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Hello!

I have the first aliquot of a series of stripping runs of apple brandy (~2.5 gal.) that came across with a pronounced yellowish/greenish color... see photo.

I am using a solid copper Alembic pot still, and had first run an 8 gal. 50/50 vinegar/H2O cleansing run to completion followed by a second straight R.O. H2O run for rinse, then this is what I got when running my first aliquot of fermented apple must... This was the 2nd batch of apple brandy made with this still... cleaned the very same way when received new and never any color in the distillate... No further color was observed in subsequent runs.  I'm thinking this is most likely NOT an oxidation state of CuSO4 (H2O) because of the absence of the distinctive sulfide odor... wondering what it might be, and wondering if it is possible to save the strip by re-distillation.

Any comments are welcome... Thanks!

 

 

Green.jpg

Edited by A.S. Burkett
correction

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I might mention that there is NO odor that would typically signify a sulfide... e.g., rotten eggs, sulfur... only the clean sweet aroma of apples.

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To Silk City Distillers... No... not to my knowledge... it was a stripping run, so I ran it kinda fast... but no puking was observed... and I ran all subsequent stripping runs at the same temp/speed and from the same batch of must with no carry over color after this first run.

Thank you for your response.

Edited by A.S. Burkett
acknowledgement to reply

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Though none was observed... I am really tempted to go with Silk City Distillers question re "Still Puke?"... and say maybe... or perhaps... possibly a slight scorch due to too high of heat... but again re the possibility of scorch... no noticeable odor.

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Scorching would be very obvious in the flavor, and it wouldn't cause the coloration in the distillate.

The puking needn't be obvious, if there was foaming in the still, that would probably be enough to carry over into the distillate on a fast/hard strip.

If you are just stripping bulk cider in smaller batches, just add it back into your next stripping run.

 

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If you are concerned about copper reactions and copper in your distillate, you could also consider replacing everything after the apex of the vapor path with stainless.  Copper Up - Stainless Down.

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we ran a test batch of 100percent wheat mash , the mash turned out great tried stripping it with direct heat and it scorched and looked jus like your sample very little smell in the distillate but very noticeable in the backset and in the empty boiler . even tho it was lautered there was enough fine flour in suspension to burn and discolour the product .     

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Many thanks to all who offered their insights on my quandary... Being relatively convinced by Silk City Distillers'  that my problem lie in an unobserved still puke, the discolored strip was added to three subsequent aliquots of strip and re-distilled to the 1st spirit run... no coloration was observed in the resulting distillate... neither in the fore-shots nor bulk run product.

 

Again, Thank you all!

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Oh... and as an added measure I intend to reserve a sample of the leftover pot liquor and as well a sampling of the product for a NaOH test.

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I am in agreement with Silk City that some foam over early in the run is a possible cause.

I have never used vinegar to clean but it would not surprise me at all if the vinegar reacted with the copper to give the greenish tinge, especially if it was some time since the cleaning.

Was this the very first run with a new still?

Could be weathering products on the copper, or weld byproducts, that apple spirit was better at stripping off than vinegar was.

If not new what was the previous run? Apple spirit may have been better at stripping leftovers off than vinegar was.

If there is any moisture left in my still it often drips blue or green from the condenser the next day, and I can be sure that the start of the next stripping run will be a greenish brown colour. It is just at the start of the wash run so it really doesn't matter as the spirit run will fix it.

It would be interesting to understand the chemistry of what was happening but in the end if the spirit tastes and smells great then it is unlikely to be of concern.

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Thanks for the reply PeteB... Wanted to respond to your reply and questions posed... so the best way is just to paste your full reply and insert my comments... here goes... :-)

 

I am in agreement with Silk City that some foam over early in the run is a possible cause.  So am I also in agreement... especially so since the re-distillation removed the color.

I have never used vinegar to clean but it would not surprise me at all if the vinegar reacted with the copper to give the greenish tinge... Vinegar is what I have always used, cheap, effective and safe, especially if it was some time since the cleaning.

Was this the very first run with a new still? No... ran a cleaning run with vinegar when still was new... no color was imparted... and ran 96 gal of apple must just for stripping runs followed by double distillation (2x spirit) mid-April to early May... the still sat unused until end of June when I started the next stripping... but performed another cleaning run with vinegar and a rinse run with R.O. H2O prior to the first (and only) stripping run that color was observed.

Could be weathering products on the copper, or weld byproducts, that apple spirit was better at stripping off than vinegar was. Not likely given the manner of cleaning prior was the exactly the same as previous batch.... we're back to the likelihood of a still puke

If not new what was the previous run? Apple spirit may have been better at stripping leftovers off than vinegar was.  Previous run was Apple.

If there is any moisture left in my still it often drips blue or green from the condenser the next day, and I can be sure that the start of the next stripping run will be a greenish brown colour. It is just at the start of the wash run so it really doesn't matter as the spirit run will fix it.  I've observed that as well between consecutive runs when the still was left empty but wet overnight... this time the still had sat unused for ~1.5 months... it was bone dry before I performed the cleaning and rinse.

It would be interesting to understand the chemistry of what was happening but in the end if the spirit tastes and smells great then it is unlikely to be of concern.  I agree!  :-)

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Don't use vinegar, use citric acid for cleaning. Don't clean by distilling, just soak or flush with weak hot solution. Distilling vinegar in copper creates copper acetate, nasty. And, if you have any vinegar (acetic acid) in the apple cider, that might come across as copper acetate. As pointed out by others, you will have to get rid of copper downstream of still head to eliminate that, or make sure the copper is completely passivated downstream.

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