Originally Posted by johnp
Lol I asked two questions in your quote. Is it ok? Or does it defeat the purpose?
Ok, just playin'
As bleme mentioned, the cell walls of dried yeast can allow sugars to penetrate to the point that the yeast can literally explode. By gently hydrating the yeast the cell walls return to their desired condition where the yeast control the admission of wort.
Bottom line, if you're not going to hydrate with sterilized water, you'd be better off just sprinkling the dry yeast on top of your vessel of wort and let it sit there for 10 minutes before stirring...