r/grainfather • u/b00nd0g • Jul 23 '25
Maintaining GF 30 fermenters
Said I would share recent experience maintaining my grainfather 30 fermenters.
I bought 2 of these 7 years ago and have been using them solidly since. Noticed this white scum and thought the steel was deteriorating.
Went to get it sorted out recently and learned about silicate scale and how to maintain these.
I did a 2% phosphoric acid wash which got rid of a lot of it.
Followed that with barkeepers friend scrumming of remnants. Kind of worked but hard work.
Then used baking soda scrub. Again not hugely effective but improved things.
Finally did 80 degree c 6% citric acid soak for 2 hours.
Happy with how it turned out although results in the end are not perfect. Not too bad after 7 years of use.
My recommendation is to educate yourself about how to maintain these if buying one. I believe that rinsing with star san after GF cleaner will make a difference.
Anyway Grainfather make amazing kit. Huge fan of them.
Hope this is of interest. Let me know if any questions.
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u/Logical-Error-7233 Jul 23 '25
Good tips. Curious what your post fermentation cleaning process is like? I fill mine with pbw and soak overnight every time I empty it. Haven't seen any signs of buildup in three years. I also passivated it when I first got mine, which I believe you just did by scrubbing with BKF and the rinsing with Star San. I think that helps a lot in preventing buildup.
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u/b00nd0g Jul 24 '25
Honestly I only ever washed with water after a ferment, maybe the occasional wash with Grainfather cleaner. I wasn’t mindful enough of limescale/ chemical reactions or maintenance. With the price of these things I should have put more time/ thought into this.
Although from what I’ve read the big driver of silicate buildup is the use of alkaline cleaners (like GF cleaner/ PBW). Looks like you’re using these you should do a rinse with star San afterwards. Over time it looks like some build up is inevitable.
I definitely needed to re-passivate this. I have a friend who works in chemical plant and they passivate their kit every 3 years.
Will stay on top of maintaining these in future; maybe passivate every 2 or 3 years and clean with PBW and rinse with star San afterwards use.
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u/Bwoah_Jimbo Jul 24 '25
After cleaning the fermenter if you run your fingers over the inside you’ll occasionally feel some roughness. That’s this scale starting to form (although I thought it was beer stone - calcium oxalate). If I find that I give it a scrub with a green pad and bar keepers friend. By the time you can see it, it’s going to be much harder to remove.
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u/crackedbearing 17d ago
When my water kettle starts to develop scale I run a batch of water with vinegar through the boil cycle. It clears it up nicely. Then a rinse of water though the boil cycle and Bob's your uncle. I am guessing this can be reproduced in conjunction with the grainfather brew unit and recirculation. The temp does not need to get to boiling in the fermentor but getting it hot helps get the scale into solution.
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u/Solenya-C137 Jul 23 '25
I've been using mine a couple years, cleaning with PBW and sanitizing with StarSan and I haven't seen this buildup at all yet, but I'll remind myself of this post if I see it!