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Black oily residue after distillation run


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Hi all, I am running a 100 percent corn in an electric bain marie. I have noticed a black oily residue after a stripping run. I keep finding in different places. I use PBW and Citric and I still seem to be getting spots of it especially in the parrot.  Any idea what it is and if its normal?

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15 hours ago, rickthenewb said:

Hi all, I am running a 100 percent corn in an electric bain marie. I have noticed a black oily residue after a stripping run. I keep finding in different places. I use PBW and Citric and I still seem to be getting spots of it especially in the parrot.  Any idea what it is and if its normal?

It is not normal. You should check to be sure there are no inappropriate gaskets in the high proof steam path from the still. For example, black EPDM will sometimes leach out at high proof, high temperature. We had to replace all of the black EPDM in our still in that path for that reason. Typically, don't see this on the strips, more likely on a spirit run. It will also impart a bitter taste to the spirit.

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I've seen this with a copper condenser and all corn mash on stripping runs. Do you have copper in your distillate path? Is it real thick and hard to clean off your hand? Smell real bad?

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I have a cooper head but other than that its all stainless. The stripping runs smell like corn and alcohol and has a slight haze that I am attributing to the heavy tails.  This is going to be gns for our vodka so I hope whatever it us works it's way out, any thoughts on it?

Yes, it comes off black and smells bad.

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Sorry @bluestar .  EPDM is the solution and is the best to use.   Ensure that you have food-grade EPDM.

 

I suspect that Nitryle / NBR has been used coupled with a possible Chinese supply which at best is dubious.

 

Try select reputable supplier options e.g. Kieselmann etc.

 

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EPDM … (ethylene-propylene diene monomer).   Yes, the gasket material between the clamped tri-clover ferrules.

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