Extract Root Beer - didn't ferment?

I've started making root beer for the first time (though I'm an experienced beer homebrewer).. followed some instructions online basically that says boil + mix in 4# sugar to 5gal water (bottled purified, not distilled) + extract (Zatarains) wait to reach pitching temp., throw in the yeast (I used Safale-S04) then let it sit in a fermenting bucket for about 12 hours. The idea behind this to get the bulk of the fermenting out of the way, then bottle it so it will still produce carbonation - just not explode the bottles. Anyways, I did this last night and now about 11 hours later I can't tell if it's done anything.. Looks the same, no bubbles, no foam.. Any ideas?

24 hours.. still no activity.. wondering if I should use a yeast smack pack? Though I don't want yeast-y flavored root beer either.

What ended up happening with the root beer? Did you bottle it?

Yes I added some yeast nutrient and bottled it.. its carbonating now, but tastes like butt.. I think it was just the extract though - not very good stuff IMHO - I'm going to try another brand.