Help identifying off flavour

[NegimaTorikawa]

A recent batch I've transferred to a couple of 10L kegs has an off taste... but only in one of the kegs. The best way I can describe the taste is pretty close to ice from the back of a frost free freezer... It's also dropped off a lot of the hop flavors compared to the other keg. Pretty confident its either from too much splashing when transferring or maybe its new keg taste and I didn't clean it out properly.

Any case, anyone else familiar with the taste of ice from a frost free freezer?

 

[Lionman]

If you have a frost free freezer, there shouldn't be ice at the back of it?

If two kegs where filled from teh same fermenter and one tastes different or 'off' then my bet would be either oxydisation from the transfer or some type of contaminent as you have described.

I strongly suggest properly purging your kegs with CO2 and then transfering the beer in via the liquid post. Even if you do this via gravity it will be much better then filling it with the lid off.

To purge a keg fill it with no rinse sanitiser solution then use CO2 to push the sanitiser out (into a nother keg is ideal so you can reuse the sanitiser).

 

[NegimaTorikawa]

If you have a frost free freezer, there shouldn't be ice at the back of it?

If two kegs where filled from teh same fermenter and one tastes different or 'off' then my bet would be either oxydisation from the transfer or some type of contaminent as you have described.

I strongly suggest properly purging your kegs with CO2 and then transfering the beer in via the liquid post. Even if you do this via gravity it will be much better then filling it with the lid off.

To purge a keg fill it with no rinse sanitiser solution then use CO2 to push the sanitiser out (into a nother keg is ideal so you can reuse the sanitiser).

I meant non frost free haha oops.

I’ll be equipped to do a closed transfer for the next batch. Thanks for the advice.

 

[Lionman]

I'm trying to understand what that flavour would be. Bad flavour in old stale ice is usually caused by the absorption of odours from food in the fridge and freezer.

Flavours in food are made of similar chemicals to flavours in beer (not surprising given beer is a food really) which include things like esters and phenols. If these types of chemicals are making their way into the ice in a freezer and oxidising on the way then that could explain the similarity in flavour and support the theory that your issue is oxidation.

Stale beer would have similarities in flavour to stale foods and ice that has absorbed the odours of stale foods.

 

[Nizmoose]

Sounds like your off-flavour could be pretty closely related to a wet cardboard smell and oxidation is probably your best bet especially considering it's only one keg

 

[labels]

I definitely suggest oxidation is your problem. You need to identify where in your process that the problem is occurring.

 

[NegimaTorikawa]

Yep since determined it was definitely oxidation as the beer darkened up significantly.

I suspect its because I didn't purge the keg properly and it splashed in around the bottom - I've only been using a little 5L iKegger keg and have always filled it with silicon tubing and a bottling wand and had no issues... The 10L Corny was a new addition and next time I'll be able to purge it with CO2 and transfer through the ball lock. I guess the good news is I still have 10L in bottles that will be ready to go in a few weeks.

Cheers