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Cleaning a new still

Posted: Thu May 27, 2010 2:43 pm
by kiwistiller
How do I clean my new still?
This one has been cropping up quite often recently. When you build a still, it will generally result in some rather dirty metal. There will be a lot of oxidised crap all over it, as well as flux, etc. To deal with this and make it safe, we perform a 'cleaning run' (or sometimes two). There is no 'right' way to make sure a still is clean, this is just one option that I've written up to clear up some confusion. I'll only talk about the inside of the still, and I'll leave Olddog to tell you how to make the outside shine if you're so inclined (optional extra, but damn his stills look good). This guide will attempt to err WAY on the side of caution, and detail a very thorough cleaning process. Obviously, it's going to be a little on the vague side, considering the differences in stills you could build.

1 - Soak and Scrub
A really good way to start is to soak any parts small enough in a weak acid solution - I'd use dilute vinegar, which we can reuse for the next step. soak it for a good few hours, or overnight. This is really an optional step, but is a nice idea for things like coils. You can augment it by giving the insides a bit of a scrub as well with a kitchen scourer (don't use your packing for this :lol: ). Keep the vinegar solution.

2 - Vinegar Cleaning Run
Next, chuck the vinegar solution into your boiler, attach the still head, and fire it up. I personally like the idea of blasting the still and condenser with acidic steam - the problem if you don't run steam through it is that some areas (like the top of a liebig condenser) may be untouched in normal, condenser-on operation. Of course, as we're only boiling a vinegar and water charge, there is no fire danger - but there is still vapour being generated, so this is a good time to double check that your still is always open at some point to the atmosphere. Of course, normal caution is needed with hot steam, don't scald yourself. If your column has packing, it isn't necessary to have it in at this stage.

Special consideration for VM: you might struggle to get steam out the takeoff. If this is the case, check your valve is open, then roughly cap your still, check again that your valve is open, then check a third time - this is because we're breaking the cardinal rule here, if the valve was shut, the still could build pressure. When I had to roughly cap my VM (for this purpose), I got an offcut of 4x2, and made a circle of dough paste, and sat it on top - this was enough, it doesn't need to be perfect.

After steaming it for 20 minutes or so, turn on the condenser(s), pour water into the worm bucket, whatever it is that will return your still to normal condensing operation. Check that the condenser is knocking down vapour. A reflux condenser may struggle to knock down this vapour, don't worry about that at this stage, it's a lot easier to condense ethanol / water mix. Run with the condenser(s) on for 20 minutes or so. This is a really good time to get a (glass!) mirror, and check for vapour leaks in any seals and solder joins, brazing, etc... The mirror will fog up if held up to a leak.

Shut down and ditch your vinegar.

Give everything a comprehensive rinse out with water. Most of your still should be pretty shiny on the inside by now. If there are visual patches of flux and crap still in there, go back and do some more soaking and scrubbing before you continue.

3 - Ethanol Cleaning Run
To be completely thorough, we should do an alcohol cleaning run as well. Use any old wash, pretty much whatever you can make the cheapest and easiest. Alternatively, you could chuck in some cheap box wine or something (avoid beer - hard to get the hop oils out afterwards), pretty much any source of ethanol you like. DO NOT use denatured alcohol for this (never put that through your still).

This second cleaning run can double as a practice of still operation. If it's a reflux head, you can put the packing in for this one. Do not repeat the steaming step we did with the vinegar run, as the ethanol vapour is of course flammable, and heavy. Just run the wash in the normal fashion for your design, and have a play around with heat / cooling to get the hang of it. See how the ABV changes. If it's a reflux, play around with the reflux management, see how things respond to your actions. You get the idea.

Don't treat this as drinkable, but do keep it, clearly labeled as cleaning run alcohol - you can use this for your next build. Trust me, there'll be others :lol: :lol:

Right, that's it, the three step process to ensure you have a safely clean still to begin your hobby with :D

Re: Cleaning a new still

Posted: Thu Aug 19, 2010 10:29 pm
by olddog
Cleaning / polishing the outside of a new still

When you look at pictures of stills in commercial distilleries, we all ooh and arrh at the bright shiney copper, so why when investing a few hundred dollars in your still build, would you want to leave your still looking like something from the scrap yard, when with a bit of care and effort, you can get it looking good.

When I start a build, I consider which piece goes where, if there is a piece that will be difficult to clean and polish after I assemble the still, I will clean and polish it before soldering, then after soldering all it needs is a light hand clean to remove the torch/flux burn.
When I start to solder, I only put enough solder to flood the joint, any more will just run down inside the joint. If I get a bit of a blob on the joint, I reheat the blob and with a hogshair brush I brush off the surplus solder while it is still in its molten state, be carefull when doing this, if you flick any onto yourself you WILL get a serious burn. After removing the surplus solder, you wil be left with a thin film of solder left on the copper, this can be removed with a block of wood and some 400 grit emery cloth, to leave a nice clean joint.

After assembly is complete I use some medium grade wire wool to clean the whole surface and remove all torch flares and burnt flux. Once this has been done, repeat using fine grade wire wool. I then use my bench grinder, which I have removed one of the grinding wheels and replaced it with a buffing wheel, to polish the surface to a gloss finish. If you do not have a buffing wheel, you can use some automotive cutting compound to polish the surface, but a buffing wheel is a bit more thorough when trying to remove any scratchmarks.

Once you are satisfied, and happy with the stills appearance, you can give the still a coat of copper laquer, which will stop any oxidisation. All you need to do after a run is to just wash the still in plain water and then dry with a cloth to maintain its appearance.
Even though a still has been laquered, its colour will change to a darker colour with heat, but will not oxidise, if you prefer not to laquer, then just give the still a polish with some brass polish regularly.


Re: Cleaning a new still

Posted: Sat Sep 25, 2010 3:44 pm
by rubber duck
A member here was recently doing a vinegar cleaning run on a new still. As this member was loading the boiler with vinegar they added a pint of heads from a previous distillation run. Apparently the still had a leak or there was steam escaping from the condenser output as there should be during a vinegar cleaning run. Because of the heads addition the steam was flammable and a small fire occurred. This could have resulted in a disaster, luckily our friend was paying attention as one should in a hobby of this nature and had water and a fire extinguisher on hand.


During the first vinegar cleaning run not only is the still being cleaned,(steam is exiting the product output) but the operator is also double checking for leaks.

Re: Cleaning a new still

Posted: Sat Aug 31, 2019 4:50 pm
by WithOrWithoutU2
Is a 50/50 vinegar and water solution recommended or a different percentage mix?

Re: Cleaning a new still

Posted: Thu Apr 23, 2020 9:33 am
by Bugdave63
I find lemon juice & 000 steel wool works wonders for a copper still that has not been sealed with a coating, just the bought stuff from a supermarket.

Re: Cleaning a new still

Posted: Wed Sep 16, 2020 9:10 pm
by Desert Dweller
When cleaning with citric acid, what is the recommended citric acid concentration? 30 grams/litre?

Re: Cleaning a new still

Posted: Thu Sep 17, 2020 5:29 am
by Yummyrum
That would work . Couple of teaspoons in a litre . :thumbup:

The more you use , the quicker the clean .

Personally I’m a Sulfuric acid user ...perhaps I’m also an impatient bastard . I like to get the job done quick . I add 200mls concentrated Sulfuric to 800mls water .

Talking 15-20 minates soaking in Sulfuric verses about 24-36 hrs in citric .

Note : Acid soaking is different approach to Vinegar steaming runs . Acid soaking requires the ability to physically scrub after soaking .
IE , I might acid soak say a copper column , but I would then follow it up with a good rinse in water and then shove a scrubber on a stick through it a few times to knock off the crud ... then rinse again.

I do a lot of this type of cleaning when building stills . One advantage is that it makes damn sure each part is spotlessly clean , free of oxide buildup , and helps with the soldering process .