Have used Star-San for years in my home brewing, I recently saw some information on the web that it should not be used on aluminum substances, i.e. pots, kegs, etc. Reviewing the pdf about Star-San I don’t see any mention of avoiding contact with aluminum. Anything to this information? If so, what if you left some diluted Star-San in a keg for a period of time by accident?

2 Answers 2


Kegs are stainless steel, not aluminium.

Starsan is actually a good acid to pacify (restore oxide layer) Stainless Steel. Spray and let air dry.

Aluminum is treated completely different. Though it does have a fair to good rating for the acids in starsan. https://www.industrialspec.com/images/files/aluminum-aluminium-chemical-compatiblity-chart-from-ism.pdf

Aluminium would not be a good storage container for mixed starsan IMO.

As far as SS kegs, I've had starsan in them for weeks with no I'll effects. I've also aged sours in them for over a year with pH as low as 3.2 with no issues.

  • Most kegs are stainless steel, but aluminium kegs definitely still exist (and probably more so in circles of people who tend to buy second-hand rather than new). Commented Sep 13, 2018 at 16:12
  • StarSan really isn't going to passivate a stainless steel surface, either. Phosphoric acid in general isn't effective for passivation, and at a concentration of less than 0.08% in properly diluted StarSan it won't be doing a thing. Any passivating effect will come from direct contact with atmospheric oxygen on drying. Commented Sep 13, 2018 at 16:17

I've never used StarSan for economics reasons. But I remember reading something on John Palmer's book "How to brew".

Do not clean aluminum shiny bright or use bleach to clean an aluminum brewpot because this removes the protective oxides and can result in a metallic taste. This taste-detectable level of aluminum is not hazardous. There is more aluminum in a common antacid tablet than would be present in a batch of beer made in an aluminum pot.

You can find this on Appendix B.

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