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?

[Crusader-Rob]

The saying goes - "Don't fear the foam"

Starsan is the perfect sanitiser, and is mostly flavorless (Unless you decide to drink it straight)

[Cain Harland]

I just made a little glass of weak iodophor water to taste and while it was certainly not present it was not as bad as I might expect either and not at all harsh, tasted kind of dirty like the bad water in some cities and dried out my mouth like tannin. I'm pretty sure the iodophor in that glass was more concentrated than it could possibly be in the beer and feel pretty confident saying that unless its reacted with something thats not the off taste I'm getting.

[Peter Smith]

Next batch bottle a couple, wait 3 weeks, compare taste between bottled and kegged

[Kevin Sharp]

Maybe you could try the same concentration of iodophor in a small amount of well carbonated beer. I would imagine that would taste worse.

A couple of other thoughts:

With your kegging system do you clean the lines and taps at the same time and in the same way as you clean the keg?

Do you have the serving line hooked up while you're carbonating the keg?

[Cain Harland]

With your kegging system do you clean the lines and taps at the same time and in the same way as you clean the keg?

Yes I make about 3 L iodophore sanitizer make sure the keg has a bit of time on each end and shake a few times while organizing other stuff then hook up gas and beer line and push sanitizer out till its just foam. Usually I turn off gas after getting a bit of pressure in the keg so I'm not wasting too much CO2.

I also have beer line cleaner (same brand as star san I think) and a pump I made from weed sprayer with a ball lock post on it. If I think the lines are a bit dirty and I'm not planning on filling a keg for a little while I make up about 4L of that. I put 1/3 through each line/tap (because I have 3 taps) throwing away the first cup or so that has beer in it, then refill the bottle with what I've collected and pump through again. I figure doing it twice is better than doing more once as it leaves a little time for each one to soak before I get back to it. Then rinse the bottle and fill with clean water and push 1/3 of that through each tap to rinse out the cleaner.

Do you have the serving line hooked up while you're carbonating the keg?

Sometimes. Usually not.

[Peter Smith]

The off flavour , is it after the initial thats ok taste up front , but where bitterness should linger and tail off nicely, is it more of a cardboard/dankess,   but after two weeks that fades?

Maybe we need to come round and have a pint

[Cain Harland]

Fade yes

cardboard/dankess yes

but harsh up front as well

[Cain Harland]

More concerned about the harshness really

[Kevin Sharp]

OK, so cardboard suggests oxidation.

When you flush the keg with Co2 do you flush it through the dip tube or through the gas in port?

[Cain Harland]

gas port

[Peter Smith]

does all the off flavour fade away with time?

[Cain Harland]

It did with the last one. It was great in the end.