help!! Batch not fermenting

This batch I have is a Dunkleweisen kit I got from Norther Brewer. I pitched the yeast almost 72 hours ago and it hasn't started to ferment yet. It was a Wyeast Activator. The funny thing is that when I took the yeast pack out of the fridge and popped it, it only inflated maybe a third of the way. Didn't really inflate like it usually does.

Should I be worried? Give it more time? Is there anything I could put in it to start the fermentation process? Am I screwed?

Recipe? Temps when u pitched? Temps now?

Yeast strain?

Jay

Well, just pitching the liquid yeast in can take a long time to get going. I know it's hard, but try to be patient a little longer. It can easily take 72 hours to get going, so you're still in there! (Next time use a starter).

Is it in a carboy or bucket? If it's in a bucket, you may have some fermentation starting but just can't see it. If you look, you may seem some krausen starting to form.

Keep it warm (not TOO warm- just in the range of the yeast), and gently swirl the fermenter to keep the yeast in suspension.

Let us know if you still don't have any signs of fermentation today.

Thanks for the replies. The beer is at about 68-70 degrees. In the meantime I called the local brewshop (HomeBrew USA in Norfolk, VA). They advised me to move the beer to a warmer room, wrap it in a blanket, and give it another day.

I will try to swirl the fermenter.

Thanks guys.

Sounds like you got some low-viability yeast. They'll take longer to multiply. Any indication of a krausen?

for future reference if the pack barely swells, make a starter and postpone brewday.