Mini Keg Discussion / Mods / Show Off - Dedicated Thread

[Zorco]

Some interesting preliminary data on the keg corrosion issue.

83.3% of registered faulty kegs (From ATHB) were purchased in MKII. A few from Beerkat.... When were they bought approximately? - Might be good to correlate when Beerkat ordered them from the supplier and see if it aligned with the MKII order.

This is not conclusive, but a tiny trend which we will keep reviewing.


AND IT DOESN'T FOLLOW THAT EVERYONE IN MKII WILL HAVE A PROBLEM.

It might have been one unskilled dude on the production line from a team of fabricators.... Maybe he didn't know the argon tank was empty and purging was simply not happening.

All guesses, so nothing to conclude........

 

[mstrelan]

BK keg purchased late Jan this year.

 

[Zorco]

Rice test done and result is CLEAR. Just yeasty beer residue from nat carbing. Hmm it was a Saison that was quite clean flavour, not sure maybe it just was mentally 'tinny'

The industry expert said that only a few ppm will cause a problem for flavour. When your keg is rinsed maybe give it a dose of sodium percarbonate - oxidise whatever iron is vulnerable and do the Trademarked rinse again.

I'll invite you to the PM anyway mate, feel free to register your suspect keg if / whenever you feel like it.

Which bulk buy did you get that one from? [MKI; MKII; MKIII]?

 

[Jack of all biers]

The industry expert said that only a few ppm will cause a problem for flavour.

NHMRC Guideline Value's have Aesthetic values for Iron at 0.3 ppm. Essentially anything higher than that will be tasted. My opinion is that 0.2 ppm or higher can be tasted by some, but this is more anecdotal than evidence based. Note that this is for Iron, not Iron Oxide or other Oxides, but I'd suggest it would be similar.

EDIT - Just re the whole magnet test. I know that Lyrebird_cycles has already alluded to this, but as some have still be using magnets as some sort of test indicator. From wikipedia.

Chromium dioxide or chromium(IV) oxide is an inorganic compound with the formula CrO2. It is a black synthetic magnetic solid.[3] It once was widely used in magnetic tape emulsion.[4] With the increasing popularity of CDs and DVDs, the use of chromium(IV) oxide has declined. However, it is still used in data tape applications for enterprise-class storage systems. It is still considered by many oxide and tape manufacturers to have been one of the best magnetic recording particulates ever invented.

 

[nosco]

I got this inspection camera from Bunnings for about $35 I think to check a problem with our plumbing. I have been trying to find it. Sorry for the crap camera work but Im using a coat hanger wire to control it.

Edit: cant upload atm but there is clearly rust on the inside top of the keg. Near the weld and also on some scratches. Ill try and put it on Youtube and post but the internet is a bit slow.

 

[nosco]

Finally got it working. I have only used this keg a few times because a faulty reg so it has been cleaned with perc and stored with a starsan solution. Im the wrong person to be making any conclusions from this but I would have thought that the starsan would passivate the stainless. The rust spots at the end could maybe be fixed by re-passivating. Its hard to see the weld in the light but Ill have a go at it with some Tricleanium and starsan when I get the time. I hope the vid helps.

https://www.youtube.com/watch?edit=vd&v=AqVfzvBB1vo

Edit:the camera is a usb camera from the plumbing section at Bunnings about $35. The vid is of the inside of the top of the keg.

 

[peteru]

Finally got it working.

Computer says: No.

 

[Zorco]

Just added you to the PM nosco. When your photos and vids are all good, please upload them to the google drive.

 

[bradsbrew]

I cant accept that a product sold as 304 will hold a magnet. This is a 1.89L BK keg , holding a folded envelope, thats 4 sheets of paper and folded again, thats 8 sheets thick and still holding.
Showed this to my BIL yesterday, in over 20 years of fabricating SS he has never seen a magnet hold on 304 SS.

 

[peekaboo_jones]

Thanks Zorco, no worries I shall have another crack today.
Kegs purchased from bb MKIII.

Slightly off current topic feedback: I have 2 mini regs and work perfect every time, just using the small bulbs

 

[wide eyed and legless]

Reading the link from mbb the stainless becmes magnetic after being worked, rolled, pressed, folded etc.

 

[bradsbrew]

Reading the link from mbb the stainless becmes magnetic after being worked, rolled, pressed, folded etc.

Read a few articles as well. Tried the same magnet on cornie kegs, old brewery kegs, all my brew pots and another BK 5L keg and it did not stick, not even keg king products, which was a nice surprise. Assuming the mini kegs go through the same manufacturing process, surely it is a different metal?

 

[wide eyed and legless]

Try the magnets on the kitchen sink.

 

[bradsbrew]

Try the magnets on the kitchen sink.

Not sure if the sink would be 304? Maybe 301 or a 400 type?
Tried it anyway. Magnet only holds to bends and folds, not on flat parts and the hold is not as firm as it is on the keg.

 

[wide eyed and legless]

The sink is 304 and the magnet is sticking where it was formed, a bit like work hardening but work magnetising.
Would be an interesting exercise for say a 4 litre Beercat and a 4 litre from the bulk buy to be measured and the dimensions checked against each other. If it came from the same tooling they would match and then it would give an indication whether they came from the same manufacturer.

 

[Coalminer]

Well the 2L kegs and 5L kegs that I have are different to each other
the 2L kegs are very magnetic on the main body and the top and bottom as well as the welds and handle
the 5L kegs (bought in the same bulk buy) are not magnetic apart from around the welds
So I would assume (I know I shouldn't) that they are different grades af metal to start with
I don't know if this is a proper way to prove quality and also may depend on how strong the magnet is
I have used a magnet out of a hard drive and testing around the brewery I have found magnetic areas in the following:

10 x 19L Cornies
3 x 9L Cornies
2 x 30L Aginox Olive oil drum fermenters
2 x 15L Aginox Olive oil drum fermenters
1 x 20L Braumeister
and various other equipment, spoons, funnels etc
The caps and head units are not

all this is mainly where the metal has been rolled or welded

But surprisingly the taps that came with the kegs are also magnetic. So if they are chrome plated brass then whats that about?

 

[Zorco]

I cant accept that a product sold as 304 will hold a magnet. This is a 1.89L BK keg , holding a folded envelope, thats 4 sheets of paper and folded again, thats 8 sheets thick and still holding.
Showed this to my BIL yesterday, in over 20 years of fabricating SS he has never seen a magnet hold on 304 SS.

We are going to send a sample to the lab and find out

 

[nosco]

Computer says: No.

It works with Chrome on my PC but not on the phone app.

 

[Grott]

I use 9.5 & 12 litre keg sets. 4 Chinese 9.5l & 3 x 12l are not magnetic. 2 x 12l &
1 x 9.5l Italian kegs (meant to be the best and are Imo) are magnetic.
I have not had any problems with any of these kegs.

 

[nosco]

It works with Chrome on my PC but not on the phone app.

Ok. The video was set to private on youtube. It should work now :unsure:

 

[Zorco]

Works on the Mac. No worries

 

[nosco]

I sometimes get rust spots on my brew kettles like the ones at the end of the vid so thats maybe not a huge concern if i can get rid of them. I would'nt know what to make of the spot near the weld or the weld itself.

Would citric acid work better as a passivator(?) than starsan?

 

[Jack of all biers]

Finally got it working. I have only used this keg a few times because a faulty reg so it has been cleaned with perc and stored with a starsan solution. Im the wrong person to be making any conclusions from this but I would have thought that the starsan would passivate the stainless. The rust spots at the end could maybe be fixed by re-passivating. Its hard to see the weld in the light but Ill have a go at it with some Tricleanium and starsan when I get the time. I hope the vid helps.
...
Edit:the camera is a usb camera from the plumbing section at Bunnings about $35. The vid is of the inside of the top of the keg.

Not sure on your welds, as they are hard to see, but where the obvious rust is are some fairly clearly defined scratch marks from machining. Cleaning with acid and re-passivation should work on these, though you will likely need to re-passivate every now and then as crevices tend to gather corrosive substances that will eventually lead to further rust over time.

EDIT - Nosco, just saw your post at #862. Citric acid is a more economical passivator than starsan (price wise) at the right concentration and temp should wash away the contaminants so that passivation can take place. There are a few commercial SS passivation solutions that use Citric acid, so you are on solid ground and it is a lot less dangerous (for you and the waste water) than nitric/fluoric acid solutions.

 

[Coldspace]

Well I thought I would add my discoveries, good for me so far...... maybe, and this is not knocking the good work from others or the bad luck from others as I may still have ticking time bombs.....

I bough 4 x 5 ltr kegs bulk buy 2. Cleaned with percarbonate soak for 1 hour then rinsed with water. I spray light starsan only if filling and leaving full for more than a few days like nows trip for easter, for bbqs over night I usually just rinse the mini with hot water then fill.

Ive used them solid last Christmas for 3 weeks. most of the time they carried beer for 1- 2 weeks. Ive used them over past several months sporadically for local social events including leaving beer fo upto 2 weeks in them, still no issues.
watching this thread has made me anxious that ive got sus ones but at this stage I'm still happy with them.
Ive kegged up some brews filled from my primary stocks for easter camp next week, these were filled to the absolute neck, under pressure till foam leaked out of the pressure valve 6 days ago. and I tested a pot of these today to make sure I wasn't dragging crap beer away, all tasted and appeared exactly the same as the ones in my primary cornies, so I'm either one of the lucky ones or I got kegs from the Monday/Tuesday welder and not Fridays one
pictured is my lovely crisp rice lager and my LC pale ale abit darker due to the crystal , I also had my 3 rd mini yesterday filled with my nelson sav lager which I took to a friends house last night which dispensed amongst a few and was great and the same as the mother keg at home and no one knew any diff.

I feel for you guys after watching things unfold and hope at the same time mine don't fail in the next few years as one would hope at least a decade of use with stainless or more...
I'm still following this like the rest of yous
I have not tried the rice rinse test on these and my 4 th keg is full with a stout and I'm taking these all away next week , so I hope mine don't fail soon otherwise Ill be pissed lol


my mini reg has been OK with adjustments but does leak the bulbs out fast which I'm sure is an internal leak. BTW it has no serial number so its prob a dud anyway..

Carry on the good works guys, not taking anything away from this thread , just adding my observations with my gear, maybe it was poor workmanship on some and not others?

Edit". My minis are slightly magnetic in the rolls and bottom and non magnetic that I can feel in the sides and are marked beer can..

Another idea, is that I got mine from bulk buy2 , but maybe mine were made at an earlier date or later than some others and all shipped at the same time????
Cheers

 

[nosco]

Maybe OT but how does TSP differ from vinegar and citric? I realise its an alkaline cleaner (it is isnt it?). My current method to passivate my SS is to use TSP and then use starsan in stead of citric. So if we are talking about removing rust with vinegar or citric how would TSP work and how would temperature affect it?

 

[peteru]

TSP is mainly a degreaser. You use it first to clean the surface before passivation with an acid based solution.

 

[Bones99]

Alrighty,

I've just knocked up a spreadsheet to track this issue, A good idea from earlier.

A five second memory dump has about 5 people which I've invited. If you have an issue with your keg regarding metal taste, darkening of your beer etc. let me know and I'll add you to the PM.

Try and fill in all the fields as it may help with tracking a bad batch.

Hi Zorco, add me into the spreadsheet too thanks

 

[Parks]

Hi Zorco, add me into the spreadsheet too thanks

Me too please mate. Mine is from the third buy I think and I get a lovely black smear when I run my finger inside the 4L one

My 2 iKegger growlers are also bad but I'll contact them directly.

 

[Jack of all biers]

So, I finished the metallic tasting keg tonight and rinsed it out with hot water only. Rubbed my fingers on the inside of the neck weld and smooth as a baby keg should be. Rubbed a bit further in and around the top cone part and pull my fingers out. First photo is with the flash, second without.



It looks like a greasy film and after washing my hands thoroughly with soap, the black has remained in the recesses of my finger prints. It didn't have an oil type odour nor feel oily, but sure did shine like oil. The beer had a bit of a sharp after taste that hung on the tip of the tongue, but mostly the only taste was iron/metallic exactly like when you cut your lip and taste blood.

This has got me stumped as the welds I can see and feel are smooth and clean. I can see some scratch marks on the base (similar to Nosco's video, but no rust). I will get a mirror small enough to get in the thing and have a better gander at the top welds, but I have the feeling mine is minor and probably needs a better clean job to get rid of reside crud from the various acid washes and bathes it would have gone through in the factory to clean it up.

 

[peteru]

I've done a trial "electropolishing" run experiment. I put electropolishing in quotes because I have no clue if I'm doing it right or if it is actually electropolishing or just a similar process with observable results, but here it goes.

The test vessel is a stainless steel cooking pot that was at one stage left on the stove and boiled dry on maximum heat. This caused a black oxide layer on the bottom of the the pot that could not be cleaned with vinegar, caustic soda, trisodium phosphate or an abrasive cleaner, such as Jif.

For my test, I used a 12V / 1.5A DC power supply (from an external Seagate HDD), with the positive terminal hooked up to the pot and the negative terminal connected to a stainless steel (I think) bolt. In order to judge the effectiveness of the process, I tilted the pot so that only half of the surface was subject to the process. I used white distilled vinegar with additional extra citric acid, heated to 70-80C, as the electrolyte. The surface was treated for about 15 minutes. To have a control, I subsequently rotated the pot 90 degrees and left it subjected to the heated electrolyte for about 20 minutes without any current being applied.

The results are encouraging. There is a visible reduction in the blackening of the pot where the "electropolishing" took place. The control segments with just the hot acid show no visible improvement.