[homoeccentricus]

I tasted a (commercial) beer yesterday that had a strong plastic flavor. Any idea what that could be? It was barrel-aged, could that have anything to do with it?

[speed]

Plastic is phenolic, usually yeast infection or some yeast at high temps will give this. What beer was it?

[homoeccentricus]

Plastic is phenolic, usually yeast infection or some yeast at high temps will give this. What beer was it?

Nothing one can find in the US. It was an Italian beer at a tasting in Belgium. Could that be a yeast that develops during barrel-aging, or is there no relationship?

[HoosierBrew]

FWIW, I've had a lot of barrel aged beers and never had a phenolic/plastic-y one. So I don't think it's an inherent issue to barrel aging.  I agree that it's likely an infection or fermentation temp related issue. But a barrel related infection in this case is not impossible, by any means.

[morticaixavier]

it can also come from chlorine in the water or incomplete rinsing of chlorinated sanitizers

[majorvices]

Phenols are attributed to many things, as everyone else has pointed out. It could be the barrels were left for a long time empty and a wild yeast took hold during that time, but phenols are not indicative of barrel aging.

Basically phenols are driven from a wild yeast (except in the case of hefeweizen strains and some Belgian strains - though it is important to point out that these strains produce more "clove-like" character and are much more pleasing than the plastic-clove-like character driven by much of the wild yeast) or chlorine/chloramines that are present in the municipal water (or chlorine based sanitizers).

[epic1856]

It can also be the beer lines since you mentioned commercial. There are some bars that don't clean them as often as they should.