Blue residue in gin?

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papstoker
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Blue residue in gin?

Post by papstoker »

Morning all. I have made gin twice, using a ginning bag and some experimentation with the botanicals (hint - a few months' rest does wonders). Easy and delicious.

My second batch is nearly finished. I was inspecting the last bottle yesterday and noticed a blue residue that had settled out at the bottom. I also then noticed a similar residue in a jar of heads I had kept in the fridge from one of my fjrst distillations in 2016.

Now I am slightly concerned (not enough to stop sipping the gin!) Is this some kind of fungal infection? Or just botanicals and oils settling out? I'd hate to kill off someone with some kind of home grown mycotoxin.

Or maybe its something to do with my copper still? I met another stiller a while ago that was warning me against copper and claimed that stainless steel is much better. He was talking bosh on some other issues so I didnt take him too serious.

Your thoughts?
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Saltbush Bill
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Re: Blue residue in gin?

Post by Saltbush Bill »

No real answers to the problem at the moment .....but may I ask why you keep your heads in the fridge ?
papstoker wrote:I met another stiller a while ago that was warning me against copper and claimed that stainless steel is much better. He was talking bosh on some other issues so I didnt take him too serious.
I wouldn't listen to him at all , but that's just my opinion.
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fizzix
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Re: Blue residue in gin?

Post by fizzix »

There's been a lot written about blue distillate. Check your still interior for blue deposits and/or do a cleaning run if there's more evidence.
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Re: Blue residue in gin?

Post by Shine0n »

I've gotten blue flecks after my still sat idle for a good spell, the stuff a ran was solely as a new cleaning run and I also ran just water to flush the rest out. It worked and now it's back to normal.

What I do now is when I'm finished with running, I'll break it down, rinse with fresh water, let it dry or use compressed air and put balled up rags in the ends to keep air out of each section.

No more problems even after 3 months of sitting, although I still rinse it out just because.
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Re: Blue residue in gin?

Post by kiwi Bruce »

Describe what you mean by "residue" Is this a sludge or crystals or colored liquid under the spirit ? You are correct on calling BS on the copper v SS issue for still building, copper is the metal of choice and has been for hundreds of years. Copper is a metal that needs to be "Passivated" if your still is new or it's not been used for a while. This just means a quick rinse in a food grade acid like citric. If it's not passivated, the copper can react with an ammonia source for the wash (DAP) or even your brewing water. If it's in your drinking stash re-distill it.
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Re: Blue residue in gin?

Post by HDNB »

if its a sediment when cold but goes back into solution warmer i'd suspect lipids, fats, oils from plant matter

fluffy white/blue snowflake looking?
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Re: Blue residue in gin?

Post by papstoker »

Thanks for the comments guys. I dont really suspect the still, or copper, since I have made many other types of runs since and before and they are all crystal clear.

Kiwi. With blue 'residue' I mean a faint blueish sediment that formed at the bottom of the bottle of gin after about 2 months of rest. It was effectively tripple distilled (poststil, sugar and rice washes, stripped, mixed and redistilled and then 'ginning bag' distilled) The more I think about it, the more I susoect the botanicals, or oils or lipids. The taste is delicious though.

I have been thinking - why is Bombay sapphire shipped in a blue bottle, and I have even seen some gins coloured blue - maybe to mask a blue sediment?

Has anyone ever encountered a fungus that can grow in 40% plus abv?
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kiwi Bruce
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Re: Blue residue in gin?

Post by kiwi Bruce »

papstoker wrote:Has anyone ever encountered a fungus that can grow in 40% plus abv?
I think I'm correct here, but I'm not quoting the rum-runners here on HD (They have wild dunder buckets and pits and pots, full of the most awful infections imaginable) ...but I don't think there are any wild yeasts or other fungi, other than brewing yeast, that can survive in anything above 11 or 12 abv and it might be MUCH lower.
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Re: Blue residue in gin?

Post by Kareltje »

The very first gin I made, I had macerated at about 90 %ABV, and then diluted it. I ran it up to more than 100 dgr C and there appeared a thin, resinlike, blue-green film on top of the last tails. It floated on the very last tails, but maybe it sinks in high proof heads?

I have read of some micro-organisms living in kerosine and blocking fuel feed systems in airplanes. Causing them to crash, even. But I suspect they grew in small waterdroplets in the tanks.
Nothing survives 40 %ABV and even less survives distilling.

But maybe the blue originates in the copper. As is already stated: there is a lot said about that blue hinge.
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Re: Blue residue in gin?

Post by thecroweater »

My guess is HDNB nailed it, naturally just a guess without eyes on it. Folks are oft quick to jump to copper salts, yeah sometimes a real Krusty column will deposit that in ya early fore shots but my experience is that's about it, jelly fish ain't copper.
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Re: Blue residue in gin?

Post by papstoker »

Thanks for the ideas gents. I'm leaning toward the botanical oils idea. My still hasn't given off and blue in any other runs. Relieved that there aren't nastues that can grow in 40%+ alcohol, although I have heard of extremophiles that can grow in diesel tanks.
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Re: Blue residue in gin?

Post by butterpants »

Are there any chopped up smurfs in your wash?
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Re: Blue residue in gin?

Post by still_stirrin »

butterpants wrote:Are there any chopped up smurfs in your wash?
Or maybe a Smurf “dipped his finger” in the stream as it was running. You know how lovely that fresh juniper smells coming out the spout...tempting. :lol:
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Re: Blue residue in gin?

Post by Alchemist75 »

It's the heavy, resinous oils of the juniper, in sufficient concentration they flocculate and fall out of solution as a bluish mass. I'd either use less juniper or mind the cuts better, that should fix it.
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Re: Blue residue in gin?

Post by Pikey »

Alchemist75 wrote:It's the heavy, resinous oils of the juniper, in sufficient concentration they flocculate and fall out of solution as a bluish mass. I'd either use less juniper or mind the cuts better, that should fix it.
I didn't know that - but your input is usually good - so I'll go with it. 8)

There is a thing called "Diesel bug" which grows as a jelly like mass in old diesel tanks, clogs filters and stops engines - I had it on the boat last year - I believe it's a bacteria (not blue tho' afaik)

The only blue I know of is Copper Sulphate - poisonous - but quite How poisionous I don't know. I have had blue deposits on uncleaned still pipe, which came over, but nowadays I pull a stainless scruubie through the tubes and a quick water wash.

If you're unsure, Citric acid soak for a few hours will bring copper up spotless - just needing a rinse. Vinegar would probably do it, but I can't bring myself to let vinegar anywhere near a ferment - not even in a container, in the same room !

[Edit = same as the others - I'd use copper over stainless any time ! :thumbup: ]

Do let us know when you work it out or post a photo would be good :)
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Re: Blue residue in gin?

Post by Alchemist75 »

Yeah, I've observed it making compound gin where you have full concentration of juniper distillates because no cuts are made. I've seen copper contamination before but it usually presents as a brownish film floating on top of the spirit or a dark deposit left behind in the boiler after the spirit run. If it's blue then it's probably a basic salt as opposed to the brownish sulphide. I now do my spirit runs without copper to eliminate all possibility of copper contamination. Basically if you heat up vinegar and salt that will clean out copper works like a charm and you should get little copper contamination. Do it in between each run to ensure purity.

Interestingly, if you add chlorophyll to a gin it will cause the juniper oil precipitation to occur more completely and quickly. It's possible to put the mixture in a sep funnel, allow it to settle and then drain the resins off. The end product will be clarified and a lovely light green as well as a lighter flavor. Using zeolite might do the trick too
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Re: Blue residue in gin?

Post by Pikey »

Copper Sulphate - https://en.wikipedia.org/wiki/Copper(II)_sulfate

Lovely colour when dissolved - only "Blue" I know.
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Re: Blue residue in gin?

Post by papstoker »

Thanks Pikey - It could be.

I am not a chemist, bI understand copper sulphate is very hydrophilic, and turns transparent when allowed to absorb water - baking it turns it blue again. Just speculating.

Furtunately I have not seen the blue again.
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Re: Blue residue in gin?

Post by Pikey »

papstoker wrote:Thanks Pikey - It could be.

I am not a chemist, bI understand copper sulphate is very hydrophilic, and turns transparent when allowed to absorb water - baking it turns it blue again. Just speculating.
No it is a lovely blue solution - but not likely to be present in great amounts, so may just appear as a feint tinge.
papstoker wrote:Furtunately I have not seen the blue again.
No - It would be washed out of teh still fairly quickly and not return, without the apparatus being stored in damp and unwashed conditions.

I just give my kit a quick rinse after a visual inspection and as I said pulling something through the vapour path nowadays, before use.
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Re: Blue residue in gin?

Post by kiwi Bruce »

Pikey wrote:Lovely colour when dissolved - only "Blue" I know.
Silver Amines have a very intense blue...the silver salts can be moved back and forth from solid to a liquid with hydrochloric acid and ammonia to remove impurities when refining the metal. Silver chloride is only very slightly soluble in water and forms a thick white mat almost like cottage cheese, but it dissolves readily in ammonia to form a beautiful blue liquid...we are all using silver/tin solders now, I don't think that the silver can leach out of the solder...but I don't know for sure.
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