It has been over 20 years since I last used a pack of liquid yeast. For my next beer I plan on using 1450, but I'm slightly concerned because it wasn't delivered in a timely fashion. I ordered the ice pack, but FedEx took their grand ol time. Not the end of the world (I'll have a pack of US-05 on hand just in case), but is there a way of knowing pre-pitch if the liquid yeast is viable?
The directions say to break the interior nutrient packet, vigorously shake, and (optional) let the yeast sit for 3 hours (give or take) at room temp. If I do this, the package should expand.
This is probably a ridiculous question but can I assume that if the package blows up, the yeast is happy? And if it doesn't, go to Plan B? Or is an expanding package irrelevant to yeast health?