Carbonic bite, pressure fermentation & kegging help

[Elliott 22]

Hey everyone I have been pressure fermenting and kegging for a few months now and kept getting a bitter flavour (metallic) in my beer,

I have reconditioned kegs and after my first couple of beers had a metallic taste, so when I kicked the keg I checked the inside of the kegs and when cleaning were coming out with grey dirt on the cloths (machine oil)

So cleaned with sodium percarbonate washed through disassembled and used bar keepers friend on everything washed out and let passivate for 3 days before sanitising with chemsan.

This made a big difference but was still getting some off flavours and have been trying lots of different things, deep clean fermzilla taps, lines etc.

Then finally yesterday I think i have got to the bottom of it :-

Carbonic bite, my beer didn’t seem over carbed but after venting pressure when warm and dropping my serving pressure Down to 6psi the flavour has gone!

I have been fermenting at pressure for the style and temp from dr Hans carbonation calculator and then close transferring and bring psi back up to the carbonation chart level, last beer was a golden ale so 2.2vol at 25psi.

I would then leave for a week or 2 to condition at room temp then put in kegerator and attaching to co2 at 12psi serving pressure.

I can’t see where I have been going wrong? Is it due to fermenting under pressure I don’t need such a high serving pressure or is it the amount of co2 I’m fermenting at?

Also my regulator is a brand new odl regulator not cheap, so can’t see it being out.

Any help greatly appreciated

 

[Marko85]

I had the same issue regarding lots of metal dust inside a reconditioned keg. Tried all the usual brew cleaners/chems but found in the end that sugar soap was the only solution to really shift it. I'm interested in why you have chosen to carbonate/condition at room temperature and not just go straight into the kegerator at lower pressure? Also what pressure are you actually fermenting at?

 

[Elliott 22]

I had the same issue regarding lots of metal dust inside a reconditioned keg. Tried all the usual brew cleaners/chems but found in the end that sugar soap was the only solution to really shift it. I'm interested in why you have chosen to carbonate/condition at room temperature and not just go straight into the kegerator at lower pressure? Also what pressure are you actually fermenting at?

Normally due to having a keg about to kick and trying to allow the keg to reach its peak before serving, I’m fermenting at the carbonation chart style so was at 25psi naturally rising from the fermentation.

 

[Marko85]

Right okay, I'm really brand new to pressure fermenting so could be completely wrong however from my research 25psi during fermentation seems high. I ferment at 10psi regardless of style then crank the pressure according to the charts post fermentation. Maybe you are carrying forward lots of carbination from the initial fermentation then maybe over carbing in your serving keg?

 

[Elliott 22]

Right okay, I'm really brand new to pressure fermenting so could be completely wrong however from my research 25psi during fermentation seems high. I ferment at 10psi regardless of style then crank the pressure according to the charts post fermentation. Maybe you are carrying forward lots of carbination from the initial fermentation then maybe over carbing in your serving keg?

Thanks @Marko85
I am thinking this could be the case although I do drop pressure for my closed transfer but then re-pressurise to 25psi or whatever the style dictates at my ambient room temp which was 22c.

mom wondering how much the beer is already carbed to during the fermentation even tho warm