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Cleaning the copper still with citric acid solution, frequency


DistillateurQc

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I clean with PBW between runs, and with acid whenever the copper gets dark and looks like it needs a refresh. Last time i ordered chemical they were out of PBW so i bought bru r ez which cleans better than PBW but also gives off slighty harsh fumes when mixing. It is non caustic, and I called Birko before ordering and they said it was fine for copper.

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17 hours ago, SlickFloss said:

Please tell me you are not cleaning a copper pot still with Caustic. If there are any copper elements of your still (which there should be) those are being removed pre caustic, correct?

low concentration caustic solution, about 2%.

How do you clean your copper still?

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Yeah caustic will pit your copper and fuck it up. So will PAA so I'd reccomend you avoid that as well. A lot of people design steel kettles that they will CIP and then removable copper parts that can be COP'd but of course this all depends on your size and scale for feasability. We will use brewers wash (PBW, Bru EZ) etc if we have tons of soil on a copper kettle but for the most part: using enough water in mashing, using the correct texture of ground grain that features a low ash content and has been well screened, running the still appropriately and agitating the whole time usually keep heavy soils from scorching. If that is the case, copper pot can be easily cleaned with low concentration citric. We have four stills here (headframe, CARL pot still ~2200 liters, CARL Stripping column 25 inch diameter, and S.M. pot still 240 gallon) with a large vendome on the way. Briefly, here is how we clean them all, minus the Vendome, if you'd like me to expand on anything please let me know:

-Head Frame

CIP'd with Caustic/Acid wash cycles every 25k-40k gallons depending on the production schedule [what we've done and what we have coming], it''s behavior, and spirit quality etc. We do not have spirit type changes on here very often, but we would clean in between spirit changes if we did, we also clean between lots. 

 -CARL pot still

At the moment this still is currently used only for Gin redistillations. It is capable of making GNS from grain in a single pass, so when we do hook it up for that functionality we will look at utilizing PBW in the kettle when we need to, but if its anything like our small pot we would probably be able to get away with out it and just using hot citric. We turn this over after every single run for gin given how delicate and fickle gin can be, so that's cleaned daily.

-CARL stripping Column. 

Run Caustic CIP through the bottom four plate sections and sump (which are all stainless steel), fifth plate section is copper and depgh at top is stainless. This column feeds mash and fruit macerate to the fourth plate column, so the top plate section and depgh only ever touch vapor unless something goes really wrong. These sections are isolated for CIP with acid only. We clean in-between lots, spirit type changes, and when necessary, usually every 40-100k gallons. (We've heavily modified this thing into a beast. Do not purchase a carl stripping column, the only other one I know of in the country is mothballed unless the company is back up and running. Our identical units do not run even remotely the same, I have ran them both. 

SM pot still (100% copper still)

This one is a biscuit and a half to clean. So kettle soil we can clean with hot acid and it works for the still heads too (SM platform is interchangeable heads), but the Lyne Arm (which is all copper) and the condenser (all copper) get really jacked up from normal runs. Especially with the amount of runs we as roll on a week. Lyne Arm is removed every run so its not just spewing hot vapor water into the condenser to get it all sky blued up. Word for the wise, unless its a a hell of a deal at auction, you do not want to be running a commercial operation with 100% copper stills. Any Lyne arms on a descending angle to a condenser and condensers should all be stainless. We backfill our copper condenser with hot citric, and flush it clean. If kettle isn't soiled and coked up we will rinse and run full lots/production runs in between full cleans. If we are stripping 4-5 runs on this thing of the same type we will just rinse and run. We do full cleans between lots, product type changes, stripping runs and finishing runs, etc.

 

Rinse and Run: Rinse with water, pressure wash if we have to

Full Clean for Copper: 

Cool rinse Spray water

Cool Rinse recirculated water 

Hot Wash recirculated Acid

Hot rinse spray

cool rinse recirculated

-0R-

Cool rinse Spray water

Cool Rinse recirculated water 

Hot Wash recirculated PBW

Hot Rinse Spray water

Cool Rinse Recirculated water

Hot Wash recirculated Acid

Hot rinse spray

cool rinse recirculated

 

Full Clean for Stainless:

Rinse (spray, then recirculate water)

Hot Wash Caustic* (recirculate)

Rinse (Spray, recirculate)

Hot Wash Acid (recirculate)

Rinse (Spray, recirculate)

Remember, if you're slicker than shit and know your conductivities you can reuse Caustic way way way way wayyyyyy past what you think you can. I wouldn't attempt unless you're firm on the chemistry

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