Wyeast question

[Kevcor]

Brewing an American ale today. While I was making the yeast starter yesterday, using a Wyeast package, I thought if I am making a starter using a stir plate do I need to smack the packet inside and wait the time for the bag to expand or can I just let it get to temp and pitch. Any comments?

[Rusty Nails]

Wyeast covers this on their website, along with a lot of other questions. They also have pitch rate data. I strongly reccommend anyone using Wyeast to check out their website and FAQ's.
They even have a video showing how to break that little packet without chasing it around the counter top.
Ed

[MaltLicker]

I always break it.  The nutrient pack is one reason I prefer Wyeast; it is "free" and gives an indication to the yeast vitality of that package. 

If it is slow to expand, I figure the cell count is lower, so I either make the starter a little bigger, or double-down before brewing.