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Don't use CuSO4 to treat Sulfur Issues

Posted: Tue Sep 24, 2013 6:32 pm
by MDH
Like anybody here, I am constantly learning - or in this case learning to listen to my nagging conscience.

I used to use copper sulfate to treat sulfur issues in distillate. A lot of the time, commercial wines and even simple mash will produce a lot of sulfur compounds that make fresh distillate smell very awful for the first seven days (think eggs, turkey, etc) because they contain sulfites or hydrogen sulfide. The common way to treat this in wine is with copper sulfate.

Well, I wasn't using my head. When I first started doing this to distillate, something in my mind said "Won't H2SO4 be liberated from the CuSO4 when you react the CuSO4 to produce CuS?" but I continued this practice anyhow, not thinking that the H2SO4 floating around could possibly produce some very nasty esters.

Well, today, I had a distillate that smelled very rancid and unpleasant but in the most subtle way possible. Half my friends couldn't detect it, so it drove me crazy. The problem? I had used CuSO4 before distillation!

So, to fix this, I reacted a bit of CuSO4 and ascorbic acid to get copper powder, which I rinsed with water. I poured the fine copper powder in the distillate and ran it again. Presumably, the metallic particles would displace the Sulfate esters I had created.

The result? This brandy now smells absolutely wonderful, better than both before and after the CuSO4 treatment.

Every chemical can potentially the open Pandora's box.

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Tue Sep 24, 2013 6:45 pm
by Prairiepiss
Why not just let the copper still take care of that problem? Instead of adding a bunch of crap?

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Tue Sep 24, 2013 7:00 pm
by MDH
Because a bunch of crap is needed when your still is made from Stainless steel???

It's also worth mentioning you will still have sulfur in distillate regardless, copper provides immediate removal of it so you can work with distillate more quickly and judge your cuts without waiting for two days.

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 6:11 am
by manu de hanoi
MDH wrote:Because a bunch of crap is needed when your still is made from Stainless steel???

It's also worth mentioning you will still have sulfur in distillate regardless, copper provides immediate removal of it so you can work with distillate more quickly and judge your cuts without waiting for two days.
just add scrap pieces of copper in the stainless still on top of the packing

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 6:48 am
by Odin
+1 Manu.

And the effects of copper and sulfurs is more complex. Copper boiler for a strip run or first distillation round actually highers sulfur levels. Gas/copper contact in the first run helps control sulfur levels. I think if I remember a study from the University of Edingburgh well, it is pretty much reversed on the second run.

Odin.

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 10:16 am
by MDH
manu de hanoi wrote:
MDH wrote:Because a bunch of crap is needed when your still is made from Stainless steel???

It's also worth mentioning you will still have sulfur in distillate regardless, copper provides immediate removal of it so you can work with distillate more quickly and judge your cuts without waiting for two days.
just add scrap pieces of copper in the stainless still on top of the packing
Not distilling Vodka, no packing.

Odin that is interesting that a copper boiler results in high sulfur levels during first distillation. I wonder why this would be? The reaction, as far as I know, is that trace soluble copper compounds react with hydrogen sulfide and possibly thiols as well, producing insoluble copper sulfide (CuS and CuS2) that stay within the boiler. Thus, the point of using a soluble copper salt is to ensure such reactions to the entire solution.

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 10:18 am
by Prairiepiss
Toss a copper scrubber in the riser.

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 10:36 am
by manu de hanoi
toss scrap copper on top of a stainless steel scrubber in the riser :)

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 10:37 am
by Prairiepiss
Toss the stainless still and build a copper one. :lol:

Sory manu couldn't help myself. :mrgreen:

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 10:55 am
by MDH
If you'd like to share some lottery winnings with me...

Even in an industrial city/town getting copper is a tough call, I have to order most of it in

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 11:05 am
by Prairiepiss
How much would it cost you to order a couple 100% copper Scrubbers? It would be well worth the try.

Sory I'm just one of those that believes. The less stuff you add to a ferment. The better off you are. And if there is another solution to keep from adding stuff. I use that solution. I just cringe when I see people adding all kinds of stuff to a ferment. If I can't drink it as I'm pouring it into the boiler. I'm not gona make it. Just my two nickles.

Or maybe a better option is to tweek the recipe. So its not a problem in the first place. Just saying.

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 11:07 am
by manu de hanoi
MDH wrote:If you'd like to share some lottery winnings with me...

Even in an industrial city/town getting copper is a tough call, I have to order most of it in
I dont see how copper, from electric wire or whatever could be more expensive than copper+sulfate + vitamin C

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 11:14 am
by MDH
Prairiepiss wrote:How much would it cost you to order a couple 100% copper Scrubbers? It would be well worth the try.

Sory I'm just one of those that believes. The less stuff you add to a ferment. The better off you are. And if there is another solution to keep from adding stuff. I use that solution. I just cringe when I see people adding all kinds of stuff to a ferment. If I can't drink it as I'm pouring it into the boiler. I'm not gona make it. Just my two nickles.

Or maybe a better option is to tweek the recipe. So its not a problem in the first place. Just saying.
The recipe lives by that philosophy, Prairiepiss. It was spontaneously fermented nimrod grapes in a carboy e.g. carbonic maceration. No nutrients, no pH adjusters, survival of the fittest. Even in commercial Pisco etc., sulfur issues are noticeable. When you add fine copper dust to the low wines and distill the product again there is a noticeable improvement.

As for the copper mesh, I can indeed get it easily but shipping costs north of the border are insane so it is definitely more economical for me to use dust.

Copper sulfate and ascorbic acid are not expensive at all. I can buy them in bulk for about next to nothing, a tiny amount of copper dust made from their reaction - less than 1/20th of a teaspoon - is enough to treat a few gallons of low wines. The reason I use powder instead of just scrubbers is because of the surface area that the dust provides. That provides very thorough treatment of sulfur before the second distillation.

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 11:33 am
by Prairiepiss
I had a slight sulfur problem with my mulberry wine. Apparently very common with mulberries. My remedy. I used a copper racking cane to rack it. First racking removed most of it. Second racking removed the remainder. After the third racking I couldn't notice it at all. If I was gona distill it. I wouldn't have bothered. Would have let the still do the work. That's been the only ferment I ever had a problem with.

Re: Don't use CuSO4 to treat Sulfur Issues

Posted: Fri Sep 27, 2013 11:35 am
by MDH
I see... I should clarify that I only add these chemicals to low wines, never to ferments. Kind of like adding a strong base to vodka low wines.