Copper plays a big part in distilling. It helps to clean up washes with access sulfur, under certain conditions, and it looks good. Those two reasons are probably why so many stills are made out of copper.
But why isn’t the iStill made out of copper?
There is a reason for that. Even though copper has its qualities, using copper imposes a risk. The risk of copper poisoning.
Now on a rig that is ran on a daily basis, this risk is minimal. The extended copper/alcohol contact prevents copper corrosion.
But when a copper still isn’t put to service at least twice a week, copper – under the influence of oxygen – can compound. If the copper pot, column, or product cooler aren’t treated with detergents, that is.
This process of compounding or rusting enlarges the surface area of the copper very much and weakens the integrity of the copper. Your still won’t break down, but copper parts, or better: particles, will come of the inside of your column or product cooler.
Those particles, by means of vapour or liquid transport, can come over in your drink.
Ingesting some copper is not a problem. The body can get rid of it and there is a safe trash hold of around 5 milligrams per person per day.
But what is 5 milligrams? Five milligrams is just 0.005 grams and that is not much.
Suppose that you ingest, by drinking tab water and eating food, around 2 milligrams of copper on a daily basis. That means there is a safety margin of around 3 milligrams a day.
But what if you drink a whiskey or vodka from a copper still that hasn’t been cleaned properly? Could it cause additional copper ingestion to the level copper – a heavy metal after all – gets poisonous?
Yes it easily can. Our research shows that unclean copper stills easily contaminate a drink to above healthy copper levels. With a safety level of 3 milligrams left, it just takes 10 copper particles, the size of cigarette smoke particles, to breech the safety trash hold. And if you break that thrash hold for a longer period of time, copper poisoning will start to take effect.
That’s why our stills are made out of stainless steel. And that’s why we place our copper catalyst as low in the column as possible. The low placement adequately prevents liquid induced as well as vapour induced copper contamination of your drink. Possibly contaminated liquids fall back into the boiler. Potentially copper contaminated vapours are redistilled many times in the non-copper packing above the copper catalyst. That way these particles are also refluxed out of the vapours and do not travel over in your final spirit.
There are two more steps you can take to minimize copper contamination even further:
- Put your copper Rashig Rings or copper SPP under 40% alcohol after the distillation run is done. The alcohol will prevent oxygen to get in contact with the copper.
- Clean your copper Rashig Rings or copper SPP with a 50/50 mixture of water and Cola for up to 12 hours priot to a run. No need to do that every time. But once a month will make a difference and keep your copper in shape!