I don’t trust the internets so I’ll ask the branez trust. Is it safe to use a dilute bleach solution for soaking stainless steel water bottles? If not, what’s the reaction that occurs? I used to do this for my plastic bottles with good results, but I’m wary of doing it with SS. And if it isn’t, what’s a good replacement?

2 Fe (s) + 3 NaClO (l) → Fe 2O 3 (s) + 3 NaCl (aq)

OCDC said:

I don’t trust the internets so I’ll ask the branez trust. Is it safe to use a dilute bleach solution for soaking stainless steel water bottles? If not, what’s the reaction that occurs? I used to do this for my plastic bottles with good results, but I’m wary of doing it with SS. And if it isn’t, what’s a good replacement?

Would depend on the type of stainless steel as to severity, I’ve never used bleach on mine. All halides promote corrosion as they interfere with the chromium oxide passive layer protecting the iron.

Use vinegar.

OK. Probably completely safe.

There are a lot of aspects to this so I’ll cover some of them.

1. Metals corrode in both strong alkaline and strong acidic conditions. But corrode much faster in strong acidic conditions.

2. There are different grades of stainless steel. The one used in sinks is one of the less robust alloys, ie. there are stainless steel allows that are much less easily corroded than the alloy used in the home. They are used in chemical plants and food processing factories.

3. There are two quite different ways in which metals resit corrosion. And aluminium illustrates the difference. One method is bulk chemical resistance to corrosion. The other way is when the metal develops a surface layer that resist corrosion. Aluminium develops a surface oxide coating that resists bulk corrosion, but that doesn’t protect against pitting corrosion, corrosion in pits that pass behind the surface oxide layer.

4. Mild steel does not develop an oxide layer that resists corrosion. I made the mistake of leaving undiluted bleach for ten minutes in a porcelain sink that had a chrome plated outlet fitting. The bleach corroded the part of the steel that was unprotected by the coating, out of sight. And left an ugly rust stain.

5. I think you’ll find that normal stainless steel sink will resist the pH of the bleach. It would be designed to. My fitting that corroded was chrome plated, not bulk stainless.

So let’s see what the web says about this.

“Stainless steel 316 can be used for the entire pH range from 0 to 14 (provided the chloride content <500 ppm).”

“Bases. Stainless steel offers strong resistance to weak bases in both high concentrations and high-temperature environments. However, stronger bases will cause cracking or etching corrosion. Particular care must be taken with chloride solutions such as sodium hypochlorite.”

> stainless steel allows

stainless steel alloys

Thank you branez trust.

OCDC said:

Thank you branez trust.

No worries.