Light blue oil floating on rum tails

[I8ian4t]

Hi guys. I have been working overtime Getting some macrum on oak.
A few batches I went too deep into the tails. Nice and cloudy.

The next day I noticed some light blue floating oil?. I didn't think much of it.
Soaked 90% of it off on a clean cotton rag. Less then enough to cover 1/10th of a teaspoon.
The spirit wasn't blue. But very cloudy

Any ideas what it was? I have since done a spirit run. no signs of blue or oil, it has been on oak since early November, starting too smell fantastic.
Is it safe too drink? I have 4 Demi's and and an feints run that has taken me a lot of time.

It would break me tipping it down the sink

Thanks again

[db1979]

I've had this too. Not with rum though (since I've never done a rum). It'll just be a component of the tails that isn't soluble with the rest of the mixture that's in that particular cuts jar at room temperature. It would have been soluble in the boiler and in the fermenter though but running through the still changes things.

The blue colour I think has to do with how light refracts at different boundaries, the boundaries between the oil and air, the water/ethanol and oil etc. Colour can also be caused by complex organic molecules or metal ions, both of which I doubt would be the cause.

Is it safe to drink? I wouldn't separate the oil and drink it. But the rest of your product should be fine. You drink all of it in beer or wine anyway. Many go deliberately into tails looking for particular oils for the flavours they give when aged. It's a real art.

[db1979]

And just because you don't see the blue on other runs doesn't mean you don't have oils in the tails, it's just that they haven't become insoluble. When dissolved there is no phase boundary and the light passing through doesn't refract.

[I8ian4t]

I might need to go back to school. :)

When i soaked the oil up on a white cloth. It was light in colour but bright blue. It wasn't a slick over the whole surface.. More like a textured blob.

I'm 99% sure it was late in the tails. (I was trying to get as much flavor as possible for a stinky rum) But have no idea where the blue has come from. Could this still be "how the light refracts at different boundaries"

[bluc]

Whats the still made from? Copper?

[Sam.]

My money would be on dirty copper :-B

[coffe addict]

Acidic nature of tails stripping copper sulphate off. Would be my guess.

[Sam.]

Acidic nature of tails stripping copper sulphate off. Would be my guess.

:text-+1: A bit more precise than my explanation :handgestures-thumbupleft:

[prawnz]

Acidic nature of tails stripping copper sulphate off. Would be my guess.

Interesting , so would it be correct to assume that if your copper is clean going into a run , there would be no copper sulphate to come off ?

Or is it something thats created during a run as well ?

[db1979]

bright blue. It wasn't a slick over the whole surface.. More like a textured blob

Copper sulfate would be either an insoluble precipitate, or soluble in those conditions (should be soluble at low abv). It would not form a blob on the surface. It would sink. You wouldn't be able to scrim it off the top. Only organic substances (such as oils) would float.

I wouldn't describe what I've seen as bright blue though. But I am colourblind.

[db1979]

Also, you need a heap of copper coming off your still (as copper sulfate) in order for it to be remotely visible as a blue colour. So much that our stills would be falling apart on us after a few years.

[coffe addict]

What I've experienced is quite bright blue it's usually only if I haven't done a run for ages.
It has been held with the oils from tails and after being left in a jar for a while in the cupboard it drops to the bottom. I notice it in the liquid but quite faint compared to on the surface. It also has the tendency to group together on the surface but I've not seen what I'd describe as a blob more like a thin layer.

Most of my still is second hand copper and it's surface was caked with a blue/green substance that had to be cleaned up before I could start. I had a pile of scrapings on the floor but not a single noticeable effect on the copper itself. I suspect that it's kind of like rust in the way metal oxidises and before much less dense and therefore appear to be alot more volume than the original metal did.

[I8ian4t]

It's all clear now. With no floaters and smells ok?
Safe too say it's fine?

[coffe addict]

With out a pic it's hard to know what caused it.
It may not have been copper in the first place. What I had definitely was and I re-ran it.

[coffe addict]

As it's cleared There's a good chance that you just went too deep into tails. With the copper sulphate it settles out on the bottom with time.
Are you collecting in small jars and airing for a day before doing cuts?
As that practice usually ensures that tails don't end up in the keep jars.

[I8ian4t]

It was in the stripping run. I take the lot and dump it all together for a spirit run.. in hind sight i should have binned the 'blue' lot as it was only 2-3L of 40~%. But i dont want too tip 20L of oaking 60% down the sink.

On a spirit run i collect in smaller jars and let it sit over night :)

[bluc]

Sounds like copper from the still but spirit run normally clears it up. The fact there was a blue blob has me a bit puzzled also..

[coffe addict]

Copper sulphate won't carry through the upward side of the still and as you've just cleaned out the downward side just run your spirit run as normal...
Chuck it all in it'll be fine.

[Zak Griffin]

Oil and floaties are all fairly standard signs of deep tails, from my experience... Especially with rum.

[Dig Brinker]

I had that last rum strip. One of the last jars collected, very oily , cloudy, definite tails. If I recall correctly I left the cut jars for 4-5 days before sorting. It wasn’t there fresh from the still. Strained through paper & added to spirit run. On the paper it was gelatinous, like a bright blue blob.

My still was definitely dirty when I ran it...