Rust Spots On Stainless Kettles

[kgranger]

A little background: I've set up shop in a detached garage, no heating, fairly uninsulated, so it gets pretty cold. Spike Brewing 15 gallon system, E-HERMS, lots of stainless components. I have water running from the garden hose (drinking water safe hose) into the brew space, running into a 10 micron water filter. The spray down hose is not on the filter - I figured it would be fine for rinsing PBW off.

I noticed the water from the hose is very hard - lots of water spots. Tastes fine, but definitely lots of minerals. After my first "dry" run with water, I rinsed out all the kettles, ran a CIP through the whole system with Star San, and left to air dry. I noticed the next day small rust spots here and there, around the bottom of the kettles where the star san didn't fully dry.

It gets cold in there, so even with a dehumidifier, it isn't bone dry. I thought the acid in the star san would act as a bit of a barrier, similar to passivation, and having it be completely dry wouldn't be an issue.... but it definitely is. I will start disassembling everything and flipping the kettles upside down to help in drying, but I have a feeling this won't be enough.

I have a theory that the main issue is not that it isn't completely 100% drying all the way - I've never had issues air drying with a little star san left at my old place. I believe the hardness of the water is accelerating the rust formation.

I looked into water softeners, but they are close to $400 for one that would suit my needs. Before I pull the trigger on getting one, does this sound like it would actually help? Is the hard water causing overnight rust? I can't really change the fact that the garage is cold at night, and won't dry all the way. But again, never an issue in my last brewing space indoors where the water was much softer.

I appreciate anyone willing to read this huge post all the way and possibly offer any suggestions!

 

[RPh_Guy]

You don't need to change your water. Simply using proper cleaning techniques will avoid this problem.

Star San does not passivate or provide any kind of "protection" to stainless steel.

Do not use Star San on your hot side equipment. There's absolutely no reason to chemically sanitize it.

Do not allow acids or other chemicals to remain on your equipment for extended periods. Allowing concentrated acids to air dry on stainless is known to cause corrosion.

The only time you need to use a sanitizer is immediately before use, and only on cold side equipment.

BKF will remove the rust if needed.
You can consider passivation with nitric or citric acid.

 

[SEndorf]

You don't need to change your water. Simply using proper cleaning techniques will avoid this problem.

Star San does not passivate or provide any kind of "protection" to stainless steel.

Do not use Star San on your hot side equipment. There's absolutely no reason to chemically sanitize it.

Do not allow acids or other chemicals to remain on your requirement for extended periods. Allowing concentrated acids to air dry on stainless is known to cause corrosion.

The only time you need to use a sanitizer is immediately before use, and only on cold side equipment.

BKF will remove the rust if needed.
You can consider passivation with nitric or citric acid.

^
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This

Concise
Well stated
100% accurate

 

[kgranger]

that all makes sense, but I still wonder why this is an issue for me now, when my precious stainless equipment has air dried with Star san for years of brewing. Maybe the temperature is really the issue? It has been down to 40 degrees recently. Not much I can do about that part, as it is I insulated.

I’ll probably just have to microfiber cloth large surfaces dry, and disassemble components to dry.

 

[odie]

metals in the water...iron and such in the water spots that are rusting...wipe down excess water may solve your problem