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Sanitizing a Stainless Steel Fermenter

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cpsmusic

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Hi Folks,

Had some problems with my last two batches tasting "vinegar-y". The problem has been diagnosed as an acetobacter infection, most likely from my plastic fermenter. As a result I decided to ditch the old plastic fermenter and upgrade to a stainless steel one: https://www.ssbrewtech.com/products/brew-bucket-mini.

In the past I've used Oxyper for cleaning and a no-rinse percarbonate (88%) sanitizer: http://www.brewcraftsa.com.au/showP...ents/40016/BEER+ESSENTIALS+NO+RINSE+SANITIZER

Just want to check that these will be ok to use with the new stainless steel fermenter.

Cheers,

Chris
 

captnhaddock

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Yes, that will be just fine. While I do use a generic no-rise, I personally rinse after using the cleanser / sanitizer, and then re-sanitize prior to my next batch using starsan.
 

MHB

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Where I work the Fermenters (well everything really) gets cleaned
Every Brew
Manually - hose and a scrubber to remove crud (Krausen ring, yeast sediment, crud on heating surfaces...).
Caustic Soda - 1.5-2% hot through the spray ball - seriously nasty
Rinsed - Clean water before use
Proxitane - Just before filling

Hot acid wash about once a month, used hot and strong enough to passivate the stainless as well remove any buildup of beer stone.
Before I used any new Stainless equipment I would clean with caustic (at home maybe something less aggressive) first to remove any oils then passivate it.
Don't know where you are located but if you have a local craft brewery have a chat with the guys there they can probably help you with some of the industrial strength passivating chemicals (usually a blend of Nitric and Phosphoric acids). Make sure you use to instruction.
Getting the surfaces clean and passivated before you use Stainless makes a big difference to how clean it stays, keeping beer stone under control will matter later. I've see some home conicals that looked like they had coral reefs growing in them, impossible to keep bacteria under control.
Mark
 

captnhaddock

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I will point out that ssbrewtech only recommends that you passiveate when you first get the kit, and then once yearly from there on out.

I also wanted to voice concern about using caustics as, well, how caustic they are. Please exercise real and serious caution when using either a strong base / acid. Use long sleeve rubber gloves, pants & closed toe shoes as well as eye protection. These chemicals will cause real and permanent damage if mishandled.
 

brewgasm

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I have an older model of the same brew bucket and this thread has just reminded me that I am overdue for passiveisation and a seal kit.

I wash with sodium percabonate (sometimes blended with sodium metasilicate)

Rinse Well

Fill to the top of the cone with phosphoric acid 1:2000 or the foaming sanitiser (I think its a knock off of star San) and use a spray bottle to keep applying a layer of foam down the sides.
 

RobW

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Can you over passivate?
I pull my fermenter and valves down after every brew, scrub off the visible soiling and then soak in percarbonate before rinsing with water.
I pray the valve components with Starsan as they go back together.
After reassembly I spray the interior of the fermenter with Starsan and leave it with the lid on until next use (effectively repassivating).
At that time I give it another spray with Starsan and then drain it before use.
The focus is on sanitising but there is incidental passivating - any issues with that?

Cheers
Rob
 

Meddo

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Where I work the Fermenters (well everything really) gets cleaned
Every Brew
Manually - hose and a scrubber to remove crud (Krausen ring, yeast sediment, crud on heating surfaces...).
Caustic Soda - 1.5-2% hot through the spray ball - seriously nasty
Rinsed - Clean water before use
Proxitane - Just before filling

Hot acid wash about once a month, used hot and strong enough to passivate the stainless as well remove any buildup of beer stone.
Before I used any new Stainless equipment I would clean with caustic (at home maybe something less aggressive) first to remove any oils then passivate it.
Don't know where you are located but if you have a local craft brewery have a chat with the guys there they can probably help you with some of the industrial strength passivating chemicals (usually a blend of Nitric and Phosphoric acids). Make sure you use to instruction.
Getting the surfaces clean and passivated before you use Stainless makes a big difference to how clean it stays, keeping beer stone under control will matter later. I've see some home conicals that looked like they had coral reefs growing in them, impossible to keep bacteria under control.
Mark
Hey Mark, have you got any recommendations for a specific CIP pump for your process described above? 1.5" sprayball in a 55L SS unitank is my use-case so probably a bit smaller than what you're doing I'm guessing, but I haven't been able to find anything to spec that doesn't come with an industrial-sized price tag.

Cheers,
 

Wobbly74

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I pray the valve components with Starsan as they go back together.
Not sure about over passivating, but I often pray when sanitising too :p

I've got a 26L stainless fermentation keg that I've not passivated in a long time. I usually spray it out and clean by hand, then dump hot wort into it, purge with co2 and invert to sanitise. Not sure if I should passivate more often than I do, but tbh haven't used it much lately...
 

MHB

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Ok a couple of point that need addressing.
Yes you could "over passivate". Passivation is really just using an acid strong enough to remove Iron (Fe) from the surface, but not the Chromium and Nickel, you are left with a Cr/Ni rich surface that better resists corrosion. By using some Phosphoric acid you form a surface of Cr/Ni Phosphate that is really tough and even more resistant than the metals alone.
Passivation is really important especially where the metal has been stressed by either working (bending and shaping) or heated as in welding or direct fired. Over time the surface becomes less protected and benefits from re-passivating but every treatment will remove some metal, do it too often and you have no metal... so once or twice a year is pretty common.

The other reason for using an Acid cleaner (usually the same or similar to passivating chemicals except for concentration and temperature) is to remove Beer Stone, which is a build up of mostly Calcium Oxalate. Beer stone is sort of rough and porous and provides a great home for bacteria.
In the beer cellar using Caustic isn't really enough on its own, we are are looking to remove different soils than those in the brewhouse (on big systems pumping hot caustic into a fermenter that hasn't been emptied of CO2 can be catastrophic vacuum imploding the tank), in most system Caustic followed by Acid cleaners are preferred, but not at passivating strengths.

Personally I doubt that Star San or similar is really strong enough to passivate stainless, there isn't enough Phosphoric acid and no Nitric which is really the workhorse of passivation. Even a little suspicious of its ability to tackle a heavy beer stone buildup. Probably OK for routine sanitation and perhaps to prevent growth of beer stone.
Don't pump high foam cleaners through a spray ball.
Good reasons to make sure you have enough Calcium in your water to precipitate the bulk of the Oxalate earlier in the process (over say 100ppm at end of boil).

On CIP pumps - sorry, for a spray ball to work well you need pretty massive flows (often the problem is getting the return out of the bottom of the tank fast enough - pissy little 1/2" plumbing isn't big enough), just had a quick look on eBay and found this one in a couple of seconds
Stainless Steel Food Grade Centrifugal Pump Sanitary Beverage Wine Pump 3T/h
750W Stainless Steel Centrifugal Water Pump Food Grade 120L/min WINE JUICE MILK

3T/H being 3,000L/h the second one being around 7,200L/h
Mark

PS
As above hot Caustic and Acids are bloody dangerous - I still have a scar from hot caustic, been there for over 30 years and not going away any time soon, so be very careful.
Little things like hoses coming off barbs, seals that don't, fine mist from spray getting in your eyes...
Thinking ahead, reading labels and taking care is cheap and fairly painless.
M

PPS
Citric acid isn't really up to the job, to work it needs very specific concentrations, some other chemicals added and a lot of time, not things most homebrewers will find easy to setup and use effectively.
m

Edit to Fix Link
 
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Can you over passivate?
I pull my fermenter and valves down after every brew, scrub off the visible soiling and then soak in percarbonate before rinsing with water.
I pray the valve components with Starsan as they go back together.
After reassembly I spray the interior of the fermenter with Starsan and leave it with the lid on until next use (effectively repassivating).
At that time I give it another spray with Starsan and then drain it before use.
The focus is on sanitising but there is incidental passivating - any issues with that?

Cheers
Rob
Phosphoric acid is not an acid used for passivating, nitric acid is the go to acid if you are looking to passivate s/steel if once you have cleaned your vessel leave it open to air the oxygen will react with the chromium to skin the vessel.
 

Meddo

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Ok a couple of point that need addressing.
Yes you could "over passivate". Passivation is really just using an acid strong enough to remove Iron (Fe) from the surface, but not the Chromium and Nickel, you are left with a Cr/Ni rich surface that better resists corrosion. By using some Phosphoric acid you form a surface of Cr/Ni Phosphate that is really tough and even more resistant than the metals alone.
Passivation is really important especially where the metal has been stressed by either working (bending and shaping) or heated as in welding or direct fired. Over time the surface becomes less protected and benefits from re-passivating but every treatment will remove some metal, do it too often and you have no metal... so once or twice a year is pretty common.

The other reason for using an Acid cleaner (usually the same or similar to passivating chemicals except for concentration and temperature) is to remove Beer Stone, which is a build up of mostly Calcium Oxalate. Beer stone is sort of rough and porous and provides a great home for bacteria.
In the beer cellar using Caustic isn't really enough on its own, we are are looking to remove different soils than those in the brewhouse (on big systems pumping hot caustic into a fermenter that hasn't been emptied of CO2 can be catastrophic vacuum imploding the tank), in most system Caustic followed by Acid cleaners are preferred, but not at passivating strengths.

Personally I doubt that Star San or similar is really strong enough to passivate stainless, there isn't enough Phosphoric acid and no Nitric which is really the workhorse of passivation. Even a little suspicious of its ability to tackle a heavy beer stone buildup. Probably OK for routine sanitation and perhaps to prevent growth of beer stone.
Don't pump high foam cleaners through a spray ball.
Good reasons to make sure you have enough Calcium in your water to precipitate the bulk of the Oxalate earlier in the process (over say 100ppm at end of boil).
On CIP pumps - sorry, for a spray ball to work well you need pretty massive flows (often the problem is getting the return out of the bottom of the tank fast enough - pissy little 1/2" plumbing isn't big enough), just had a quick look on eBay and found this one in a couple of seconds
Stainless Steel Food Grade Centrifugal Pump Sanitary Beverage Wine Pump 3T/h
750W Stainless Steel Centrifugal Water Pump Food Grade 120L/min WINE JUICE MILK

3T/H being 3,000L/h the second one being around 7,200L/h
Mark
PS
As above hot Caustic and Acids are bloody dangerous - I still have a scar from hot caustic, been there for over 30 years and not going away any time soon, so be very careful.
Little things like hoses coming off barbs, seals that don't, fine mist from spray getting in your eyes...
Thinking ahead, reading labels and taking care is cheap and fairly painless.
M

PPS
Citric acid isn't really up to the job, to work it needs very specific concentrations, some other chemicals added and a lot of time, not things most homebrewers will find easy to setup and use effectively.
m

Edit to Fix Link
Thanks for the reply Mark, that one doesn't have any specs listed about temperature and corrosion resistance though - from enquiring about similar pumps with suppliers it seems like if those specs aren't listed it means they're not going to have any significant resistance. The best I've found so far in semi-affordable dollars is this one, but I'm not too sure whether it's a smart idea buying a pump from China and not having local support for it.

https://www.aliexpress.com/item/MKP...nt-Chemical-Pump-For-Hot-Oil/32793572600.html
 

captnhaddock

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PS
As above hot Caustic and Acids are bloody dangerous - I still have a scar from hot caustic, been there for over 30 years and not going away any time soon, so be very careful. Little things like hoses coming off barbs, seals that don't, fine mist from spray getting in your eyes... Thinking ahead, reading labels and taking care is cheap and fairly painless.
M

I just want to second / third and fourth this. Caustic is no joke! (see my comment further up the thread)
 

MHB

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Thanks for the reply Mark, that one doesn't have any specs listed about temperature and corrosion resistance though - from enquiring about similar pumps with suppliers it seems like if those specs aren't listed it means they're not going to have any significant resistance. The best I've found so far in semi-affordable dollars is this one, but I'm not too sure whether it's a smart idea buying a pump from China and not having local support for it.

https://www.aliexpress.com/item/MKP...nt-Chemical-Pump-For-Hot-Oil/32793572600.html
It says 2 phase, check on that, otherwise it looks OK, impressive amount of suction head which can cause problems with cavitation when pumping hot liquids.
On buying from China, its cheap V quality at very high price we all take a punt occasionally

Mark
 

Meddo

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It says 2 phase, check on that, otherwise it looks OK, impressive amount of suction head which can cause problems with cavitation when pumping hot liquids.
On buying from China, its cheap V quality at very high price we all take a punt occasionally

Mark
Yeah I was wondering about the "2-phase", any idea what that means? I'm no leccy engineer but I've only heard of single- and three-phase, I thought maybe they meant it's a two-stage pump rather than two-phase electrically.

My hot side drainage is all 1.5" and the unitank is 2" so I don't have any real concerns about keeping fluids up to the inlet, there is a 0.37kw version available as well though.
 

RobW

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Phosphoric acid is not an acid used for passivating, nitric acid is the go to acid if you are looking to passivate s/steel if once you have cleaned your vessel leave it open to air the oxygen will react with the chromium to skin the vessel.
The SS Chronical setup instructions recommend Starsan to passivate before use (maybe because it's readily available?).
Linky

From what Mark says it doesn't seem like it's an issue in any case.
 
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The SS Chronical setup instructions recommend Starsan to passivate before use (maybe because it's readily available?).
Linky

From what Mark says it doesn't seem like it's an issue in any case.
Not an issue, the passivation from using Starsan is not actually from the Starsan but from the air (quote
if once you have cleaned your vessel leave it open to air the oxygen will react with the chromium to skin the vessel.) What you have been doing is fine.
Uses for phosphoric acid with stainless steel
Phosphoric acid is used as a chemical-cleaning agent for stainless steels.
It is used in commercially available stainless steel cleaning preparations and so if used in accordance with the manufacturers / suppliers instructions will not etch or corrode the steel surface.
Phosphoric acid is not considered to be a 'passivating' acid but the clean surface left after treatment should allow the stainless steel to naturally self passivate.
 

MontPel

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Not an issue, the passivation from using Starsan is not actually from the Starsan but from the air (quote
if once you have cleaned your vessel leave it open to air the oxygen will react with the chromium to skin the vessel.) What you have been doing is fine.
Uses for phosphoric acid with stainless steel
Phosphoric acid is used as a chemical-cleaning agent for stainless steels.
It is used in commercially available stainless steel cleaning preparations and so if used in accordance with the manufacturers / suppliers instructions will not etch or corrode the steel surface.
Phosphoric acid is not considered to be a 'passivating' acid but the clean surface left after treatment should allow the stainless steel to naturally self passivate.
What sort of time scale will the oxygen passivate a clean (dry?) SS surface? Minutes? Hours?
 

Coalminer

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The SS Chronical setup instructions recommend Starsan to passivate before use (maybe because it's readily available?).
Linky

From what Mark says it doesn't seem like it's an issue in any case.
The SS Brewtech instructions also say to use Starsan at X5 the normal dosage i.e. 7.5ml/Litre
 

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