When plums are sour?

Question

I took a bite of a plum this morning and it was really sour. Does that mean it is not ripe or too ripe?

Answer 1

If it was sour, then it wasn't ripe. when it is gooey, smushy, and to too sweet this means its too ripe. mostly it is the skin that would be ripe, though.

Answer 2

not ripe..also sometimes the skin is the only part thats sour.