Star San Tips – Materials Compatibility + Do Not Soak

star san materials compatibility

Star San is my homebrew sanitizer of choice.  When mixed properly, it’s food safe and no rinse.  Required contact time is five minutes.  It has worked very well for me for quite some time and I’m convinced that it’s one of the most economical solutions available if you’re using the “Spray Bottle Method” outlined here.

Star San Materials Compatibility

When Valuebrew released FDA Rated EPDM Keg O-Rings I did some digging on EPDM and learned that it’s pretty cool stuff. EPDM is the choice of many professional brewers and has some real advantages over silicone. One of the big ones is a much lower permeability. That means they seal better and since they’re less porous they are more resistant to absorbing off-smells and off-flavors.

Anyway, that’s the back story behind this section. While researching EPDM I found some nice materials compatibility charts showing what materials were compatible with what chemicals. Nice!

This made me wonder, what about Star San and PBW??

I reached out to Five Star Chemicals for some information on the subject. Unfortunately, a comprehensive run-down of compatibility was not available at the time I reached out to them.

I received this response from Ryan Alcala at Five Star Chemicals… “When it comes to our products they are compatible with stainless steel, glass, and rubber. They are not however compatible with softer metals like copper and aluminum.”

There are lots of materials we use that aren’t specifically listed in that list. I’m guessing both Star San and PBW have good compatibility with many of the materials we use. But, without a resource outlining materials compatibility, there is no definitive answer.

I can tell you from personal experience that Star San dissolved a plastic gallon jug that I had used for storage. It took a long time, but it started to dissolve the plastic. What kind of plastic was the jug?… I don’t know. But Star San was not compatible with that plastic for that amount of time. That Star San solution had dissolved plastic in it.  This is why I went to glass jugs.

That story is an illustration to make the point that just because we can’t see something happening doesn’t mean it’s not happening. Is Star San or PBW breaking down keg components, tubing and more?  I don’t know.

Personally, I’m going to try to limit contact time for both Star San and PBW as much as possible. Minimizing contact time will minimize any negative affects these chemicals have on homebrew gear.

Do Not… Soak

My initial thought is compatible = compatible. But… there’s also a time component. Just because Star San is compatible with a material doesn’t mean it’s compatible for any conceivable length of time.

From my contact at Five Star Chemicals… “Star San is an acid based sanitizer so if you are just leaving a piece of equipment soaking in it for hours it will eventually damage it”

Contact time for Star San is five minutes. That’s about how long you should leave a part sitting in Star San. Excessive time can cause damage.

Two materials that are an exception to this are stainless steel and glass.

But… Star San Comes In a Plastic Container

Yes, Star San does come in a plastic container. If everything you use in your home brewery is made from the same formulation at the same quality and then… you’re probably good to go. But… it’s not. There are all sorts of formulations (and quality) out there. Five Star’s official recommendation is to stick to Star San’s contact time.

This write-up is part of my Star San Resource Post – Jump To This Section

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Make sure the components you use are compatible and rated for your intended application.  Contact manufacturer with questions about suitability or a specific application.  Always read and follow manufacturer directions.  toppost:starsanspraybottlemethod lnksto:starsanspraybottlemethod tag:lnksfxd rp:lnkssdonotsoak

2 thoughts on “Star San Tips – Materials Compatibility + Do Not Soak

  1. butcht

    Star San comes packaged in an Plastic Jug! HDPE is resistant to many chemicals, but the cheaper milk/water jug type are sensitive to UV rays, like from sunlight or fluorescent lighting.

  2. Jon R Davison

    Thanks for the advise. I will limit contact time with plastics from now on. I do have a plastic ZEP spray bottle that I have kept StarSan in for years without problem, but I also use aquarium airline tubing that has gotten cloudy after soaking for extended periods.
    Jon D


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