Originally Posted by cl00bie
Do you mean after the yeast starts "working" or immediately after it's added? When I added my yeast, I shook the carboy until the wort was milky all the way through.
That's fine. Lots of folks do that to oxygenate the wort and because they think the yeast need to get "mixed in" to the wort, but it's not really necessary to mix it up.
Once fermentation starts, there's no need to shake up your beer other than a gentle swirl if you're confirmed a stuck fermentation. It's passed the reproductive phase so it doesn't need O2 anymore and you'll just make it angry.
Don't make your yeast angry. You don't want to see them angry.