I ordered four extracts from NB and received four Wyeast liquid yeast smack packs. There website specifically recommended against purchasing liquid yeast from them during the summer but I did so anyways.
The yeast/package was shipped on Monday and arrived Friday night, where I immediate smacked two of the packets and put the other two in the fridgerator. The two I smacked that night inflated as normal and I made yeast starters out of them, which I just pitched yesterday.
After pitching yesterday, I took the remaining two smack packs out of the fridge (both are Wyeast 1084 Irish Ale), smacked them, went to a movie and when I came back they were not inflated. I went to bed, and 8 hours later they were still not inflated. I made yeast starters out of them this morning (and verified the inner pouch was punctured), and its been about 8 hours now and there is no activity.
Is it just a coincidence that the two smack packs I used last week right from the UPS package inflated while the two that I had stored in my refrigerator for a week did not?
Main question: Does a smack pack which does not inflate suggest that the yeast died, or rather became unusable?