Ahaha, risky game!
I was told it had a slight aftertaste of wasabi, a green spicy substance derived from a sort of horseradish. I, having almost no sense of smell, didn't feel or taste any spiciness.
If you didn't feel anything then either you have a genetic defect or there was no wasabi in it (or only homeopathic doses). Which would be no surprise because the stuff is quite expensive.
The wasabi paste you get in my Germany has only one percent wasabi in or so in it - and 30% other horseradish.
THe plum was probably indeed pickled plum. Umeboshi Extremely sour.
If you feel really brave, you could try tasting natto. It is not a sweet though. But easy to remember and recognize, in severa ways...
Well, there is a good chance there was very little something in it. The others described a bit of a sharp aftertaste, almost like an afterthought to the sweetness. And they all felt it at the same time. Except me.
Thanks for your replay. I'll be sure to try interesting German delicacies if I ever find my way over :)
You could start with bread.
If that gets boring after a year or two we will find something else :D