Königschaffhausen-Kiechlinsbergen eG Steingrüble Spätburgunder Weissherbst Trockenbeereauslese

I've had this bottle for a couple of decades, afraid to open it because it's such a bizarre wine and likely had a hard life before I took it in (outside of bottle very distressed, though fill not bad). The color was dark brown (weissherbst meaning blanc de noir, but this was far from blanc). It was most like a PX sherry in color and raisiny sweetness. Excellent acidity. The remainder (lots of the bottle as others seemed less positive …