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Cleaning Stainless Steel Fermenter

Hello all,

I wonder if anyone can help me ?

I am having a terrible time trying to clean my fermenter it’s an SS Conical 7 gallon.

There is a lot of residue (old hops etc I guess) that I just cannot get off.

I have tried soaking it over night in a solution of chemclean at a ratio of 60g to 25 litres of water. This had almost no impact at all :frowning:

I’ve attached a couple of photographs

Can anyone suggest a good deep cleaning method ?

Many thanks


By the looks of it… it hasn’t been cleaned a couple of times ago…
I’d take all the components apart… get some barkeepers friends, powder form, and a green scour pad or two… perhaps a half gallon of elbow grease… get it damp and start scrubbing… do half at a time rinse and repeat until it’s shiny…
Clean the other components the same….
After that, after every use, you need to clean it so it’s shiny…
Have you had any soured batches of beer from it?

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Yes I reckon the past 2 batches have had a bit of an off flavour on the finish

I have tried to clean it several times before and just believed that it was becoming a bit tarnished.

Thank you for the advice - looks like bar keepers friend it is !!

Brewing is mostly a hobby in cleaning. I’m not the cleanest person but my brewing equipment is spotless. You will get the hang of it. PBW is my go to with all stubborn stains

That’s beerstone and will require an acid. Bar keepers friend will work but will require elbow grease and your at risk for scratching your SS. I would suggest you purchase this beerstone remover from Five Star or Acid #5 also from Five Star.
How have you been sanitizing? After getting your SS cleaned up I would suggest sanitizing with Saniclean from Five Star. It is an acid rinse vs. and acid wash and will assist in eliminating beerstone.

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For the record- I am NOT affiliated with Five Star Chemicals by any means.

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Agree its beerstone and beerstone remover way to go. For more info on beerstone

Looking at the amount there, either it has not been cleaned in a while and/or you have really high mineral content in water like a lot of UK water? Do you have trouble when mashing non dark beers meeting the mash pH 5.4-5.6? You will get off flavors and other problems if you don’t hit the mash pH.

Thank you - greatly appreciated :blush:

Hello @loopie_beer I have been cleaning with Grainfather cleaner and sanitising with Starsan. A few brews ago I didn’t get to clean the fermentation tank for a few weeks after emptying and this was the result.

Though I have to say I did notice some deposits before this but believed as long as I cleaned and sanitised everything would be fine :frowning:

I have one other question …… sorry !!!

If I really go to town on cleaning like with acid or barkeepers friend - will I have to re-passivate the fermenter if so - how do I do that ?

Many many thanks


Hello @mikem i suspect you are right about the water here in the UK. I haven’t been brewing for too long so I have never deployed any kind of water chemistry - feels like something I should be doing as this can also prevent beer stone ???



Water chemistry is a great big rabbit hole… The one I feel is most important is Alkalinity… that is what leaves alot of the white residual from our water here… pH is a target for the mash conversion….
Post boil wort IS so susceptible to contamination… so sanitizing is your defense… the fermenter should be very clean… I’d even go to spotless… and pitching healthy yeast… this regiment ups the odds of having good, drinkable beer…

Water chemistry is indeed complex. I believe UK water can sometimes be very alkaline and also can have very high calcium levels. I think I remember seeing calcium levels as high as 300 ppm in some UK waters. If you are doing all grain brewing it is important to hit the mash pH. Even in extract brewing if you are above 200 ppm Ca it can make beer taste minerally.

Its a rabbit hole as others have said. If you want to understand it better read Palmer how to brew. Here is link to an older free version

If your water has too high levels don’t fret, you can always blend it with distilled water or reverse osmosis water.

Pardon my jumping in but since you are scrubbing the heck out of it, you probably should passivate it. Bar Keepers friend contains oxalic acid which will passivate it if you use it to clean.

Here is additional info on how to passivate and when to passivate.

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Guys thank you all again - this is excellent advice and @mikem thank you for the articles to read.

I’ll let you know how I get on next weekend !!!


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Thank you Mikem…. I haven’t a clue how to add those articles…

@rodmat sorry about the late response. Passivation is easy using the products I linked. Simply let them air dry. So not only do they clean, they passivate if you ACID WASH FIRST. For acid #5 simply recirculate 5oz/gal of water for 30 mins and then let air dry. You’ll need to RINSE and SANITIZE AFTER it air dries. THEN, once clean sanitize with SaniClean EVERY time. It’s an acid RINSE which should fend off beerstone. Depending on what beer you make and water composition you may need to acid WASH every so often. You’ll need to determine that based on your results. It might be once every 3 beers; might be once every 10 beers. YMMV. Now, that’s one of the nastier tanks I’ve experienced so you might need hit it multiple times to get it spotless.

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Hello guys I thought I’d post the results of your guidance and support.

In the end I used bar keepers friend straight from the can, I had 3 goes at it in the end and then I soaked and rinsed the whole thing in five star BS Remover (I think that will have passivated it ?)

Thank you :pray: all



Now that’s a nice fermenting kettle! I second what has been said about brewing. “25% brewing, 75% cleaning”…
Keep after it and you won’t have an extended cleaning week!

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Looks good! And yep, it’s passivated now.

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