Does dried seaweed (dashi kombi) expire?

Question:

its been in an airtight bag for about a year. Is it still good?

Answer:

It's perfectly fine...kombu does not expire despite some of the misinformed answers. Kombu isn't eaten (normally) but it's used for making dashi (stocks using various ingredients, bonito flakes, shittakes or sardines).

Kombu is just steeping in the simmering water to add that "umami" flavor. After being steeped for 15+min I just throw mine away (and so do almost every other Japanese person I know). You can always save it to make a nidashi which literally means "2nd dashi".