So, the answer was copper

[Bagasso]

So if I've comprehended this post correctly...some of you are getting fermented washes that smell of sulfur? Like garlicky,sweaty armpit sulfonamides smell? In the wash?

Not quite. I get something off that doesn't smell like anything you describe and when I run it I get tails coming over after the first 250-300 ml and through the rest of the run.

Read a long time ago about wine faults and the penny test. By process of deduction, as explained in a run down of that test, if you drop a copper penny in a faulty glass of wine and the fault disappears then the culprit was sulfur.

I dropped copper into a wash with this fault, let it sit and it cleared up.

That is where it's at and nothing anybody says is going to change that.

The question that remains is, is copper exposure in an all copper still enough exposure? That sounds like, how long is a piece of string? It is a moving target and nobody has the answer.

But I can build an all copper still and hope, place copper in key spots on my existing still and hope or I can park my wash for a day with copper in it and be sure. You can do whatever pleases you but I'm going to go with no. 3, even if it takes the romance out of the process.

Now the next part is pure speculation on my part but I started thinking that if I was getting tails within the first 500ml of distillate, for whatever reason, from a typical 5 gal charge and looking at the boiling points of congeners and descriptions of "normal" runs the question that came to mind was, what makes tails "tails"?

The description sounds a lot like what wine guys call cork taint but I know I don't use cork so where does the "wet newspaper, dank basement, wet shaggy dog and musty" come from and, in my case, why was it coming over so early in my runs?

[Bagasso]

But also the counter-arguments are worthless IF it works in practice.

The ironic thing is that nobody is saying that it doesn't work. What they are saying is that it has to be in the still, as if there is some law of physics that says that exposure to copper only works if it is in the shape of a still.

It's like someone oaking with sticks being told "that doesn't work it has to be a barrel or you are just wasting your time", "hey you don't see commercial outfits oaking with sticks. Don't you think that if that worked they would be doing it?"

Of course there is a reason, volume of liquid to surface are of wood and all that. Same thing with this.

[Bushman]

But also the counter-arguments are worthless IF it works in practice.

The ironic thing is that nobody is saying that it doesn't work. What they are saying is that it has to be in the still, as if there is some law of physics that says that exposure to copper only works if it is in the shape of a still.

It's like someone oaking with sticks being told "that doesn't work it has to be a barrel or you are just wasting your time", "hey you don't see commercial outfits oaking with sticks. Don't you think that if that worked they would be doing it?"

Of course there is a reason, volume of liquid to surface are of wood and all that. Same thing with this.

This is getting away from copper but to add to your comment on oaking, several vendors at this years ADI National Conference were selling alternatives to barrels including oak sticks.

I use sticks to kick start my aging before putting them in barrels. For me I think I get more out of my barrels by speeding up the process. I also sometimes use my Ultra Sonic machine prior to adding the sticks.

[Bagasso]

This is getting away from copper but to add to your comment on oaking, several vendors at this years ADI National Conference were selling alternatives to barrels including oak sticks.

My comment wasn't about oaking per se, but rather on the appeal to commercial practices as an indicator of something working or not. Traditional oaking in barrels and the hobby alternative were just the example.

I'm guessing that the hobby side of things has a lot to do with these alternatives coming to market. Specially in today's market with an increase in micro producers.

Although it might be moving away from copper, it fits well with the idea that one size does not fit all.

[Bagasso]

For what it's worth, my jacking experiments have concentrated flavor more than alcohol, so now I only jack unfermented fruit for liqueur experiments.

I jacked it because it was such a small amount and I wanted to up the ABV to reduce the risk of infection while I tinker with it a bit.

I do a 2 step jacking: collect 75% of the first freezing then refreeze and collect 50% of the original volume.

Freeze 2l of wash and collect 1.5l
Refreeze the 1.5l and then collect 1l

I have tried running the left over ice from this kind of jacking through my still and got next to nothing before my thermo hit 100°C.

[SaltyStaves]

Well this is embarrassing. My wash is flawless.
The water in my outer heating barrel was responsible for the odour. Looks like washing soda wasn't sufficient to keep the water from turning.

I won't add any copper to the wash this time. Maybe I'll split the low wines and experiment there.

[NZChris]

I took the copper out of the wash this morning and it looked exactly the same as it did when it went in. No patina gained or lost. The wash was already so good the experiment was never going to make a difference I could pick.

[Bagasso]

It stands to reason that some won't see a difference.

You have to have the problem to notice a change.

Might be interesting if some see an improvement even if they thought they didn't have a problem. Like the lava rock threads where some saw improvements even if they thought there wasn't room for improvement. Then again I might just be remembering wrong.

Then there were those who didn't notice any difference.

[jb-texshine]

Im game to try out any experiment but im gonna have to wait till summer screws one up for me to try. I do think it bears investigating though.

[Bagasso]

A small update.

Last night I stripped a liter, yes a whole liter, of jacked wash that I had sitting on copper.

Stripped up to 98°C and right off the bat I noticed that it was missing the usual suspects; wet paper, cardboard or dog. It was stripped low wines so, when I took a small sip it was no surprise that I got numb lips and a bitter aftertaste but the smell was really clean.

One thing that surprised me was that it wasn't solventy. Who knows what went on there but, at least I get the feeling that this "product" is a closer match to what others describe.

[der wo]

Bagasso,

another experiment for you would be to add copper salts instead of solid copper to your washes. Wine makers do it. You could try 1g copper sulfate per 10l mash (it's the European Union limit for wine) or copper citrate.
I have read several German language articles about that. It sounds promising. Google "copper sulfate wine".

[Bagasso]

another experiment for you would be to add copper salts instead of solid copper to your washes. Wine makers do it. You could try 1g copper sulfate per 10l mash (it's the European Union limit for wine) or copper citrate.

I've read about it but I'm not sure if or where I could get it locally. I've read that you have to add 4 times the amount that you would of copper because of the actual copper content of the salts.

In this thread someone talks about using it and warns about it producing sulfuric acid and possibly nasty esters.
Don't use CuSO4 to treat Sulfur Issues

Not sure how true that might be. I mean they do use it in wine.

On the pure copper front, I put my usual sugar wash down. 16L @10%.

Changed 2 things. 20-20-20 at 1.5 tsp and I placed the stripped copper from 40 cm of 12 AWG braided copper wire that I had laying around into the fermentor. It hit 0.990 in 54 hours. It actually finished faster than when I tried just the small (10cm) piece of wire. Probably the 20-20-20 but it doesn't matter why. What matters is that that amount of copper did not slow the fermentation down at all.

Of course it smells better than my usual wash. I plan on setting aside at least a small amount of wash with and without more copper to see if I notice any change.

[der wo]

Interesting thread.

When you add fine copper dust to the low wines and distill the product again there is a noticeable improvement.

I wonder why he didn't write something here.

I never read about a problem using copper sulfate. I have read a theoretical discussion in German about if sulfuric acid could be a problem, but no practial results. Boiling point 3XX°C. So it should be more a problem in wine than in spirits, in theory.
Edit: Sulfuric acid is recommended sometimes for lowering the pH of mashes.

I have distilled the low wines with the copper pipes now. It was experimental low wines, I never made before. So I cannot say if it is better or not. But I noticed something:
Normally I distill low wines without my copper agitator. This time I used it. After distilling a mash the copper is always clean of course. The low pH has washed away all copper compounds. But low wines aren't as acidic. The boiler was half full only. So the wings of the agitator were partially over liquid level. Here a picture of a wing:

right the upper part in the vapor is pink. Left the part which was in the low wines is orange-yellow-green.

Another picture of a wing in the liquid with stronger colors:

Obviously the copper reacts. And obviously it's not an oxidation only. The yellow orange is perhaps an oxide. The green is probably the sulfate. Or acetate or carbonate?

[der wo]

Some more quotes from MDH from:
http://homedistiller.org/forum/viewtopi ... 38&t=46808
http://homedistiller.org/forum/viewtopi ... 94&t=48881

Make copper carbonate with copper sulfate and baking soda solutions combined. Filter the solids through coffee filters, then wash the resulting blue solids several times through the same filter with water. Remove the copper carbonate from the filter and put it in a beaker/glass etc, slowly add a solution of either citric acid/lemon juice or "Acid blend" from winemaking shops. You'll get bubbling and then have a blue solution of organic copper salts.

Another way to do it is take "Acid blend" from a winemaking shop and boil some copper in a solution of it until the solution turns bright blue.


1. Combine solutions of copper sulfate with sodium bicarbonate, a solid will be created, capture this solid using coffee filters and run a bit of water through it to clean it out. This is copper carbonate.
2. Buy "Acid blend" at winemaking stores. This is a combination of malic and tartaric acid. Make a solution of this and gradually react it bit by bit with the copper carbonate until bubbling stops and a blue solution is left.
3. Store this away and use it with discretion.

Copper sulfate I don't like because it will react in such a way that is undesirable in distilled spirits. This solution (Which is copper tartarate and malate) can be added to low wines of sulfured distillate, and then that distillate can be redistilled. The copper stays behind in the still and the resulting liquid is free of sulfur flaws.


Copper reacts with sulfur producing insoluble copper monosulfide which stays behind in distillation. Don't use copper sulfate as that is killing fire with fire.


I will try out to boil copper in citric acid.

[der wo]

I will try out to boil copper in citric acid.

Doesn't work. It needs oxygen for the reaction probably.
So I will place the copper not fully covered by the citric acid solution. Everyone who ever cleaned the still with citric acid and forgot to rinse after that knows that it works...
Or I add H²O² (but have not at home).

[Bagasso]

Obviously the copper reacts. And obviously it's not an oxidation only. The yellow orange is perhaps an oxide. The green is probably the sulfate. Or acetate or carbonate?

The wiki entry for Copper(I) oxide or cuprous oxide says "The compound can appear either yellow or red, depending on the size of the particles."

Maybe this explains the color on your copper pieces in low wines.

It does seem counter-intuitive to use copper that has already been reacted with sulfur (copper sulfate) to react with sulfur compounds but that is what the wine sites say. It also seems to be the first step in getting any of the other compounds. Citric acid will only strip the oxide layer, which is what seems to be happening by soaking copper in wash.

Since copper in the wash isn't a problem for distillers I don't see the reason for going through all the trouble of making sulfate and then turning that into carbonate. I might consider it if, like I said earlier in the thread, I find any washes that I might just want to keep as is and knowing how much copper is in the "wine" would be a good thing.

[der wo]

Citric acid will only strip the oxide layer, which is what seems to be happening by soaking copper in wash.

No, it works if air is present. I got a lightly blue color after one day. But I ended the experiment, because I will never be able to measure how much copper is solved. Perhaps I will try it with H²O². But here would be the same problem.

To make copper carb from copper sulfate is easy. But I would prefer to buy it. So I know that it is pure. I also could buy copper carbonate or copper oxide. What would be the best one? As long the wash is acidic, anyone of them will solve I think. And because I found copper pipes work even in low wines, I think low wines are acidic enough too. So perhaps I prefer the oxide, because it doesn't add something to the mash what could affect the pH for example. But perhaps the effect is much slower than with the very easy soluble sulfate. Too many options .

[Bagasso]

No, it works if air is present.

True but then you are making more oxide so that the acid can dissolve it. It isn't the acid itself that is oxidizing it.

But I ended the experiment, because I will never be able to measure how much copper is solved. Perhaps I will try it with H²O². But here would be the same problem.

But it is only a problem if you are going to drink without distilling or if not knowing bothers you.

To make copper carb from copper sulfate is easy. But I would prefer to buy it. So I know that it is pure. I also could buy copper carbonate or copper oxide. What would be the best one? As long the wash is acidic, anyone of them will solve I think. And because I found copper pipes work even in low wines, I think low wines are acidic enough too. So perhaps I prefer the oxide, because it doesn't add something to the mash what could affect the pH for example. But perhaps the effect is much slower than with the very easy soluble sulfate. Too many options .

I guess one would have to see what is available and if one works better than the other. Oxide is what we all have on hand, formed on the copper pieces we have laying around and that just seems like the easiest, because it is already there.

While sulfate doesn't seem to cause problems in wine, who knows what effect it has during distillation.

Copper carbonate is actually a salt of copper, carbonic acid and hydroxide so I don't think it is alkaline. It is also such a small amount that I doubt it will have any significant effect on pH.

[der wo]

No, it works if air is present.

True but then you are making more oxide so that the acid can dissolve it. It isn't the acid itself that is oxidizing it.
But it's blue. So it is copper citrate. An oxide would be yellow, red, brown or black. I used distilled water. There is nothing except water copper and citric acid and air.

But I ended the experiment, because I will never be able to measure how much copper is solved. Perhaps I will try it with H²O². But here would be the same problem.

But it is only a problem if you are going to drink without distilling or if not knowing bothers you.
Yes. But generally I want to know how much I use and at the end how much it needs.

To make copper carb from copper sulfate is easy. But I would prefer to buy it. So I know that it is pure. I also could buy copper carbonate or copper oxide. What would be the best one? As long the wash is acidic, anyone of them will solve I think. And because I found copper pipes work even in low wines, I think low wines are acidic enough too. So perhaps I prefer the oxide, because it doesn't add something to the mash what could affect the pH for example. But perhaps the effect is much slower than with the very easy soluble sulfate. Too many options .

I guess one would have to see what is available and if one works better than the other. Oxide is what we all have on hand, formed on the copper pieces we have laying around and that just seems like the easiest, because it is already there.

While sulfate doesn't seem to cause problems in wine, who knows what effect it has during distillation.

Copper carbonate is actually a salt of copper, carbonic acid and hydroxide so I don't think it is alkaline. It is also such a small amount that I doubt it will have any significant effect on pH.
Yes. But why don't use the wine makers the carbonate? The sulfate is cheap, ok. But the citrate not I think. The carbonate would be cheaper and is probably in wine very soluble. Where is the downside of the carbonate? That's why I tend to use the oxide.

[Bagasso]

But it's blue. So it is copper citrate. An oxide would be yellow, red, brown or black. I used distilled water. There is nothing except water copper and citric acid and air.

Yes, but once the oxygen is used up and no more copper oxide is created the acid has nothing left to dissolve. That is what makes it difficult to figure out how much ends up dissolved in the liquid.

Yes. But generally I want to know how much I use and at the end how much it needs.

Somehow, I knew that was the real reason. Nothing wrong with that.

Yes. But why don't use the wine makers the carbonate? The sulfate is cheap, ok. But the citrate not I think. The carbonate would be cheaper and is probably in wine very soluble. Where is the downside of the carbonate? That's why I tend to use the oxide.

It takes extra steps and materials to make it so, I don't think the carbonate would be cheaper.

Just a quick search on amazon and it shows 653 hits for carbonate but 2,091 for sulfate. Also Carbonate at $10/lb and sulfate at $3/lb. Nothing scientific about that information but it is something. Less availability and, at least to final consumers, there is a difference in price.

It could also just be tradition.

[der wo]

But it's blue. So it is copper citrate. An oxide would be yellow, red, brown or black. I used distilled water. There is nothing except water copper and citric acid and air.

Yes, but once the oxygen is used up and no more copper oxide is created the acid has nothing left to dissolve. That is what makes it difficult to figure out how much ends up dissolved in the liquid.

That's why the copper has to be constantly aerated. First it has to get oxidized. Either by not covering the copper complete with the citric acid solution (slow) or with the help of H²O² (fast).


You are right with your comment about the price.

[der wo]

Probably not important, but I yesterday buyed some H²O², so here a little test:

1g copper
1g citric acid
10ml H²O² 3%
two times short microwave heated

[Bagasso]

Probably not important, but I yesterday buyed some H²O², so here a little test:

Doesn't look like copper. Is that a coin? Was it just coated?

If we could get a whole piece to dissolve with a known weight then we should be able to meter out how much copper one might add by adding the solution.

[der wo]

It's a ring cut off from a copper pipe.
I just measured the weigth of the ring. It has lost at least 10%. So I now have 10ml with 0.1g soluted copper, residual compounds of the citric acid and water.
To get the whole piece dissolved should be possible. But a stronger H²O² (up to 30% is available online) would speed up and end in a more concentrated solution.

BTW, It is the same procedure to produce copper sulfate from copper, H²O², and sulfuric acid (instead of citric). You can see many videos on youtube.


I did another experiment:
I produced copper carbonate from copper sulfate, washing soda and water. And washed and filtered it. It is still a wet paste, so I don't know how much is water and how much is the carbonate. I stirred 1/2 teaspoon of the paste in a fermenting pear mash (12l), which has a slight sulfuric smell. Overnight the smell has gone. I don't have an untreated sample, so perhaps it's not because of the copper, also time cures it often. But a good result is, that the fermentation speed was not affected, the yeast is still happy.

[Bagasso]

It's a ring cut off from a copper pipe.

I thought it looked silver but I guess it's just the light color of the clean copper and the tint of the liquid that makes it look like that.

I just measured the weigth of the ring. It has lost at least 10%. So I now have 10ml with 0.1g soluted copper, residual compounds of the citric acid and water.
To get the whole piece dissolved should be possible. But a stronger H²O² (up to 30% is available online) would speed up and end in a more concentrated solution.

I guess it doesn't really matter how concentrated the solution is as long as you can figure out how much copper you are adding.

Say you add 5ml of your solution and it takes care of a flaw in 20l of wine/wash. You would know that you added 50mg of copper. You could even choose to drink without distilling and be sure that the copper added is below safety limits.

BTW, It is the same procedure to produce copper sulfate from copper, H²O², and sulfuric acid (instead of citric). You can see many videos on youtube.

I have been looking at some but have not had the time to try anything.

But a good result is, that the fermentation speed was not affected, the yeast is still happy.

That is good to know. I just threw out the sample of wash that I had aerated and then placed copper in and it did not clean up as well as the wash that received copper right away or the wash that I recently made.

I think if the problem can be cut out as soon as possible (in the fermenter) then, why not?

[der wo]

It is the flash of the camera. I had to decide for a shiny blue (with flash) or a pink copper (without flash)...

Perhaps you can try one of the options. Carbonate, citrate or oxide. What's easiest for you. I am curious your results.
I stirred in the carbonate two days after the fermentation peak. I have read, yeast absorbs copper. So perhaps it is not optimal to add the copper at the beginning of fermentation. Absorbed copper doesn't help against sulfur and will harm the yeast perhaps.

[Bagasso]

Perhaps you can try one of the options. Carbonate, citrate or oxide. What's easiest for you. I am curious your results.

In theory I have been using oxide, I just don't know how much.

I stirred in the carbonate two days after the fermentation peak. I have read, yeast absorbs copper. So perhaps it is not optimal to add the copper at the beginning of fermentation. Absorbed copper doesn't help against sulfur and will harm the yeast perhaps.

I added my copper pieces before pitching the yeast. Helped with the flaw and didn't have any negative effect on the yeast.

[Bagasso]

I seemed to have run into an inconvenient fact. Despite not stilling all that much I have noticed that my copper bits are not tarnishing fast enough between uses so it seems a bit of copper citrate solution will have to be made up in the near future.

[der wo]

Hot copper oxidizes fast. I don't remember how fast. But perhaps try to place the copper in an oven.

[Bagasso]

Hot copper oxidizes fast. I don't remember how fast. But perhaps try to place the copper in an oven.

Copper patina is supposed to only be around .06 microns thick so, if I'm going to spend time on it I may as well go straight to chemical oxidation.