I brought it to work Wednesday and it looked like a normal banana, yellow with brown spots, just right for a snack.
Well, I didn’t need a snack then, so I left it in my drawer until today, when I needed breakfast.
By then it had overripened to a uniform grey, and black around the stem. Not abnormal, but not entirely appealing either. I figured it must have been because it got too cold or something, so I ate it anyway.
It was horrible… completely unappealing. Not sweet at all and even kinda mediciny tasting. I had to force myself to finish it, mostly so I don’t keel over from low blood sugar before lunch. That was about a half hour ago.
Sounds like a classic case of UPD, Under Peel Discoloration. Cavendish Bananas (the one 99.9% of Americans eat) have a very tight temperature range they like, fall below about 53 or 52 degF and you get what you got. The black stem may have been the additional bonus feature of Crown Rot, or maybe just the damage caused by a broken neck.
I’ve got a couple I’m trying to make go black for banana bread purposes, and the damned things insist on staying mostly yellow and cheerful! I guess I should try the paper-bag-with-apple thing, but there are any other ways to force bananas to go overripe? (That’s how you get serious banana flavor in your banana bread.)
The softness is usually due to oversweetness, the conversion of all the starch into sugar.
It may taste strange, but it’s not harmful.
In fact, I usually use the grey ones in something that needs to be sweet, like pudding and pie filling.