Yes, I know about the rusting of iron. I added copper cents to provide copper in the distilling process. But I learned that copper is very destructive to iron in a corrosive environment. So maybe I did very wrong in putting pieces of copper in a iron distilling kettle.still_stirrin wrote:Carbon steel will rust and galvanized steel is zinc coated. In the presence of hot alcohol, zinc will become toxic...so it is NOT approved for use in a still.Kareltje wrote:...recently I added some iron or galvanised nuts and pieces. For I started to doubt the effect of copper pieces in a iron still...Now I have a copper still, so I do not need boiling parts of copper any more...
I did not find anything about the toxicity of zinc in presence of hot alcohol. If you have any sources, please tell me.
Thanks, I will study it.still_stirrin wrote:Well, the composition of US pennies (since 1982) contains 97% zinc with only 3% copper plating. Here's a link which discusses the history: https://en.m.wikipedia.org/wiki/Penny_(United_States_coin" onclick="window.open(this.href);return false;" rel="nofollow)Kareltje wrote:...You are familiar with the making of your pennies. Can you tell me more about it?...And why is it not advisable to have non-copper boiling stones?
I have to point out a misunderstanding: I used cents of my own country, until 2001 made of copper. Since 2001 our eurocents are made of iron, clad or coated with copper. I still use old cents or odd pieces of copper as boiling stones. But our eurocents can be used as well.still_stirrin wrote:But again, the reason NOT to use pennies is the zinc which reacts with the hot alcohols. The only approved metals for use in an alcohol still are copper (the real thing, not simply copper plated) and stainless steel.
As there are many alloys of SS, the preferred series are the 300-series stainless steel, in part because they can be welded. The industry standard for most breweries, distillaries, and dairies is the 304 stainless.
And it is quite off topic, but about the approved (by whose authority???) metals we can start a large dicussion.