Hello -
I am new, so I hope this fits in the general discussion. I recently made a west coast IPA and kegged it in a 5 gal corny. I am getting a very strong plastic off-flavor. I used spring water and conducted a secondary fermentation (I have read not to do this step again). My question is…can I still remove the plastic off-flavor in the keg and salvage the beer or does it need to be dumbed? Thanks.
The plastic flavor is a phenol. That’s a fermentation issue (not specifically related to doing a secondary - I personally think using a secondary gets a bad wrap, I’ve judged far too many beers that have off flavors from sitting too long on hops or yeast in a primary fermenter, but that’s not your issue). Unfortunately, you will not be able to get rid of it once it’s there. It could be caused by poor yeast health or by a contamination with wild yeast or bacteria.
Welcome back! Can you quantify how long is too long, or is it one of those “it depends” things?
Unfortunately, it is a depends thing with how long to let beer sit on yeast. It really depends on yeast health and probably the shape of the fermenter. With a flat bottom fermenter, you’ll have more direct exposure to the beer with the trub at the bottom. I’ve had beers sit on yeast for a few weeks post crash without developing off flavors, but I wouldn’t want to make that a regular practice.
For dry hopped beers, you’ve likely got everything you want out of the hops after five days to a week and will start to get things you don’t want from the plant matter if you let it sit much longer.
A lot of the recent research on dry hopping I’ve seen says 48-72 hours is plenty and longer can be counterproductive. I’ve started doing it that way and have been very pleased.
Could it be a ferment temperature issue?
Any chance it’s the beer line? I used to always be able to taste plastic with pvc beer line, especially after the beer would sit in the line for awhile.
Awesome info. I really appreciate it.
I was thinking the same thing, but this taste is a bit overwhelming and you could smell it in the glass. I was told to replace it with a different type of beer line for both CO2 and beer pour.
There’s unfortunately no way to save it at this point. I agree with Gary that is is a phenol. And there are a few pathways. The two most common are: chlorine/chloramines in the water (and that includes the possibility that chlorine bleach was used a disinfectant) or yeast derived; either from a yeast that creates phenolic flavors (like a Belgian or German Wheat) or a wild yeast infection.
Since you used spring water, and assuming you didn’t use bleach, that would leave a yeast problem. I’m guessing a wild yeast infection.
Secondary vessels are fine as long a you have a way to purge them with Co2. Otherwise I do believe they should be avoided. But I also agree that the beer can’t sit on yeast or hops too long. Regardless, unless you picked up an infection in your secondary, that would not be the problem.