Copper in the decending path

[humbledore]

I think this is what crow eater was referring to, from Dad's first post:

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.

For the record I find this interesting and thank dad for bringing it up regardless of the conclusions we might each take from it.

[thisguy]

So what I got from this is that my all copper stills are giving me and my precious drink cancer? It does so because of the liquid coming into contact with copper in the descending/condenser path when its all cooled down, not from the hot vapor coming into contact with copper on the ascending path?

Copper in the ascending path is good, copper in the descending path is bad...

I'll be honest, we (or atleast I) do it in such small amounts (<5 gallon runs at a time). I doubt the EC being formed is going to do anything horrible, like knock 10 years off our lives. Specially cause I live in a city. I probably take in more walking to class or standing on the corner waiting to cross the street. Or when I go for a smoke. Or even when I dont go out for a smoke, and am just walking around campus taking in everybody elses smoke. Milwaukee loves that shit....

But with that being said, I think its interesting and Its something I think we should look into further, but wait for more studies before people go saying NO MORE COPPER ON THE WAY DOWN. I didnt read the articles linked here, cause I have my own research paper to write, buuuuuuuuut, research is really dependent on the way they conducted it, where they conducted it, what stills they used, what they distilled, how they fermented it, samples, etc... Plus, ethanol is a poison to begin with.

[myles]

The copper is a catalyst. If you have the precursors present then you can produce EC. Get rid of the precursors in the assending path and there are none left to cause a problem in the descending path or cask.

[moosemilk]

No matter the view we all have, it is definitely worthwhile to keep an eye on this research. After all, each of us are in this to make the best beverage of quality that we can. I'm not opposed to moving forward. I just like to see more before making a conclusive decision.

Thanks for starting this thread, btw. I have found it to be very interesting at the very least.

[InglisHill]

Man, with the amount of membership someone should have access to a GC so we can test this stuff?

Come on......

Hands up!

[Dan P.]

The copper is a catalyst. If you have the precursors present then you can produce EC. Get rid of the precursors in the assending path and there are none left to cause a problem in the descending path or cask.

This is what is ot clear to me. Can anyone explain this from the "no copper in the descending path" point of view?

[humbledore]

I've read the articles posted. I think the original blog that Dad referenced was in error when it states that stainless columns produced excess EC and copper was an improvement. That article is focused primarily on sulphur-odor compounds and apparently copper does help reduce those.

All of the scientific studies linked in this thread other than that blog indicate that copper is required for the formation of EC. Several of them talk about measuring actual dissolved copper in the distillate and determining how much is needed to catalyze all of the precursors into EC. Not very much. It is a little concerning to me that there is a detectable amount of dissolved copper in distillate at all. By contrast distillate produced in a glass still had very little EC, almost below detectable amounts. I wish they had measured EC from a stainless still. But I can assume the results would be similar to glass(?).

Now the assumption is that not having copper on the descending path would result in no copper in the distillate hence no or very little EC formation. That is not covered in any of the studies referenced here as far as I can tell. Just in the original blog post. So the question is, would copper end up on the distillate if it was only present on the ascending side?

I found a good article comparing a stainless still to a copper one, but only for sensory analysis of the resulting whisky. Interestingly, the conclusion is that copper condensers (descending path) play a notable role in reducing DMTS and other compounds which produce sulphury and meaty aromas, resulting in a cleaner whisky. It's the fifth reference on that blog post.

[Dan P.]

Now the assumption is that not having copper on the descending path would result in no copper in the distillate hence no or very little EC formation. That is not covered in any of the studies referenced here as far as I can tell.

This is what I couldn't quite work out. It was copper picked up from a clean condenser or from copper salts (copper crud/whatever).
The devil in the detail.

My other question (not rhetorical) is; Why is EC worse than any of the other many esters present in distilled spirits?

[DAD300]

The copper is a catalyst. If you have the precursors present then you can produce EC. Get rid of the precursors in the ascending path and there are none left to cause a problem in the descending path or cask.

Thank you...

Use copper on the ascending side to burn up the precursors, and catch the Ethyl Carbamate as best as possible. Have no copper on the descending side to allow any further formation.

Perfect, to the point and short . We have barely touched on the idea of precursors and copper in the maturation/aging stage.

Dan P. EC may or may not be worse, but it is the only one designated as a carcinogen.

humbledore we're reading the same stuff. I think there may be another reason for the copper not ending up in the drink. I've been reading about post aging filtration. The big boys use a set of filters before bottling, 5 and .5 micron. I haven't figured out if .5 micron would remove the residual copper at bottling.

[Bagasso]

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

I agree with you and was asking what happened to the HD safety police?

[thecroweater]

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

I agree with you and was asking what happened to the HD safety police?

you talking about stainless? yeah I personally agree that full stainless outfits should be discouraged but there needs to be an overwhelming consensuses before we could start warning ppl of the obvious dangers Good point though

[Bagasso]

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

I agree with you and was asking what happened to the HD safety police?

you talking about stainless? yeah I personally agree that full stainless outfits should be discouraged but there needs to be an overwhelming consensuses before we could start warning ppl of the obvious dangers Good point though

Since I was responding to DAD300 the agreement is with him and he isn't talking stainless only either.

Either way, the standing policy has always been to err on the side of caution unless...

[thecroweater]

well then you are talking about copper oxide reactions as a catylist and that has been addressed by the "safety police" many many times DO NOT DRINK FORE SHOTS because that is where it will be but as myles, myself and many others have attempted to point out only if there was not the copper needed in the ascending path so why wouldn't one assume you were talking about discouraging stainless or glass stills as these are the only stills that could cause any of the afore mentioned compounds to be in the descending vapour path

[Bagasso]

well then you are talking about copper oxide reactions as a catylist and that has been addressed by the "safety police" many many times DO NOT DRINK FORE SHOTS because that is where it will be but as myles, myself and many others have attempted to point out only if there was not the copper needed in the ascending path so why wouldn't one assume you were talking about discouraging stainless or glass stills as these are the only stills that could cause any of the afore mentioned compounds to be in the descending vapour path

Strawman.

The OP never said all stainless is better and his original link even states:

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.

[thecroweater]

well then you are talking about copper oxide reactions as a catylist and that has been addressed by the "safety police" many many times DO NOT DRINK FORE SHOTS because that is where it will be but as myles, myself and many others have attempted to point out only if there was not the copper needed in the ascending path so why wouldn't one assume you were talking about discouraging stainless or glass stills as these are the only stills that could cause any of the afore mentioned compounds to be in the descending vapour path

Strawman.

The OP never said all stainless is better and his original link even states:

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.

Yup and if you intend to use ya fores/early heads you'd be spot on. Other than that there will be no copper salts present so the argument is a hypothetical nothing that is why the "safety police" aren't scrabbling for their virtual batons
Stawman is a good description for most of the proponent posts of this thread cool theory but that's where it stops

[Bagasso]

Yup and if you intend to use ya fores/early heads you'd be spot on other than that there will be no copper salts present so the argument is a hypothetical nothing that is why the "safety police" aren't scrabbling for their virtual batons

But the HD safety police prefers to err on the side of caution and I have seen them scrammble under similar circumstances but I guess copper is sacred.

Stawman is a good description for most of the proponent posts of this thread cool theory but that's where it stops

Doesn't make your argument any less of a strawman.

[humbledore]

The OP never said all stainless is better and his original link even states:

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.

That last quote is problematic. It is not clear to me why a glass still would produce very low EC while stainless would produce high EC. The article makes it sound like EC is already present in the wash and we're getting rid of it with copper. But the research appears to show that EC is not present initially, we are forming it by exposing its precursors to copper. However copper has many other beneficial properties such as removing off odors. So you do need some copper even though it serves as a catalyst for EC.

[Bagasso]

That last quote is problematic. It is not clear to me why a glass still would produce very low EC while stainless would produce high EC. The article makes it sound like EC is already present in the wash and we're getting rid of it with copper. But the research appears to show that EC is not present initially, we are forming it by exposing its precursors to copper. However copper has many other beneficial properties such as removing off odors. So you do need some copper even though it serves as a catalyst for EC.

Sure, which is why the OP said that it should be kept on the ascending side.

[thecroweater]

maybe read back, it has been shown beyond all possible doubt there is zero concern for any caution that's why
PS yes humbledore you are right EC is formed by heating a solution of urea nitrite and ethyl alcohol, copper deals with it, nothing else you could make a still out of does, maybe a case drawing a conclusion and finding results to fit. To say you can't get EC without copper is ridiculous

[humbledore]

I'm just saying that at least one paper showed that glass stills produce very little EC. And copper stills produced more. It shows it clearly.

Edit: to make my point more clearly, if all that is required to produce EC is heating a solution of urea nitrite and ethyl alcohol and copper removes it then the glass still would have measurably higher EC. And the opposite is the case.

[humbledore]

from "ETHYL CARBAMATE FORMATION IN THE PRODUCTION OF POT STILL WHISKY":

sorry it wouldn't let me copy so here's a screenshot.

[thecroweater]

I'm just saying that at least one paper showed that glass stills produce very little EC. And copper stills produced more. It shows it clearly.

yes and the highest level of all found in stainless stills so what to make of that maybe there was different levels of EC in the washes from these tests or some other variable

[DAD300]

As plain as possible....procurers (Urea is just one) in hot ethanol (vapor or liquid) react with copper to produce EC's!

So, safety says, produce the EC's in a copper catalyst on the ascending side and the EC's and copper can't make it over the the descending side. Then, if there is no copper on the descending side, any precursors that make it over can not become EC's. And no copper will make it into the distillate, where the same reaction (copper and precursors making EC's) can take place during long term cold storage.

Crow...you're getting more obvious that you are misquoting things.

Oh, I will say all Stainless would be an improvement over copper in the descending path, relating to Ethyl Carbamate.

If there were NO copper any where, the precursors would not form EC. Urea and sulfur compounds would make it over to the distillate without becoming carcinogens. Just bad flavors...

But we do value the other positive actions of copper. Soooooo, keep the copper on the ascending side of the still! The copper can't carry over in the vapor.

Bagosso, you are right, on several accounts.

I'm not promoting 100% removal of copper. I see positive aspects of copper. But I certainly think it has to be a managed use. Again, look at why copper cooking utensils were eliminated.

But I will say, the Russian and Eastern Europeans have been 100% anti copper for years. They think we are fools for "tainting our neutral with copper."

[DAD300]

crow...show me anything about all Stainless producing more EC's....

You think people producing these studies didn't use the same wash for all the tests?

[thecroweater]

ok a quote from your first post and from whiskeysience blog which I'm sure you could find the reference for it
DAD300 posted
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.

[humbledore]

I cannot find a reference for that quote croweater and I looked. I have been searching for info on EC and stainless stills, I'm not biased, looking for any info. I found this at the end of "Ethyl carbamate kinetics in double distillationof sugar cane spirit", but it actually references a different paper that I don't have access to titled "Influence of the distillation processes from Rio de Janeiro in the ethyl carbamate formation in Brazilian sugar cane spirits". In that study they look at EC formation over a variety of stills. I'll summarize the findings here (EDIT these measurements are supposed to be micrograms per liter the power of negative one, can't type that) :

Mean content of EC in all samples - 160mg L-1
double distilled in copper - 17mg L-1
single distilled in stainless - 11mg L-1
continuous column - 320mg L-1
single distilled copper - 145mg L-1

So here is one study showing low EC from stainless. This would back the idea that copper encourages EC formation. Not sure why it's so high in the continuous still (?).

[Dan P.]

from "ETHYL CARBAMATE FORMATION IN THE PRODUCTION OF POT STILL WHISKY":

EC-copper-glass.png

sorry it wouldn't let me copy so here's a screenshot.

Okay, so this, like the various studies posted, shows an increase in EC after the spirit run is complete, exponential, which suggests that copper salts/oxides/copper nasties present in the distillate itself are causing it, not the interaction with the condenser.

But is that because the condenser is oxidised/dirty?

[Bagasso]

maybe read back, it has been shown beyond all possible doubt there is zero concern for any caution that's why

Guess you don't know what "err on the side of caution" means.

[DAD300]

Here's the whole paragraph...

"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 diminish the amount of copper residues in the new make."

The problem was the new SS Columns, still had Copper Boilers and Copper Condensers.

This was one of the major points of the Brazilian Rum Paper.

They used multiple stills, as in:
-copper column with copper condenser
-stainless boiler with stainless condenser
-stainless boiler with copper condenser
-copper boiler with stainless condenser.

The worst possible combination would be stainless boiler, with a copper condenser. All the precursors would make it to the copper and drop into the distillate.

This is why most of the new stills have a CATALYST section added. Just like we can add a ball of copper mesh between the boiler and column on our Stainless stills.

humbledore...unfortunately they didn't describe the continuous column, but if it was like Bundaberg's it would be all copper, low wines at a low ABV with lots of components carried over. But those heavy EC low wines would get distilled again.

Here's some other strong language, "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 diminish the amount of copper residues in the new make."

You getting what that says? Copper condensers, add copper to the distillate. And that added copper in the distillate makes EC's during aging.

So copper condensers, even at the "big boys," used every day, add copper to the booze. How's that happen?

And the copper in the distillate reacts to make EC's while aging. The chart humbledore posted says the EC's increase from 10ppb to 60ppb in 48 hours.


Previously, I didn't link to the Wiley's Library post because it is a pay service and the links circumvent the pay part.

[bearriver]

I have no dog in this fight. But, at this point y'all are arguing for the sake of arguing to no benefit to this forum. Been there myself. I get it. We know your opinions already. This is turning into a pissing match and nobody is going to give ground. Respectfully agree to disagree already.

If your not posting links to academic research and data, then I see no reason to keep posting at all. If you must argue, doing it in a PM would save the rest of use from having to sift through it all for something tangible. Please.

Posted as Dad was posting....