Namashoyu question

[JCB44]

I bought my first bottle of namashoyu and wanted to just taste it(even though I am in the middle of a mc). When I opened the bottle the stuff sprayed out like champagne and I lost half of it. Is this normal or is this bottle bad. I did not shake it up, but it was warm. I hope that is good because it was a little pricey.

[Revvell]

I've never had an issue with it spraying but usually that means it's bad. Hard to tell w/out smelling/tasting it. If you got it locally, return to the store and get a new one. I don't think they go bad since it's a fermented product but, just to cover your tail.. I'd return it and tell them why.