Kegging off flavours

[Cain Harland]

Quit often when I first tap a keg it tastes like crap. Its a flavor I have trouble describing it dank and chemical maybe. I usually suspect something is wrong with the hops and its something I don't notice when I have a taste during kegging. I have discovered if I let off a bit of gas and give it a day or two and it improves a lot.

My fermentation process is primary for 2 weeks with blow off pipe (rather than airlock) in the bottom of a 1L rum bottle filled with water and sanitizer. Cold crash for 1 week. Transfer to keg with CO2 blanket. Then carbonate at serving pressure for 2 weeks.

I wonder if its some fermentation by product that evaporates when using an airlock is kept in by the back pressure with the blow off pipe. Its the only explanation can think of but I know folks get good results with pressure fermenting. Any ideas?

[Peter Smith]

Ok so oxidation won't go away it will just get worse...as do most infections.  I put my money on the carbonation process and carbolic flavours...  the beer wont have "body" until it equalises...   your answer may be to wait a while

I don't know how others do it, I can never get carb right in under 2 weeks.  The exception being my brand new 9L kegs..  maybe I have leaks in my 19L ones.

[Peter Smith]

As an observation it seems the best pint is always the last one....

[Cain Harland]

Unfortunately for me the last few pints ended up on the garage floor after my 3 year old opened the tap.
Thinking about it at least 1 of the other beers with the same problem had a lot of Simcoe too so maybe it's a bit of carbonic acid mixed with the harsh, dank, cat pis from over / misuse of simcoe.

[Kevin Sharp]

I was thinking that might leave your dip tube full of air which is then compressed for a couple of weeks. The beer in the dip tube won't be very mobile so you could get some localised oxidation in there that will come out with the first pour. This however assumes that you don't fill through the dip tube and leave it full of beer.

[Cain Harland]

So this beer came right in a big way. It took 6 weeks in the keg but its great now. I think there was defiantly some of the harsh, carbolic thing Peter mentioned. But also simcoe seems to be a common factor in the beers I've had this problem with and I'm thinking it really benefits from a bit of cold conditioning. The harshness is gone as is most of the cattyness and its developed some nice stone fruit flavors.