Do large scale Ethanol Extractors use copper condensers or just stainless steel?


your still builder does understand the thermal transfer properties of those two metals.


having decided that you’d prefer stainless, the trick is then to change some of the other variables in the equation. eg the ΔT , heat exchanger surface area, or flow rate.

@TheGratefulPhil was kind enough to work some of that math

edit: and thanks for bringing this up. I was aware that copper was more efficient, but was unaware of the magnitude of the difference. check the tiny condensers on the first still I built.


Do I really have to go with stainless just on the condensing coils or can I have the condensing coils copper and everything else Stainless and still be fine?


This unit will be used for distilling ethanol out of the oil It is only a reclaim still so technically the cannabinoids in the oil which is left in the still will never pass through the Copper except for Turpines


@Champone I think cyclopath summed it up great here.

The problem isn’t the cannabinoids touching the copper, but rather what the compounds that will distill off with the etoh from the concentrate will do to the copper, possibly contaminating your ethanol and subsequently contaminating your extract that you re-use that ethanol for. I have had the misfortune of ending up with blue etoh when running a mash for my own personal vodka when I simply added baking soda to the wash in an attempt to achieve a more neutral spirit. Neither the baking soda nor the fermented wash touched the copper, but there was a reaction between the yeast nutrient I used and the baking soda which formed compounds that created copper salts, which then ended up in my ethanol. Copper salts being as toxic as they are, I decided to just scrap the ethanol and do a laborious break-down and cleaning of my still rather than try to clean up poisoned product. I have had the same blue ethanol problem when I try running too far into the tails, which probably means it is something with a higher boiling point than ethanol that co-distills that is pretty rough on copper. I wonder if that’s also what was causing the blue in cyclopath’s experience?

You can probably get away with using a copper condenser if you just distill off enough ethanol to move the product into a rotovap for finishing. Cyclopath stated that he didn’t have any issues with the color of his ethanol until he tried squeezing out the last of it from the extract. Hell, I use a copper reflux tower to re-proof my reclaim and I have had zero issues. But if I was going to invest the money into it myself, I’d rather just do it right the first time instead of having more expensive issues down the line.


I usually still it down to the last 10% then finish off in a roto. So I would be ok with copper?


I agree with doing it right the first time. My entire still is stainless except for the coil inside


depends what you mean by “coil inside”.
you using something like this?



We run Ethanol only and use stainless steel for everything.


It’s a bobkabob Condenser that’s the only part that is copper all the rest is stainless


Do you run your still under vacuum


hmmm…wonder what a bobkabob is…

first link I clicked on. and it’s stainless!


Too many :honeybee:s in my spelling I was driving ha. Then why’s my damn builder saying I have to use copper lol? I wonder if it’s because I’ll be under vacuum therefore needing a much lower temp to cool


Do you think just bring copper on that part is a no go ? Or it could work only distilling down to the last 10%?


How are you planning to run a boka under vacuum? My column is a boka and I’d love to be able to run it under vacuum, but being LM I figured it wouldn’t be possible to have any takeoff while running, which would make it inoperable.


You have a catch can.


possibly. maybe even probably. I’ve certainly posted pictures here showing the copper condensers on my early stills.

however, after seeing vivid blue recovered solvent on more than one occasion, I am sticking with stainless.


Fucking brilliant. Do you attach a vacuum line to the top of the column as well? Where the vent hole usually sits.


Do another bend then attach


So hard no? My solvent will be fucked ? Even if I leave 10%?


not at all what I was trying to communicate.

my experience says that if you’re recovering the last of the solvent with a rotovap, you’ll probably be fine. which is a definite maybe, not a hard no.

however, having not been fine on more than one occasion, when specifically trying to get the last of my solvent off biomass, I personally am sticking with stainless.

I’ve seen first hand that copper can react with (something in) my solvent (sometimes). I’d prefer not to have to worry about it (ever).