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Permalink Reply by Phil Proteau on July 14, 2009 at 10:29am

I do not know about the electrolytic reactions in the boiler, but I do know that the minerals will build up because the steam boiler is constantly letting out steam. This leaves the mineral content behind. So the rising level of minerals in the boiler is not caused by reactions, though reactions may make them stick in certain places. You may be able to make the minerals deposit on specific surfaces if you like, but they will accumulate regardless. Even if they just sink to the bottom to form sludge. The accumulation of scale is not the same thing as corrosion. I cant remember ever seeing a case of a Galvanic reaction in an espresso machine (although I am sure it has happened). It is just a different topic from scale build up altogether.

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Permalink Reply by Tim Brisnehan on July 14, 2009 at 11:02am

OK, that makes sense. I guess I've just been blowing through all this material on water and every time I saw terms like "corrosion", "scale buildup", "rust", etc. I went "bad flaky stuff". They are not different species of the same reaction, I stand gratefully corrected.

On any of the lists I can find, our metals, copper, brass, and stainless, are fairly distant in terms of standard potential, and I think the water we use (say 100mg/L hardness, 50mg/L alkalinity, neutral PH) can act as an electrolyte. What would be the signs of a Galvanic reaction, would you expect to see noticeable loss of mass on anodes?

My concern is that a less noble piece (a copper fitting, say) would corrode in the presence of brass or stainless, but when leaking happens, we would just see a big smear of dripped mineral hardness, tighten or replace the fitting and assume the problem was fixed, though it seems bound to recur. Plausible?

It's likely that I understand these things poorly enough that this is not, in fact, an issue. Thanks for helping along a new guy!

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Permalink Reply by Denise Smith on July 14, 2009 at 3:15pm

We use a small water softener (as required by manufacture for warranty) and then filter that through a good quality water filter. So far... it's worked and the coffee tastes great! On the brewers it only goes through a filter and the coffee build up is lightly higher there requiring more cleaning.

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Permalink Reply by Bill Warnock on July 17, 2009 at 9:46pm

on boats it is to prevent electrolytic decomposition of the metals, bigger boats even have a system that is connected to the battery I say bigger because they are more frequently left in the water longer than small boats that can be trailered. I was wondering the same thing we talk an awefull lot about machines, tamp pressure, temp, time, all of this but it takes minerals in the water to "pick up the coffee in the water" we know this by help of a tds meter. But what is the magical hardness, alkalinity, chlorine, chlorine free- numbers?????!!!!!

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