taste alterations with pure water test runs

[cyrusvalkonen]

So I have asked before, what kind of taste alterations are present, if you test run your still with pure water only.

Unfortunately people got very confused because I mentioned the word "plastic".

The questions asked pertained to how different equipment could produce different alterations. For example mixing copper with stainless steel causes electron migration, which releases nickel and chromium ions in small quantities. This could produce a bitter or metallic taste (which is already noticable if you boil water in a stainless steel pot, due to extremely high amounts of chromium and nickel used in stainless steel cooking ware).

Another source would be the solder used and flux. Some people's stills are crafted from scratch out of small pieces of copper sheets and do use copious amounts of both. While it is true that someone very skilled could produce almost seamless solderwork, hence vanishingly little surface area to influence the end result, I don't think that's usually the case. It is also true that ordinary flux and solder are designed for water pipies (and not for high-heat alcohol stills), where a calcified protective barrier forms over time to seperate the metal from the drinking water. This is for example why copper pipes for drinking water were still commonly soldered with leadeded solder until the 80s and 90s, but the negative health effects of the lead solder overall remained small to non-existent. In an alcohol still, this would not have been so.

I would be very interested about your experiences in pure water test runs with any particular equipment.