Mini Keg Discussion / Mods / Show Off - Dedicated Thread

[gezzanet]

Yeh it is disappointing that it seems to be the steel/welds thats the cause. and will be chasing it up with the manufacturer, thankfully for most it isn't an issue, but extremely unlucky for a couple with the issue, and those ones need to be replaced.

I think I've got the same issue. See post515

Moving house so all packed up and won't see it for another 4-5 weeks

Only used 1 of the 2 so far.

 

[RdeVjun]

What's to take home mate? Sodium percarbonate is sodium percarbonate. The question should be concentration and contact Time. I wasn't saying that it's the wrong thing to do to allow sodium percarbonate to come into contact with stainless steel just sharing my experience and understanding in this Discussion

That isn't quite what you said earlier, while I don't think its got anything to do with concentration or contact time either, perc simply isn't reactive with stainless.

If there's something that many of us have been doing wrong all this time then it would be great to understand why that might be the case. I sense though that there simply isn't any problem, that's certainly been my experience and is that of many others.

Its no biggie mate, helps inform the debate and understanding and all for the greater good.

 

[Zorco]

So, trying to summarise what I've picked up:

the hypothesis for the beer discolouration is more or less a type of corrosion relating to poor welding skill / ingredients / process known as 'sugaring'

iron oxide, chrome oxide, nickel oxide production in an oxygen environment. Probably expected that purging with argon would be skipped to save money

 

[peteru]

I left the minikeg to dry out. Took a peek inside with a torch and it looks hazy and much darker than any of my full size stainless steel kegs. Even the ancient Coca-Cola ball-lock converted kegs look brighter inside than the minikeg. I did a second pass of the uncooked rice and water shake clean and this time it came out only slightly discoloured. Not clean, but not a filthy mess either.

I don't think I have enough information to be sure if it is the welding or the "stainless" steel itself. I suspect that it may be the steel. I recall reading somewhere that if the passivation process is not done correctly, it will result in something similar to what I'm seeing. I'd like to find out if there is a way to permanently fix the issue at home with some readily available products, for example a rinse with undiluted Starsan or with citric acid. It would be good to get a metallurgist or someone with the understanding of the chemistry involved.

 

[damoninja]

perc simply isn't reactive with stainless

It wouldn't want to be I left perc in a corny for a month once h34r: h34r:

 

[wide eyed and legless]

Question does need to be asked. What's the story??

Google mini kegs blackening, metallic taste, weld faulty, etc the links lead back to AHB we are only a small market hundreds of thousands leave China each year destined for the bigger markets of Europe and America, how come they don't have the problems over there.
The welding examples shown here are from TIG, not PAW, which will give a by far superior weld and and minimal chance of oxidising
If it's anything to do with quality control the problem would be more widespread than Australia, but the only complaints are coming from here.

 

[Zorco]

I have made contact with the Australian Stainless Steel Development Association and an industry expert will call me back.

My line of query will include

their awareness of Stainless from China for mini kegs;

Stainless products fabrication issues leading to the outcomes put forward by us;

People in industry that can perform accurate testing of Stainless products to determine their grade and composition;

Remediation options for 'sugaring' type of corrosion and any advice on health impacts of consuming oxides.


Just taking this up a notch.

Redman9's comment bothers me.

Will keep you updated

 

[GoodDuck]

Umm yeah, I can confirm peteru's technique.
This 2L mini-keg had spent approx 24 hours soaking with sodium-perc, and then 24 hours soaking with StarSan.
Then performing the uncooked rice trick resulted in a glass of water with similar colour to peteru.

Using my middle finger to rub around the inside conical top, I can reach side top weld seam with the tip of my finger.
The tip of my finger comes out black with this unit, which would suggest the seam is the cause of the issue

 

[Zorco]

A primary school class action screen play.

 

[Liam_snorkel]

FMD, GoodDuck's photo is disturbing.

 

[Grott]

This is not good and suggest many a pissed off recipient. Am I right in thinking with this particular bulk buy not everyone has this problem?
Concern now has to be the current bulk purchases that should be about here.

 

[mtb]

So what you're saying is, these kegs are..

I couldn't help myself and Zorco was taking all the metal references.

 

[barls]

its a shame that its

 

[peteru]

If it's anything to do with quality control the problem would be more widespread than Australia, but the only complaints are coming from here.

Why is that suspect? Is it not possible that the manufacturer used a cheap and nasty batch of steel for this production run? Is it not possible that some kegs were passivated with a contaminated bath? Just those two issues alone, together with poor QC could result in one batch or part of a batch being bad.

As far as the complaints, it took a while to discover and identify the problem. There were some reports of off-flavours a little while ago from some people. It took me months to discover the discolouration. What's to say that even if the problem was present globally that only a few people here in Australia figured out the underlying issue and how to make it manifest in a very obvious way?

I guess my point is that absence of complaints in other markets does not imply absence of problems in those markets. It certainly doesn't preclude this being an isolated incident.

 

[Batz]

Well I am now just a little concerned, I own 4x 5lt ones two from the first BB and two from the second. Also a 2lt one from I Kegger.

Tonight I will do the test on all of them. One closer inspection and one of the 5lt kegs has a weld around the inlet tube, just above the conical, looks like a possible repair?

Fingers crossed for a good result.

See LiquidGolds post #632. Only one of my kegs has a weld visible like this, others are undetectable.

Batz

 

[peteru]

Am I right in thinking with this particular bulk buy not everyone has this problem?

Not enough data to make a call on that. The patented "peteru Rice Rinse Test"TM is easy and cheap enough to perform, if you want to discover how your minikeg fares. Just about everyone will have the required materials.

1. Clean minikeg using your normal process.
2. Add one or two tablespoons of uncooked rice.
3. Add 300mL of clean water.
4. Seal keg and shake vigorously for 5 minutes, while turning so that all surfaces are "washed" by the rice.
5. Pour cleaning liquid into a glass.

On the first pass, I got almost black, metallic looking liquid. On the second pass, the liquid was milky white with light gray-blue discolouration.

I think my next step is going to be to put some shit beer into the minikeg (like Boags Premium that the father-in-law left here) and let it age for a few weeks. ( Serve it to him next time he's around - I doubt he would notice the difference ;-) ) I'll keep one bottle to compare the colour side by side, then, when the beer is gone, do the "peteru Rice Rinse Test"TM and see how it comes out. I guess this will show whether the contamination is a once off film that can be removed, or whether it's an ongoing chemical process that will keep on coming back.

 

[malt and barley blues]

Are we sure that it isn't Starsan that is the culprit here, I noticed on the Beerkat thread that someone had left their taps on for a 24 hours rinse in starsan and the internals discolored where the Starsan had pooled, Starsan is a 2 minute rinse I believe.

 

[peteru]

Advice on Starsan varies from 30 seconds to 2 minutes contact time. For most of my use, it's usually in that time window. Spray / splash, drain and either rinse with filtered water or fill with product.

However, I don't think Starsan is causing the issue. When I did the second "peteru Rice Rinse Test"TM , I left Starsan in the minikeg for about 5-10 minutes and it didn't seem to cause additional blackening. Even if Starsan was an issue, you would have the same problems with beer. Beer pH is still low enough (in the 4 range) to cause acidity related chemical reactions.

 

[mtb]

I use a stainless corny keg to store my starsan and there's no discolouration afterwards.

 

[malt and barley blues]

But the same problem has occurred in the Berkat buy so it isn't limited to the bulk buy.