Infection or normal

Hello:

I brewed a batch of pumpkin ale on Saturday and pitched a pack of Wyeast 1469. For the last few days there has been no activity, I was going to take a reading tomorrow and maybe pitch again (the pack was an older pack.) Today while I'm at work my roommate texted me saying the beer was foaming out of the airlock, and sure enough it is (part of it I think there was only 1 inch headspace in the bucket.) But with this much lag time how do I know if this is normal or an infection?

Infections are slow.

What you have is either huge lag time, or change in environment (temperature most likely)

Pretty normal. Usually takes a few days before it gets good and foamy, especially with some lag. With only 1" headspace, doesn't surprise me at all, just about every yeast will exceed that.

If you do that again, just stick a blow off tube in from day one.

Way to early to suspect infection. Don't open it to check, just let it ride another week or two. Highly doubt infection.