Subdivision surface modifier is acting differently than from this tutorial?

This is the tutorial I’m following(starts at the exact time where I’m having issues): https://www.youtube.com/watch?v=Xbc3KMIOuKM&t=4m26s

I’m having trouble getting this result with the subdivision surface modifier:

For some reason, I get this:


What am I doing wrong?
Also, here is my blend file: https://www.dropbox.com/s/pzvekb4mjl8fmqj/BEER.blend?dl=0

Delete the top and bottom faces


Thank you!!