Coppery slick and metallic back flovour

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Octopus
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Coppery slick and metallic back flovour

Post by Octopus »

Hi, my distillate has a metallic taste I just can't get rid of, it's not great. I'm really disappointed after this last run as it has all gone swimmingly, I put so much effort in to this one (not to mention money), but notice the taste in the background has effectively made it not that great at all. Even visual evidence now I'm pretty sure of the taste that is there, reddy brown particles on an oily slick, I understand the oily slick could be normal at times, it's the coppery looking particles I'm questioning.

This time was an Everclear (Popcorns recipe), everything was going well on the first bucket, clear as on the stripping run until after a litre or so, where the colour started becoming not clear. By the end (5L) it had a browny yellow hue and had a floating slick on top made up from these particles. The second bucket came out in the exact same manner, first clear, then started to discolour, and oily slick of particles. Recently I thought I'd add a tiny bit of copper mesh to the collector (very little) just to give a wee bit more copper contact and thought it might have been this so removed it before doing my third bucket.

The distillate came out just like all of the others, I just don't know what to do!? I mean I don't "know" that's the taste, but it seems pretty damned obvious. The fear of it all saw me cleaning the collector good, and pouring a few rounds of boiling water through the condenser for good measure before doing the spirit run, I the strained the distillate through a muslin bag when putting it into the boiler and I don't see any issue in the collected final but it has a heavy musty metal flavour that really takes away from it all. It's making me avoid doing any more through the still until I know what's going on.

The still is newish, I did a vinegar run, then distilled water, and have done a sugar wash prior to this one a while ago, and that was not affected. This is basically the second distillation of alcohol so can't imagine I have done anything wrong for this to happen during the process. The particles look like copper filings for want of a better way of describing it.

Can anyone suggest why this might be happening, and/or do you think this flavour accent could be removed?

Thanks.
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Re: Coppery slick and metallic back flovour

Post by Deplorable »

You did a single run, all into one collection vessel?
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Re: Coppery slick and metallic back flovour

Post by tjsc5f »

Were you stripping on the grain? I've had dark oils come through when steam stripping on grain. They will stay behind on the spirit run though.
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Re: Coppery slick and metallic back flovour

Post by Salt Must Flow »

Do you think it puked? Often discolored stripping runs have been determined to be due to a puke, especially when solid particles have passed through the still.

To be clear, this was just your stripping run correct?

With what type of rig do you intend to do your spirit run with?
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NZChris
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Re: Coppery slick and metallic back flovour

Post by NZChris »

It sounds perfectly normal for a stripping run.

Now do the spirit run.
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Re: Coppery slick and metallic back flovour

Post by jonnys_spirit »

Not sure what popcorns everclear recipe is but i’ve had the corn oils and dark metallic looking globules before too. It not metal - it’s from the corn. That all means good flavor to me and the spirit run cleans up real nice. For cleaning I only rinse and let the patina build up on the inside and outside too. Boiling acidic stillers beer and ethanol does a pretty appropriate cleaning job imho.

Let us know how it turns out after the spirit run and post a pic of your rig please for reference.

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Re: Coppery slick and metallic back flovour

Post by Demy »

Agree with the others, the dark color could come from cereals, in a stripping it is normal. The weird thing is the metallic taste, typically this happens with new polished or acid treated copper but should disappear after running with vinegar ...
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Re: Coppery slick and metallic back flovour

Post by NormandieStill »

Demy wrote: Sat Aug 13, 2022 9:52 pm Agree with the others, the dark color could come from cereals, in a stripping it is normal. The weird thing is the metallic taste, typically this happens with new polished or acid treated copper but should disappear after running with vinegar ...
I would expect it to be a consequence of running with vinegar, it being an acid. In my experience even if you clean the living daylights out of your copper, by the time you've stripped three charges there's enough patina for the taste to go away on the spirit run.
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Re: Coppery slick and metallic back flovour

Post by Saltbush Bill »

Octopus wrote: Sat Aug 13, 2022 2:47 pm This time was an Everclear (Popcorns recipe),
What is that and where did you find it? There is a good reason why we suggest that Newbs start with Tried n True recipes viewforum.php?f=14
That reason is that a lot of the members here know these recipes inside out making it easy to help you when problems arise.
Octopus wrote: Sat Aug 13, 2022 2:47 pm clear as on the stripping run until after a litre or so, where the colour started becoming not clear. By the end (5L) it had a browny yellow hue
It puked.
Octopus wrote: Sat Aug 13, 2022 2:47 pm The second bucket came out in the exact same manner, first clear, then started to discolour, and oily slick of particles.
Puked again.....oily stuff as others said probably from corn. Solve the puking by running slower or putting less in the boiler or both.
Octopus wrote: Sat Aug 13, 2022 2:47 pm heavy musty metal flavour
Heavy and Musty says Tails to me.....Is it really metallic or is it just bad tails?
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Re: Coppery slick and metallic back flovour

Post by Yummyrum »

NormandieStill wrote: Sat Aug 13, 2022 11:11 pm
Demy wrote: Sat Aug 13, 2022 9:52 pm Agree with the others, the dark color could come from cereals, in a stripping it is normal. The weird thing is the metallic taste, typically this happens with new polished or acid treated copper but should disappear after running with vinegar ...
I would expect it to be a consequence of running with vinegar, it being an acid. In my experience even if you clean the living daylights out of your copper, by the time you've stripped three charges there's enough patina for the taste to go away on the spirit run.
You git a few things going on there , but I agree that the metallic taste is due to fresh clean copper .
It drives me nuts when I hear blokes constantly acid cleaning their copper . Clean copper makes metallic booze .
A few runs ( without cleaning it ) and it will be seasoned and no longer have the metallic taste .

One advantage of the sacrificial run we always recommend is to help season the copper . Then some clever clot see’s its starting to go brown and acid cleans it . :econfused:

Not saying you did , just having a soap box rant .
Browny black copper doesn’t make metallic booze .Shiney pink stuff does .
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Re: Coppery slick and metallic back flovour

Post by zed255 »

I have to echo Yummy's comment on over cleaning a still, especially copper. Every time I made a change and recleaned my rig I got at least one run that tasted metallic afterward. Now I only rinse and dry and have learned to stop worrying and love the patina.

Also, oils from grains often have a silver, copper or bronze appearance. I've only noticed them when stripping fast and maybe even on the verge of a puke. Never an issue on a spirit run from low wines.
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Re: Coppery slick and metallic back flovour

Post by Trapped-in-Oz »

..

I am puzzled why clean copper is tagged as a cause of ‘metallic taste’… perhaps these experiences are due to other residues or solder...?
I light clean (with white kitchen vinegar) my copper and have never noticed anything ‘metallic’……. and the dark odour of what I wipe off the copper is reason enough.

..
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Re: Coppery slick and metallic back flovour

Post by The Baker »

[color=#0040FFI am puzzled why clean copper is tagged as a cause of ‘metallic taste’…][/color]

Don't worry too much about why.
It just does.

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Re: Coppery slick and metallic back flovour

Post by Trapped-in-Oz »

The Baker wrote: Sun Aug 14, 2022 6:07 pm
Don't worry too much about why.
It just does.



okay trust the experts, no evidence required.


..
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Re: Coppery slick and metallic back flovour

Post by NZChris »

If people who have done the experiment for me reckon it causes a metallic taste, I'm ok with that.

When I was doing my research, I didn't notice any emphasis on cleaning protocols in the literature, so I've never put any effort into cleaning apart from a hose out and a wipe around if the top of the pot is scummy after a set of stripping runs. Nobody has ever commented on a metallic taste in any of my finished product. When I have had fusels in the finished product, it was because I chose the cut when pissed and didn't do a recheck the next day before committing the jars to one vessel, not because the still was dirty.

The next run should reflux most of the remaining fusel oils back down into the pot before it starts producing. Fusels in the lyne arm and condenser are flushed into the jars that you would normally discard as heads, so they shouldn't be a problem either.

The only problem I've come across is when running gin through a tails contaminated Leibig, so I built a dedicated SS gin Leibig and don't bother cleaning that at all.
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Re: Coppery slick and metallic back flovour

Post by Yummyrum »

Trapped-in-Oz wrote: Sun Aug 14, 2022 9:46 pm
The Baker wrote: Sun Aug 14, 2022 6:07 pm
Don't worry too much about why.
It just does.



okay trust the experts, no evidence required.


..
I don’t clam to be an expert nor can I provide you with evidence .
All I can say is I have noticed on quite a few ccassions ver the last 8 or more years I’ve been building and modifying stills , is that I notice a Metalic taste .

No it is not flux . I physically wash and polish ( with a scrubber and then rinse) all internal surfaces . I have also noticed it when I have foolishly decided to acid clean my stills .

Once I cottoned on to when I was noticing the taste , it all made sense and now I do a sac run after modifications just to season it .

At first I never noticed it . IE when I build my first still . It was probably there but I wasn’t aware if it . Only after becoming familiar with the seasoned copper spirit did I notice it when run through clean stuff .
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Re: Coppery slick and metallic back flovour

Post by Bryan1 »

I don't do too many runs these days I have that much aging and ready to drink but my plate tree hasn't been apart since I built it, copper stills naturally patina and when the foreshots go thru they do give the internals a good clean, then the heads go thru doing the same job. After they have been taken back into reflux until all the plates load then the first cutjar goes into feints so I know my still will produce a top drop every time.

I always leave a bit of water in the boiler so the plate tree can tell me the humidity in the shed too :lol: so if all 4 plates are foggy it's really humid, only the top plate foggy it aint humid or very low etc.

Just remember everytime you break a seal a new seal is needed and I use PFTE gaskets I made myself so I just wrap 2 turns of tape around the seal and it's good as new again.
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Re: Coppery slick and metallic back flovour

Post by Trapped-in-Oz »

..

me thinks there’s a need for more emphasis on method and degree of how copper is cleaned……..

..
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Re: Coppery slick and metallic back flovour

Post by NormandieStill »

Trapped-in-Oz wrote: Sun Aug 14, 2022 11:34 pm ..

me thinks there’s a need for more emphasis on method and degree of how copper is cleaned……..

..
The consensus seems to be quite clear. Clean it really well after assembly (or purchase), scrubbing if possible and then vinegar run and sac run. And then stop cleaning it unless you really bugger something up, and even then you might get away with it (because you're chucking the first stuff off the still) unless your redistilling gin in which case you might need to reclean.
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Re: Coppery slick and metallic back flovour

Post by Trapped-in-Oz »

okay bows to the groupthink….. will go along with ‘the consensus’ and continue the repetition. Evidence not required.

..
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Re: Coppery slick and metallic back flovour

Post by NZChris »

Trapped-in-Oz wrote: Mon Aug 15, 2022 12:10 am okay bows to the groupthink….. will go along with ‘the consensus’ and continue the repetition. Evidence not required.

..
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Re: Coppery slick and metallic back flovour

Post by NZChris »

I don't agree with quite a few things that might be considered ‘the consensus’ by virtue of how many times they are repeated on this forum, Oz :D
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Re: Coppery slick and metallic back flovour

Post by Trapped-in-Oz »

NZChris wrote: Mon Aug 15, 2022 12:18 am
Trapped-in-Oz wrote: Mon Aug 15, 2022 12:10 am okay bows to the groupthink….. will go along with ‘the consensus’ and continue the repetition. Evidence not required.

..
Do whatever works for you in your shed. That's what I do in mine.

that's right and I'll be giving my copper a light clean........ Evidence not required.

..
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Re: Coppery slick and metallic back flovour

Post by NormandieStill »

Trapped-in-Oz wrote: Mon Aug 15, 2022 12:28 am that's right and I'll be giving my copper a light clean........ Evidence not required.
The problem with your application of sarcasm here is that you asked the question. There is a consensus. That consensus has been formed based on the experience (evidence) of many people over a fairly long time. If you feel that the consensus is wrong then your are free to experiment and to report your findings.

Groupthink is only a problem when it's based on repetition of a single opinion without basis in fact.
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Re: Coppery slick and metallic back flovour

Post by Trapped-in-Oz »

NormandieStill wrote: Mon Aug 15, 2022 1:50 am
consensus has been formed based on the experience (evidence)


Consensus may claim experience as evidence without verifiable experiment and doubting the Consensus is required to provide experiment/evidence.

Does the Consensus have a science based theory to support the assertion ?

..
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Re: Coppery slick and metallic back flovour

Post by Bryan1 »

Trapped-in-Oz wrote: Mon Aug 15, 2022 2:33 am
NormandieStill wrote: Mon Aug 15, 2022 1:50 am
consensus has been formed based on the experience (evidence)


Consensus may claim experience as evidence without verifiable experiment and doubting the Consensus is required to provide experiment/evidence.

Does the Consensus have a science based theory to support the assertion ?

..
Consensus may claim those on the prison island could have 2 heads and they cut the wrong head off doubting the Consensus to provide rational thought without any basis of science then many assertions can fly just like pig's flying backwards.

now that above text makes about as much sense as you have given this thread so without the experience it's best to read and learn and not try and be the expert savvy
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Re: Coppery slick and metallic back flovour

Post by Trapped-in-Oz »

Bryan1 wrote: Mon Aug 15, 2022 3:19 am

it's best to read and learn


thank you I'll do that......... and in the meantime perhaps the Consensus can provide a science based theory to support the assertion ? Please.

..
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Re: Coppery slick and metallic back flovour

Post by zed255 »

The only evidence I have rests in direct experience with clean vs patina. This means of course that most others can't examine my evidence as it doesn't come in the form of a publicly available scientific or academic journal.

I'm not a scientist, just a hobby distiller. I have no credentials, just my senses, experiences and basic knowledge. I do hovever recognize cause and effect.

I have observed that when I have completely bare copper (freshly cleaned with no patina or passivation) and do a run the product will have a metallic twang on the palate. I noted this when I was only using a packed column reflux setup and would clean it like it owed me money. After getting lazy and skipping a few cleanings I noted the metallic taste did not appear. Building new parts prompting me to reclean caused the taste to reappear.

I think it is more important to maintain the passive surface on the decending path than the ascending path, but that is more intuition than anything else as I've never experimented in such a fine grained manner. I don't believe the vapour will carry over any metal to cause the taste, but liquid product in direct contact with unpassivated copper certainly could which is the basis for my idea that the decending path is the critical one with respect to this metallic taste some report.
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Re: Coppery slick and metallic back flovour

Post by jonnys_spirit »

Good question. A still is just a pot to cook some stuff in. Basically a kitchen utensil. Certain pots and pans never see soap in my kitchen.

Boiling vinegar and boiling a strip charge are both acidic liquids. Boiling a higher abv low wines charge (high proof alcohol solvents) is also already a cleaning operation.

Additional cleaning other than a rinse is a pita and waste of my valuable time when i’ve already sterilized it with high proof hot ethanol vapor.

What is to be gained by making it shiny on the inside? If there’s a tangible benefit I’ll do it.

Seasoning a cast iron or carbon steel skillet is a well known and long standing protocol that produces better results when operating the tool. Maybe a bit of evoo on the inside of the still between runs would be useful since it is a cooking tool? I do already throw some evoo in on a strip to prevent pukes.

Cheers!
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Re: Coppery slick and metallic back flovour

Post by jonnys_spirit »

Here’s a little science.

https://www.corrosionpedia.com/definiti ... zed-copper

The so called patina buildup that we talk about is more akin to seasoning of a cooking utensil - not cupric sulfate. We don’t want the green verdigris. The seasoning protects against this and I suspect shiny copper reacts with O2 much sooner than seasoned copper and in turn comes over to some extent in distillate which folks have expressed in their tasting experiences.

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