I'm relatively new to homebrewing. Last night (roughly 24 hrs ago) I started two different brews.. Both a fairly similar but only one of them has started to ferment with it's air lock bubbling away and the crust inside the barrel has started to form, while there has been no movement in the other.. Should I be worried? How long does the fermenting process take to start? When should I think about adding more yeast? Thanks, Brad.