Does anyone have a magical solution that brings back copper to that brand new bare copper look? I have to use copper packing in my still and it comes out looking pretty worn out. I have tried various acids, but nothing very impressive yet. Since it is packing, it can not be scrubbed, so something that works as a soak would be best. Thanks in advance!
Reply:Does anyone have a magical solution that brings back copper to that brand new bare copper look? I have to use copper packing in my still and it comes out looking pretty worn out. I have tried various acids, but nothing very impressive yet. Since it is packing, it can not be scrubbed, so something that works as a soak would be best. Thanks in advance!
A simple soak in undiluted plain white vinegar will do the trick. Let the packing soak for a couple hours and it'll be good as new. Some people swear by adding salt to the vinegar, but I haven't tried that.
Also, try hot spent rum wash. That works pretty well, too.
I bought my copper mesh from Amphora Society
I asked Mike how to clean it
email from Mike Nixon
Many thanks for ordering four (4) pounds of the mesh. Your card has been charged US$70.00 ($60.00 for the mesh with $10.00 shipping)). This will appear on your statement as NZ$94.72 at the current exchange rate, as payment to Silver Key Ltd, Auckland, New Zealand, the parent company of the Amphora Society.
Your mesh will be shipped to you from our US distribution center immediately.
As for looking after the mesh, you need to clean it occasionally as it turns black. This is a deposit of sulphides, which every carbohydrate ferment has, and you want to remove it from the vapor and liquid as it can lead to some rather nasty smells and tastes.
Cleaning is both simple and easy. Best done by carefully sliding the slugs of mesh from the column, but not unrolling them. To a liter of hot water, add two heaped teaspoons of citric acid (as used in baking the white powder) and the same of common table salt. Now soak the mesh in this solution. Periodically, remove the mesh and reheat the solution in the microwave (not to boiling!) as chemical reactions proceed quicker at raised temperatures, and citric acid is a very weak acid. The salt is there to promote molecular activity withing the solution, so helping the reaction along. You'll find that the mesh looks almost like new after 20-30 minutes. Rinse it well, then leave it to soak in a bucket of clean water overnight to get rid of the last traces of chemicals (add a teaspoon of baking soda if you like). If you don't soak it, then you'll probably find it turns a bit gray after time, this being due to oxidation in the presence of traces of citric acid. After soaking, you should find it looks just about the same as new mesh. The reaction does remove a small amount of the copper, but only a few parts per million. In 6 years of repeatedly cleaning the same slugs of mesh, I have not noticed any perceptible diminution in the threads, nor have we had any reports of others suffering damage.
All the best,
Paul- you beat me to the same recommendations. Any acidic, spent wash, hot from the kettle, with a short soak, cleans it up 90% of the way. Every now and then a vinegar soak. Then a short soak in water with a bit of bicarbonate of soda.A simple soak in undiluted plain white vinegar will do the trick. Let the packing soak for a couple hours and it'll be good as new. Some people swear by adding salt to the vinegar, but I haven't tried that.
Also, try hot spent rum wash. That works pretty well, too.
We use Sodium Hydroxide to clean and soften up the build up then a rinse using a citrus acid to finish it off. Coop
There is a lot going on chemically on the copper. The first concern is a "stone" similar to a beer stone. This is an organic material that the copper has pulled from the distillate. Use the Sodium Hydroxide NaOH (also known as lye or caustic soda). This is a strong caustic with a very high pH. It has a high affinity for hydrogen ions and will strip them from the stone. It is denaturing (if you will) the organic molecule (think puncturing an egg yolk) and this softens the built up layers. If you get it on your hands it will have a "slimy" feel. This is because the caustic is denaturing your skin and the slimy feel is dissolved skin.
Use it hot (120 - 160) but not boiling and be VERY careful. 5% Sodium Hydroxide solution is a very effective cleaning tool but also very, very dangerous if not used properly. NaOH does not rinse of easily with just water. It takes a LOT of water to rinse it off. I would recommend a weak citric acid solution or vinegar close by to neutralize the caustic. And of course use goggles and gloves. Read the MSDS carefully.
Let is soak for 30 minutes. And depending how much build up you have it may take 2 -3 NaOH cleanings.
The next concern are the inorganics or the "tarnish". An acid such as citric acid will work well. Unfortunately for tarnish to be totally removed (to look like brand new) using citric acid it takes some elbow grease. And since you probably cannot access the area you have a concern over you will just have to live with what the citric acid will remove.
After the caustic cleaning follow with a 5% citric acid solution (low pH). This will neutralize the caustic soda and help remove some of that tarnish. One way to know if you have neutralized all the caustic soda is to check the pH of the citric after it has been rinsed through the copper. If the pH is over 7 then you will have to add more citric acid to get the pH down. A lower than 7 pH left in the still will not harm anything. And citric does rinse off easily with water.
Citric acid also will "sweeten" the surface and make it inhospitable for microorganisms. While citric is safer to use than NaOH you should still use caution and read the MSDS sheets.
Finally do NOT mix citric acid with bleach. It will produce chlorine gas which is deadly.
Thanks for all the type! I have started experimenting with the citric acid and it seems to be doing the trick.
Is there a clean-in-place recommendation for cleaning packing? How about flushing the column with hot water, then pumping a 5% NaOH solution up the condenser and down the column (and through the packing) followed by pumping a 5% citric acid solution? I was thinking that I could do this each day after running the still.