I bought a vile of WLP001 and when opening it was highly carbonated and under a lot of pressure. The smell was a little sour but not too bad.
I assumed it was contaminated and didn’t use it, but is it possible the yeast was ok or is that a sure sign of a bad tube of yeastes?
Would it be proper to bring it back to the brew store and ask for another bottle or is that just a risk of the hobby?
Thanks,
The vials of yeast are often a little carbonated if you let them warm up for a while before opening. But I guess it’s better safe than sorry. You could brew up a 1 gallon batch and pitch it just to see what happens. Could be good! what kind of yeast was it?
I agree, it was probably fine and just got warm at some point. A small starter like morticai suggests is a good idea.
Also it’s a good idea to let it sit for a little bit after you shake up the vial before you open it to reduce the foaming over effect.
Agree with the others, it was most likely fine. In fact, I contacted WY about this once and they said sometimes when they do a run of filling their packs they sometimes get some yeast in the packets that is still slightly active. I assume that WL experiences the same thing. And, FWIW, I have had many vials that did this. Regardless, I suggest always making a starter.
I’ve had White Labs vials arrive in the mail that had gotten so hot they leaked inside the box. With a starter they were still fine but I did learn that I can’t mail-order yeast most of the year down here.
Timely thread! Last night I was making step 1 of my starter for next weekend. When I cracked the seal on the vile of WLP800 I got a nice spray of yeast. After slowly releasing the pressure I went ahead and pitched it. All I smelled was yeasty goodness and it seems to be chugging along nicely this morning. After all, I’m a home brewer and its all part of the adventure!
The mfg date of my WLP800 was somewhere around 3-18-11. Just out of curiosity, what was the mfg date on your WLP001?
Thanks for replies, I’ll not worry about it so much next time.
Thought I put the bottle back in the fridge but can’t find it, so not sure of the date. I had a safale -05 as a backup yeast I put in the starter so it worked out ok. Always have that backup yeast 
You should actually never make a starter with dry yeast because the glycogen in the cell walls are already built up and making a starter make cause the yeast to deplete those reserves, especially considering the cell count in a pack of US-05 is over 2Xs that of a vial, maybe much more if the vial is old. Just sprinkle on top of work or, for best bet, rehydrate in 90 degree warm water.
Also, I always sanitize the vial and/or smack pack before opening so that if any sprays on the outside and drips into my starter wort it won’t carry a contamination in with it.