yeast not active?

I received a kit from austin homebrew supply with a kolsch wyeast activator pack. I smacked it yesterday morning around 9:30 am and by 3 it looked like it only swelled a little if at all. I figured since when I shook it and I heard it fizz the yeast was active. I pitched it yesterday at around 5:00pm (wort was chilled with an immersion chiller tp 75 degrees) and I have not seen any fermenting activity yet. When I did a kolsch with a wyeast activator pack before it was a pretty violent fermentation. if for some reason the yeast isnt active, can I run to the lhbs tomorrow and buy some other kind of yeast to save the beer?

The smackpack swelled, the yeast is working. Some batches take a long time to get activity, some take off right away. I've had full fermenation done in 48 hours, and I've also had NO activity happen in 72 hours. Cooler temps can also give more lag time on activity.

Ok thanks Ill check again. If its not active by the tonight, should I or can I pitch in more yeast? it does look like there is a thick yeast cake at the bottom on the carboy like normal, but I suppose this could just be what settled in the beer so far.

Yes, if you don't see ANY activity by tonight, go pick up some yeast. You've made a kolsch before, so also look for the krausen walls on the sides and top of the carboy. Actually, most LHBS's are closed on Sundays, get some tonight if they're closed tomorrow. Also swirl that carboy around like you're trying to get it dizzy enough to puke, and that should help get it going as well.

If nothing else, a dry yeast will be an OK substitute. Not ideal for kolsch, since it is its own style, but better than nothing! It'll still be beer.

lack of a starter, I don't see a mention of direct oxygenation, and possibly slightly lazy yeast...give it a full 72 hours from pitching before you do anything. watch for starts of fermentation (tiny bubbles up the sides, even if the airlock isn't gurgling)

After 72 hours, I noticed a small amount of activity and when I checked this morning it is fermenting away! Thats the laziest yeast I have ever had

The Koelsch yeast I got from AHS last week was similarly slow - the smack pack didn't really swell, and the 1-L starter I did took 5 days to ferment out. Once I pitched it, it took another 36 hours for the primary to start showing visible signs of fermentation. I even fed it olive oil! It looks very healthy now, however.