Off flavoured Grainfather brews

[Fletch]

Thanks Kev. I had exactly the same problem with the spring, a few brews ago. Imake don't mention it in the cleaning procedure. I now know to dismantle it after every brew. It caused a horrible antiseptic taste and made the beer undrinkable. This time, the beer's not completely undrinkable, but it isn't pleasant.
I always clean the fermenter after use, and sterilise it with Starsan,immediately before pumping the next brew in. That's why I'm leaning towards the Grainfather or the hop spider as the cause of the infection. I don't think it's old grain as someone suggested, as it was a recently bought all-grain kit from Brew UK.

 

[henteaser]

It caused a horrible antiseptic taste and made the beer undrinkable.

You also mention the taste of "TCP" in an earlier post. These antiseptic/medicinal off-flavours are usually due to the presence of chlorophenols in the finished beer.

This is produced when phenols (produced naturally by the yeast) interact with chlorine/chloramine from any residual chlorine-based cleaning products or the original water source.

Maybe one to think about and rule out before you get too far down the "infection" rabbit hole!

 

[JapanBrew]

Try another batch but add a campden tablet to your mash water.

 

[Fletch]

Thanks guys, I really appreciate your help. I always put half a crushed Camden tablet in to the combined mash and sparge water the night before brew day. I then set the timer to heat it to mash temperature, ready for next day. I pump out the sparge water into a hot liquor pan, and then heat it up to sparge temperature whilst mashing.
Should that procedure get rid of the chloromine?

 

[henteaser]

I always put half a crushed Camden tablet into the combined mash and sparge water the night before brew day

Yep, for a standard 5 gallon batch that's plenty. So I'd be tempted to rule that out. Are any of the cleaning products you use on the fermentor chlorine or bleach based? If you can rule this out too, it can only really be down to a wild yeast creating a phenolic taste.

Some other things to consider;

- Are you using plastic fermentors? If so, are there any scratches or in the surface where bacteria/yeast could be harbouring?

- Was the same fermentor used for the 2 batches in question?

- You mention the rogue piece of malt husk in the GF's malt pipe, but you say you now take care to clean this. So was it the very next brew you had the same off-flavour? (That in itself would suggest it wasn't the trapped malt that was the original problem if it wasn't present in the very next batch).

- Have you taken the pump apart recently? I would add that to your cleaning routine for now while you're hunting down the culprit!