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One hears a lot of different comments regarding the use of galvanized or bronze pipe fittings.

I have a 50L urn as my boil tank and I want to replace the tap, but the tap is an odd size - 17mm - and I can not find a stainless steel ball valve of that size.

But with a galvanized washer and ring attachment I can fit a 15mm galvanized ball valve.

What are your guys comments re: galvanized pipe fittings in the brewing process?

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  • Thanks for all the feed back, I found the correct SS fitting but had to modify the urn tap hole André – Andre Erasmus Jan 26 '18 at 19:55
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Galvanized steel I would not use. The galvanized plating only has a pH tollerance above 5.5 and will corrode from most wort. The part won't fail any time soon from wort, but those metallic ions stripping off will then be in your beer.

Bronze also has metals you wouldn't want in beer (tin)

Brass is a much better metal to use if stainless isn't an option.

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Don't use galvanised it will corrode rapidly below pH 5.5, also it is unlikely to be food safe.

NEVER use bronze, it is not food safe, will corrode, contains tin and may contain lead.

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I suspect that from brew to brew the effect of contact with a zinc plated washer will be negligible. The zinc would (very, very) slowly dissolve under the effect of acid conditions and, generally speaking, zinc ions in solution are "not optimal" for yeast metabolism. But IMHO the amounts of zinc compared to the amount of yeast would again render the problem negligible.I was wondering what electrolytic effect a zinc/iron dipole might have, but again I don't suppose that would be significant of the course of 10 days or so. If the zinc washer was the only viable solution in the circumstances then I would certainly give it a go rather than not brew at all.

Would it be possible to coat the zinc washer in (say) epoxy resin? Would it be possible to make up a suitable washer by cutting a drilling some stainless sheet? It is certainly possible to obtain stainless steel washers of various sizes online.

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  • Interesting answer. The zinc gutter of my parents' house is mounted on iron decorations. This is iron is corroded because of the zinc. So I suppose that in the case of steel and zinc, the steel will become corroded. With aluminium and iron, it is the reverse. On my bike it was always the aluminium mudguards which corroded because the light was mounted with a steel screw. – chthon Jan 26 '18 at 14:45
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mmm interesting question. From a corrosion perspective I wanna say that is kinda risky. Galvanized steel being in contact with stainless steel is usually fine, but in this case you are also putting them under heat and acidic liquid conditions, so I'd say to best avoid it.

Maybe consider a 17mm-to-Xmm stainless fitting that can be hooked to another stainless valve of size 'X'?

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The actual exposed area is so small, I don't think there is any risk. Things might corrode over time, but if it gets bad enough, just replace it. You can't really find a SS fitting?

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