Funny taste

[MickDundee]

This has got nothing to do with the flavour.
BUT
In my understanding, a beer engine draws beer up from a non-pressurised cask and dispenses it into the glass, while a corny keg is pressurised and quite unsuited to a beer engine.
SO
DId you dispense the beer from the cornie or the small barrel with your beer engine?

You can use a corny with a beer engine. I have a Pint365 engine, I use a demand valve to stop it pushing the liquid from the corny through the pump when it’s off, and o have a secondary regulator set at 2PSI to keep the carbonation “real ale style”.

 

[cushyno]

You will have to passivate the keg, that is what your problem is. The kegs have to be passivated periodically. You will need to give it an acid wash and the air will passivate it.
http://beersmith.com/blog/2017/01/0...-beer-brewing-equipment-to-prevent-corrosion/

Thanks for the link @foxy . And thanks @Oscar Mild for asking the question. You may have solved a mystery for me. A couple of my beers have tasted a little metallic. It may have been from scrubbing my basic heating element with wire wool and not passivating.

 

[The-Engineer-That-Brews]

scrubbing my basic heating element with wire wool

Could well be! Scrubbing stainless with wire wool or even stainless steel wool is (in my understanding) a problem because of iron-to-iron affinity which can even make it rust

From John Palmer's 'how to brew' appendix B : (interestingly he seems to suggest you don't need an acid wash for re-passivating):

A situation that often comes up is, "Hey, my stainless steel is rusting! Why? What can I do to fix it?"​

​

Stainless steel is stainless because of the protective chromium oxides on the surface. If those oxides are removed by scouring, or by reaction with bleach, then the iron in the steel is exposed and can be rusted. Stainless steel is also vulnerable to contamination by plain carbon steel, the kind found in tools, food cans, and steel wool. This non-stainless steel tends to rub off on the surface (due to iron-to-iron affinity), and readily rusts. Once rust has breached the chromium oxides, the iron in the stainless steel can also rust. Fixing this condition calls for re-passivation.​

​

Passivating stainless steel is typically accomplished in industry by dipping the part in a bath of nitric acid. Nitric acid dissolves any free iron or other contaminants from the surface, which cleans the metal, and it re-oxidizes the chromium; all in about 20 minutes. But you don't need a nitric acid bath to passivate. The key is to clean the stainless steel to bare metal. Once the metal is clean, the oxygen in the atmosphere will reform the protective chromium oxides instantly. The steel will nearly as passivated as if it was dipped in acid. Nitric acid passivation creates a more chromium-rich passive surface, but is not necessary for brewing use.​

​

To passivate stainless steel at home without using a nitric acid bath, you need to clean the surface of all dirt, oils and oxides. The best way to do this is to use an oxalic acid based kitchen cleanser like those mentioned above, and a non-metallic green or white scrubby pad. Don't use steel wool, or any metal pad, even stainless steel, because this will actually promote rust. Scour the surface thoroughly and then rinse and dry it with a towel. Once you have cleaned it to bare metal it will re-passivate itself.​

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If you have straw-colored or bluish tinted oxides on the stainless from welding or soldering, it should be cleaned off with a scrubby and cleanser before use. The colored oxides are not passive and will lead to rusting of the stainless steel if not cleaned. You should not have to do this procedure more than once, but it can be repeated as often as necessary.​

 

[cushyno]

@The-Engineer-That-Brews thanks for this. I scorched my element once and it never fully came up bright and shiny since then, always a bluish tinge to it where the scorching was, same blue as you'd get chasing colours when tempering steel. This info suggests scrubbing until all oxides are removed, which nigh impossible to do without wire wool or something more abrasive than a green pad. Do you reckon it needs to be thoroughly sanded/scoured before passivating?

 

[The-Engineer-That-Brews]

same blue as you'd get chasing colours when tempering steel

Blimey, that takes me back to my school metalwork :-) I used to love doing that...

nigh impossible to do without wire wool or something more abrasive than a green pad

Yes I know what you mean... I'd suggest some acid then. If you get some Picking Vinegar from the supermarket (it's stronger than the normal stuff) and use it hot, or you could even try a bit of AML/CRS (it's a mix of sulphuric and hydrochloric).

If neither of those options work then use some Pink Stuff - it's just powdered quartz so should be fine on stainless steel :-)

 

[cushyno]

Never heard of pink stuff. I think I'll go for this regime for the element:

1. Oxy cleaner
2. Scrub with scouring pad
3. Soak in 5x strength star San for 30 mins
4. Air dry and leave for 8 hours
5. Rinse thoroughly

That's got to help. If that doesn't work I'll consider stronger acid after next brew.

I'll probably do a couple of cornies I have empty while I am at it, then dilute the starsan back to regular strength for rinsing and store for general use.

 

[The-Engineer-That-Brews]

It's pretty flipping good - basically just very fine grinding paste (like jewellers rouge)

 

[The-Engineer-That-Brews]

Not to be confused with Red Stuff...

 

[Oscar Mild]

Thanks everybody for your help, top notch as ever.