I picked up a package of Omega Labs Irish Ale liquid yeast last Saturday. I placed it in my fridge when I got home and took it out the following morning (Sunday) before I expected to brew. It sat out for about 3-4 hours before I realized I wouldn't be able to brew that day. I placed it back in the fridge.
I plan on brewing the following weekend. Will my yeast be alright, or should I pick up a "fresh" package?
It was packaged in early July; it is currently 3 weeks into the following August.
Your yeast should be fine. Room temperature does not hurt yeast, it just "accelerates" it, meaning it eats up nutrients faster. I do not have any experience with Omega Labs yeast, but the fresh yeast I use has a best-before date set to four months after the packaging date.
The same principle applies when making lagers vs. making ales. Ales often reach final gravity after 3-4 days while lagers can take as much as two weeks. Lagers take more time to ferment because of the lower temperature which causes the yeast metabolism to slow down.
If you're still uneasy you could make a small yeast starter using some dried malt extract or even table sugar. A yeast starter would wake up the yeast and make it reproduce, resulting in a higher viable yeast cell count. A lot of people would disagree with me on using table sugar, but I firmly believe that a yeast starter made with sugar is better than no yeast starter at all. I have tried it on a few occasions and I have seen nothing that woud make me believe otherwise.
3-4 hours shouldn't hurt it much it might take longer to get going once you pitch it but sence the packet is still so new it should be fine.
