most sensitive test to determine whether seeds are living or not?

Answer 1

Well, the definitive test is to plant them and see what happens.

Beans will float in water if dead, I do know that. But so do living coconuts... so it won't work on everything.

Answer 2

seeds shouldn't ever "die," because they have the feature of suspended animation, which allows them to basically sit forever until they're planted. i'd just assume that the seeds are living.