Well, the stout still has the taste despite being brewed two months ago, though it is now drinkable. The AIPA is still bulk conditioning.
Yesterday I bottled a Hefeweizen, and there it is again. Not nearly as pronounced, and I can tell that behind that taste is the makings of a great hefeweizen, but it is there for sure. It wasn't apparent in the trial jar, only after fermenting. The only thing is common between the three beers was the fv and peco boiler. Again, there was scorching on the element, but not as much - perhaps because of the lower grain bill and the fact that I skimmed the foam off during the boil, though the 50% wheat bill would probably encourage scorching if anything. Burnt residue still needed to be scraped off the element. The fv received a thorough clean - warm soap wipe-down, much rinsing, 24h with warm oxy, rinsed again, vpw, rinsed again, boiling water, then star san. This thing was as white and odourless as the day it was bought. There are no visible scratches, so I'm fairly certain it isn't the fv. By elimination, it will probably be due to scorched wort, either hidden by the sweetness of the trial jar or exacerbated by an interaction with the yeast.
So, today is a diagnostic brew day. I'm doing a Best Bitter, maxi-biab like MyQul does, so that I avoid using the peco for the boil and instead use my casserole and 15L stock pot to do a concentrated boil, then water down a bit in the fv. This way, if it is still there after bottling then I can blame the fv. If it isn't, then the element was the culprit.