I’ve noticed it. The carbonation seems to amplify both the bitter flavor and aroma. Perhaps it’s a dual action via tastebuds and the aroma being expelled by the out-gassing of the beer.
I’ve noticed lately that if there is too much suspended yeast in a hoppy beer it tastes much more bitter than after the yeast settles out. could that have anything to do with it?
I’ve never noticed yeast being bitter by themselves, but I’d aay that in bitter beers the yeast are absorbing some iso-aa or they are sticking to the outside of the yeast cells
^ This. That’s one of the reasons it’s advantageous to cold crash prior to dry hopping (so I’ve heard), then bring temp back up. I notice similar effects in my beer especially when the sting of the CO2 hits your tongue.
Carbonation will amplify the components and change the perception in any case. Try this with a commercial mead (carbonate half the bottle, compare it to the other still half) or cider (open one bottle and let it go flat, compare it to an unopened bottle) as well.
I make a jalapeno ale every year for two local beer festivals (http://bbbrew.com/index.php?page=brewBlogDetail&filter=buergermeister&id=55). When I taste the uncarbonated beer in the hydrometer the pepper and heat are more dominant. If I carbonate it to 2.5 vols then I get more of the smoked malts and even some cascade flavor. Pepper and heat is still there but much more subtle.
Temperature also plays a role. Try this with your wife. Put the same bitter in two soda bottles and carbonate them. Put one soda bottle in the fridge, leave the other one at room temp. Once the one bottle has cooled pour them into two glasses and see what she says. Then tell her it’s the same beer, just at different temps.