Putting older posts here. Going to try to keep the novice forum pruned about 90 days work. The 'good' old stuff is going to be put into appropriate forums.
%^&*% - firstly my apologies, the forum search demands that words are at least 3 letters long - so a search under this topic was not successful.
So ...
I'm about ready for a cleaning run on my VM still. I have a 50mm column that is 1.7 metres high. On top is a cooling coil and just below this is a horizontal takeoff to a gate valve with a liebig condensor that is 1 metre long.
If I understand the principles of VM right, then only the alcohol (ethanol plus some of the lower temp components) from a normal run will find its way down the liebig. As I want to do a water and white vinegar run, I suspect this would not clean the liebig part.
Is it appropriate to put a rag plug in the top of the column providing the gate valve is open and thereby forcing the mix down the liebig?
What kind of ratio of vinegar to water should I use?
Yeah, just plug the top with a clean pure cotton rag, or wrap some alfoil over it and tie it on with a bit of string, and open the gate valve wide.
Ther is no special ratio of vinegar to water. More vinegar does the job faster. Can't remember, but is your column copper or stainless? If its copper you might be better off just soaking it in vinegar for a day or so.
HookLine wrote:Yeah, just plug the top with a clean pure cotton rag, or wrap some alfoil over it and tie it on with a bit of string, and open the gate valve wide.
Ther is no special ratio of vinegar to water. More vinegar does the job faster. Can't remember, but is your column copper or stainless? If its copper you might be better off just soaking it in vinegar for a day or so.
I soaked my Liebig in vinegar for a day.
Thanks hookline - it is copper. I will give it a run to check seals and get to know the beast. I might also do a soak, but I want to get the feel for the rig before I run a wash through it.
I tried cleaning my VM still yesterday. I got maybe a pint of condensate out of the liebig product condenser.
I was pushing about 5000 watts into the boiler. Nothing was coming out the top of the column. The output water in my reflux condenser was HOT. If I cranked the heat up much more than 5kW, I'd get vapor out the top. This went on for abot 1.5 hrs.
I was thinking something has to be wrong! I can hear my vinegar/water solution boiling away but nothing is coming out the top and practically nothing out the liebig.
Then I remembered reading something about a VM column's product output will stop once ABV drops below a certain point. Vinegar and water has no alcohol in it. No wonder there is no output.
Alcohol vapor is heavier that air and it prefers to flow out the VM port when it reaches that height, just like water would if it were being pumped up your column, following gravity. Only the excess that will not fit through the VM port will continue up and be condensed by your RC.
Water vapor is lighter than air and prefers to keep going up your column, past the VM port and straight to your RC to be condensed. Only a minimal amounts will find its way to your PC.
Last edited by OtisT on Mon Apr 21, 2025 5:33 am, edited 1 time in total.
Cmonster wrote: ↑Thu May 01, 2008 7:31 pm
Is it appropriate to put a rag plug in the top of the column providing the gate valve is open and thereby forcing the mix down the liebig?
Partially block the vent and make sure the take-off valve is open with the RC cooling water off. Treat it like a potstill for the vinegar run. A gallon or two of 3% vinegar and more than enough water to guaranty the element stays covered is good enough.
During the sac run, when there's alcohol in the pot the VM rig is going to behave totally different than water and vinegar.
shadylane wrote: ↑Sun Apr 20, 2025 12:09 pm
when there's alcohol in the pot the VM rig is going to behave totally different than water and vinegar.
Re: VM cleaningPost detailsQuote OtisT
by OtisT » Mon Apr 21, 2025 3:26 am
On that same note, for those who might oneday need to know, plated columns also behave very differently on a vinegar cleaning run.
Often plates won't load or are extremely hard to get to load.
When I do a vinegar/water cleaning run, I've always used a 1:1 ratio of water to vinegar.
1. I open the gate valve, plug the top hole with a cork (or 100% cotton cloth), blast the steam through the entire still and out of the product condenser. Blow the steam outside through an open door or window.
2. After I'm satisfied it's cleaned out enough, I remove the cork, run water through the reflux condenser and let it run for a good while with reflux.
3. Shut down and thoroughly rinse everything very well. It doesn't hurt to put some water in the boiler, repeat step #1 by blasting steam through the still again. It just helps to ensure all the vinegar is completely gone.
Next do a relatively small sacrificial alcohol run, shut down and thoroughly rinse.
