I will be happy to accept that reason over the fact that s/s is cheaper and less of a faff to clean.

[Dan P.]

And, with all due respect to our esteemed colleague, I, for one, take Odin's "strongly stated" exhortations, such as to remove copper from the home distillation process (see link above), with a pinch of salt. Given that he is a commercial purveyor of stainless steel stills, I don't think that's ureasonable?
Just sayin'!

[emptyglass]

Stainless for liquid, copper for vapor is a reasonable point of view to take.

that is, stainless for the bottom of the boiler, copper from there on.

The necessity for copper in the descending path is a take it or leave it scenario.

If you are playing with fruit products there may be some relevance, but taking one paper from the interweb and running with it dosn't mean its supported by all. After all, copper has been used in distilling for a few thousand years now, its got a proven track record. Stainless is a relatively new material in comparison.

DAD300, if you want to make hooch thats safe for infants and pregnant women, I wish you luck, but until you have it approved by all relevant heath authorities, stick with the fact that drinking booze comes with risks. If you don't like the risks, give up drinking.

The internet is both the greatest source of information and misinformation at the same time.

[DAD300]

Oh, I'm going to drink...and I'm certainly not telling anyone else what to do.

Copper has been used for thousands of years and only removed from direct cooking utensils where acidic compounds touch it in the last century! Oh, then the removed it all togther by lining everything...except the French. They love something that happens between copper and eggs.

The source of the post info comes from at least ten research papers. Yes there are countries testing booze for toxicity before allowing sale. The U.S. doesn't. Hmmm... I now know Brazil and some Asian countries do. I remember manu had to retest multiple times to get a pass. And his stills are Stainless.

I will ask this, are there any other countries that do testing on alcohol beverages as a food product? I'll be looking also...

[bearriver]

The potential of their being another advancement is this hobby is awesome. Not saying that is what this is or isn't, but it would be a shame if the membership quit exploring new ideas. Including scouring the internet for relevant, quality data.

You either got extensive training in how to source information from your educators or you didn't. Simple as that. Only the folks who didn't think it is a simple matter.

PS Wikipedia is NOT a source.

[Dan P.]

You either got extensive training in how to source information from your educators or you didn't. Simple as that. Only the folks who didn't think it is a simple matter.

PS Wikipedia is NOT a source.

I agree entirely. The problem is that without being able to "source the source", i.e. obtain full disclosure of who funded any given study, "papers" pulled from the internet are only about as good as wikipedia.

[thecroweater]

at lest Wikipedia almost always lists is references and sources. Look ideas and theories are great and exploring them is how to grow knowledge but when you state a theory as fact then you damn well better prove your argument. Roll up with a cart blanche statement and your only evidence is hand full of out of context exerts of statements gathered together by some source you state you don't wish to reveal. When someone questions those theories with factual statements and you choose not to address them its very telling that either you don't have the answer or you don't have the answer you want. I'm not some back block luddite loath to change and as a mod my prospective isn't necessarily worth any more (or less) than anyone else's but here's how I am.
I'm quite open to any different ideas on anything and enjoy the discussion on it but anything pushed across as fact has to be shown as fact if not I will be the first to tear it to pieces. The argument here is that copper is bad in the descending path and it is based on "unrevealed" sources, red herrings, misdirection and conditions that don't or should not exist. Not one point has been shown to be an absolute fact and this leads to the conclusion that that it is not fact, certainly not a proven fact. The only fact I've really seen is some photos of some stainless PC's, whoop dee doo there could be a whole range of very obvious reasons for those guys to use them. If I put up a thousand photos of copper ones does that prove that copper is the only way to go? don't be obtuse of cause not. my conclusion is and people can draw there own, is copper being bad in the descending vapour path is complete horse shit unless you have some reason to worry about possible fores contamination but there is a very strong argument for having copper in the whole of the ascending path and suit your self after that if you are satisfied that no more amelioration is required beyond that point. As I have stated before, in the world of facts every idea doesn't get a prize

[Bagasso]

Wikipedia almost always lists is references and sources.

But it can be incomplete. Your link talks about one way EC is created. That doesn't change the fact that the other studies ended up with trace amounts of EC from glass and greater amounts from copper. While the reason might not be known, I think there is strong evidence of causation and not just correlation.

What happened to HD's policy to err on the side of caution?

[DAD300]

I keep trying to give up on this, but I'm afraid resistance is making it hard.

Some are misquoting my excerpts as though you aren't reading them. I post the excerpts because I know few will actually go out and read a research paper. I make no attempt to edit the quotes.

O.k. so here is a whole article.. http://onlinelibrary.wiley.com/doi/10.1002/jib.14/pdf" onclick="window.open(this.href);return false;" rel="nofollow

http://onlinelibrary.wiley.com/doi/10.1 ... x/abstract
The formation and distribution of ethyl carbamate (urethane) during pot still distillation was investigated. Formation only occurred if the distillation was carried out in the presence of copper. Removal or chelation of dissolved or suspended copper prevented ethyl carbamate formation. When copper was present, during and subsequent to distillation, formation of ethyl carbamate was time-dependent. The degree of formation was maximised between pH 4 and 6. During the second or low wines distillation only 1–2 per cent of the total available ethyl carbamate was collected with the potable spirit fraction. The remainder was distributed between the feints (15 per cent) and the spent lees (84 per cent).
-----------------------------------------------------------------

http://onlinelibrary.wiley.com/doi/10.1 ... 4618.x/pdf" onclick="window.open(this.href);return false;" rel="nofollow

"Discussion
Elevation of natural ethyl carbamate levels, subsequent to distillation, only occured if the distillation was carried out in the presence of copper. When fermented worts were distilled in all-glass distillation apparatus there was no significant ethyl carbamate formation."

-------------------------------------------------------

WHO Vol. 96 VOLUME 96 Alcohol Consumption and Ethyl Carbamate

WOW.... 1,440 pages devoted to Ethyl Carbamate in Commercial Booze with copper mentioned 128 times.

I also found EU, Canadian and U.S. FDA articles on the subject. All of these were about how do we stop the formation of EC and all cite or mention copper as a positive catalyst and negative in the vapor or maturing distillate.

Someone brought up, don't worry about urea. Urea is a byproduct of all fermentation, in the local, yeast piss urea. I imagine that's a component of why Turbos suck. Yeast induced Urea in fermented foods produces EC but at about 20% the level of whiskeys, because of the copper. Ah...no copper in kimchi.

I also imagine that the Whiskey Lobby in Ireland and Scotland is quit capable of insuring, graft, they can keep their old equipment, carcinogenic producing or not!

Now, if you want a proper discussion...give us something back! How about someone present an article that says, FDA or EU researchers have concluded that EC in alcoholic beverages isn't of concern?

[moosemilk]

While the information given is interesting, and POSSIBLY relevant, I am not going to swap out all my copper in the descending path. First, I almost always double distill, which it shows lowers the problem of EC. Second, a lot of what I make doesn't get a chance to age lol. And for what does, again, I double distill reducing the amount of EC. If further studies are done and it's significant enough, then I'm up for putting in stainless lyne and worm.

Remember aluminum and the altziemers thing? Only to find the tests were not accurate and in fact false outcomes (yet that part wasn't put out there as much...nobody likes to admit being wrong).

This is something to keep an eye on and watch for further studies. But I'm keeping my copper that's been used for hundreds of years.

[DAD300]

Wikipedia almost always lists is references and sources.

But it can be incomplete. Your link talks about one way EC is created. That doesn't change the fact that the other studies ended up with trace amounts of EC from glass and greater amounts from copper. While the reason might not be known, I think there is strong evidence of causation and not just correlation.

http://onlinelibrary.wiley.com/doi/10.1" onclick="window.open(this.href);return false;" rel="nofollow ... 4618.x/pdf

"Discussion
Elevation of natural ethyl carbamate levels, subsequent to distillation, only occured if the distillation was carried out in the presence of copper. When fermented worts were distilled in all-glass distillation apparatus there was no significant ethyl carbamate formation."

This is no longer speculation...ethanol reacts with copper and forms EC. Even with trace amounts of copper during maturation (aging).

Good news...the EC can be kept on the column side with a copper catalyst! Copper ascending path is good, copper descending path is bad.

moosemilk...that's fine. It's fine because you know and have made a decision. No issue!

[moosemilk]

Not to disagree with you, DAD. I just like to see a lot more research before changing ways. Not just this hobby. I'm serious about quality with my drink, which is part of the lure to distilling myself versus buying rot gut.

Now with that, I am still working on my column build so it's easy enough to add a stainless shotgun or whatever I go with as i've not decided yet.

And as for carcinogens...i probably take in more going outside into traffic while having my smoke. that's meant as a bit of "true" humor. Sad but true.

[thecroweater]

so why do you think they found EC at even higher concentrations in full stainless still plants, not a lot of copper in chrome,nickel, steel alloys . urethane is created when you heat a solution containing urea nitrate and ethly carbamate that's the facts, copper ameliorates that and that is another long know fact, it also removes sulphide, and cyanide compounds also a fact. Stainless steel and glass don't do this, they are inert of close to inert and so can not improve anything and that's a fact, copper oxide is removed during the very start of a run and that's another fact, There are hundreds of thousands of studies on the net drawing up all sorts of conclusions. throwing out numbers like 1,440 pages on EC and copper mentioned 128 times means zip except there are at least 1312 pages that don't mention copper and those that do mention it at least half a dozen times but forgetting that (as fact often are) that is still a ratio 45 to 2 that don't mention copper, not seeing the "wow" here

[DAD300]

Urethane is ethyl carbamate...not created by.

I need some reference as to SS pots having higher concentrations, I have seen exactly the opposite.

US EPA says, Ethyl carbamate (also called urethane as a common name) is a chemical compound with the molecular formula C3H7NO2.

National Center for Biotechnology Information published, The carcinogenic potential of ethyl carbamate (urethane): risk assessment at human dietary exposure levels.

I'm surprised you can see the keyboard...come on reference something...give me something to read.

[thecroweater]

the references to it have been post by you and I. Ethly Carbamate is a compound, created or if you prefer caused