I wanted to try a Wyeast and got this mid december - but it was in the fridge about a month before I took it out and smacked it on saturday. Made up a starter with spraymalt and sat back to watch it go - but it didn't
Now (two days later) it's bubbling away happily, but there's not a sign of any sort of head forming

.... is this usual? or something wriong with it? And how will I tell ... ?
T