I don't recall buying kimchee before, or if I did I certainly don't recall this happening: I just returned from the store with a jar of kimchee. Well sealed with the plastic rim on it, refrigerated, well before the "buy by" date. When I opened the jar, the juices immediately started bubbling up and the contents inched up out of the jar a bit. Is this common? A bit disconcerting...but I realize this is a fermented product so perhaps I shouldn't be so surprised.