Cleaning stainless equipment

Just wondering how everyone cleans extraction equipment after runs. How often do you clean valves and fittings? How long do you let iso evaporate before putting system back together.

Cleaning is best performed when your done with the item. I like to wash with solvent, and soak in a heated alconox bath. I rinse them with clean reverse osmosis water, and hang on my drying wall.

For my closed loop extractors I use a clean in place procedure. I run the system empty and remove the bottom platter. All of the debris can be easily removed. If you’ve freshly welded anything it pays to passivate the welds before use. You must allow all solvents to fully evaporate before assembling the extractor.


Cleaning should be part of your quality management program, and never an option. I am interested to begin validations on different cleaning techs on SS for the industry. Maybe we can work some out, and test the validity of methods in this thread. Got pesticides in material? (Need methods to decontaminate equip.) Also what makes it tricky for us (as a community of owners of various cannbis equipment) is that most equipment made for our industry is not CIP, (clean in place). I wonder if COP (clean out of place) is the best aproach for users of current available equipments. COP is what most have been doing in essence, but boy would it be nice to have a cleaning cycle in place. @GratefulPhil (IG handle) is a wizard on validated methods (and development thereof). Maybe he can add some color to this picture.


I just flush warm ethanol through the system (acetone if gaskets allow it), and it cleans damn well! Bottom drains are life… I also intentionally buy reactors with tons of fittings all over :wink:
after draining the bulk of ethanol, residuals can be dried under vacuum, and collected with a condenser/cold trap. Heat the jacket if really needed for efficiency.

There are some sweet spray balls that spin while spraying, but they require a lot of pressure behind them.

As far as pesticides, I would likely include lean towards steam and hot water followed by acetone or something. Though it can be a bit cumbersome dealing with all that necessary hot water (depending on scale), without a steam generator or gas-powered water heater. But generally, if Igive it a few minutes under vacuum, but at the atmospheric boiling point of the solvent (not as important to dry residual ethanol in my case, as it may be with other solvents)


Good point with the pesticides, we reject material that tests hot. So that’s a non issue for our equipment. Check out this critical cleaning guide, I use alconox products and I am very satisfyed!
Alconox-Critical-Cleaning-Guide.pdf (2.2 MB)


I like where your head is at!

Check out “PDA Technical Report 29” on google.

A typical cleaning process is clean with acid (one that won’t degrade your SS) clean with a caustic (again don’t ruin your SS) and then rinse with purified water until the conductivity of the outflowing rinse water is near normal.

THEN you must sample the water or swab the equipment and test for contaminants, residual product, etc.

The complexity of cleaning and cleaning validation is something worth finding an expert for. It’s difficult to do it right and document it correctly.


It helps to have “plan b” ready for action though. Any error in data input, record keeping, or analytical methods, and you’d want to be able to efficiently clean the system out and start anew very soon, right?

True enough. Plan b is break every thing down and clean.

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One might find such expert at a brewery quite easily. They clean their stuff all the time and sure love giving tours.


umm, yeah. Looks like I’ve now got a dirty CUP & need to decontaminate it and it’s ancillary equipment. Abamectin. The leadership that apparently directed its application & deliberately failed to document it is no longer on board, but that doesn’t change my problem.

Running 25gal of alconox in 90C water through the entire system CIP style, then 3x or so of fresh water as a rinse is the best I’ve got.

Probably chased with 15gal of iso and more water.

No clue how aggressive I can get with acid/base on stainless.

Pointers would be appreciated.

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You can get pretty aggressive on ss, just not with acids. I would suggest solvent—> hot alconox—>solvent—>distilled water. A solvent dissolved the pesticide, in the first place. Seems like solvent washing would be able to remove the bulk? I would swab the entire thing with a clean etoh soaked rag, then wring the etoh onto a beaker. You can test the etoh for your pesticide to insure it is up to par. I would make sure all your transfer hoses and valves/filters down line are cleaned/replaced as well. Your going to to have to check every cog in the machine!

Agreed. It’s clearly soluble in my solvent. I should start there.

So solvent, 90C alconox, solvent, water.

DI would be great, but I’d be buying it by the gal. I could probably throw together a 5500W 15gal or a 10kW 50gal direct fired still from parts on hand, but I’ll probably just use city water for now. My 26gal and 100gal stills are both heated with hot water from a safe distance :wink:

The 26gal is going to be pressed into service heating up that CIP fluid. Probably push it through the system with 10PSI N2.

Typing “CIP fluid” reminded me how productive heading down to one (or all) of the 1/2 dozen breweries around here to follow @Apothecary36’s suggestion might be. :beers:

Yep, I understand swabs. Had to take them weekly for years as part of lab radiation safety, when DNA sequencing and most hybridization was done using 32P :radioactive:

Also used swabs when tracking down the source of bifenthrin contamination in some of my earliest EtOH extracts.

Turned out to be our AC vents. Previous practice was bug bombs between runs with the AC running “in case the buggers were in there”. Extracts made from leaf tested hot. Fortunately they had not been processing leaf in the 2 years since they had stopped this practice. Extracts made from sugar trim or bud tested clean. Might have been the difference in solvent (probably Butane vs EtOH, it was long ago…). Cleaning the vents and sealing one of the cement floors solved that one, but was an expensive learning experience.

The lab I worked with was working with another producer who managed to acquire their bifenthrin in a AC unit they purchased off craigslist…

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Swissmex Acetone Sprayer, 130 bucks from Jon Don.

Best pressure vessel sanitizer you’ll ever use, especially for those pressure vessels that have openings 6" or smaller.

You can stick the rod in there and pump spray the whole thing down with acetone. Acetone is a powerful solvent that dries quickly, is ultra polar for best pesticide solubility, and that sprayer is built for it so it won’t shit out on you very quickly.


I’ll chime in on limonene as an excellent cleaner for wiped film stills. Our ChemTech engineer suggested a CIP practice of limonene, followed by an IPA rinse, then heat and pump-down. Limonene has better solubility for cannabis oils and residues, it’s way less volatile than acetone (hangs around long enough to get the job done). Probably a bit less flammable…


Well… on the flammability side I can only say that the vapor is highly flammable. I had a rag that was used to wipe up a bunch of limonene catch fire by having a heat gun that was just turned off placed slightly to close too said rag and whoosh flames. Put it out super fast, but holy hell that was not fun.

Ghetto CIP: get yourself a transfer pump and a couple tanks. Fill one with 99 IPA or equivalent, one with 5% H3PO4, one with 5% NaOH. Disconnect the inlet to your first spool and bypass your recovery pump (if applicable). Hook the pump outlet to the top of your first spool and run the line that you disconnected from there into a sufficiently sized tote. Dump your cleaning agent in the tub and pump the system full until it starts running back into the bucket, then keep circulating it for a bit. Depending on what we’re cleaning we generally do IPA>acid>alcojet (non-foaming detergent)>base>3 x rinse. The acid, base, and solvent can be reused for quite a while, dump the detergent every time.

After you’re done, open the system up and let it air dry. After that, close it up, sweep it with dry N2, and then pull vacuum to dry it down.


Hey man - what % Limonene would you add per litre of Water? Thanks!