Both processes work; there are consequences for either choice.
Rehydrating your yeast if you do it properly should yield a higher viable cell count. That included using clean potable water with some mineral content being better than distilled/RoMo/ultra pure water; measuring the temperature of the water and hydrating at the right temperature for the strain used (see manufacturers instructions); doing so in a manner that doesn't contaminate the yeast (working sterile is a lot harder than people like to think); attemperiating the yeast to fermenting temperature, not doing so can kill as many as pitching dry.
Sprinkling the dry yeast onto the wort also works, again at a price in killed yeast, but there is a saving in time and risk of infection. When a manufacturer provides instructions follow them, that includes pitch rate, temperature, cooling rate, aeration...
I remember a couple of years ago when the Canberra Brewers went to the Wig and Pen, many favorable comments on the beer and abject horror at seeing the brewer climb up a ladder and sprinkle a brick of yeast straight into the fermenter. It works and one of the most respected craft brewers in the country regarded it as the best choice (at that time in that brewery in that beer)
Guys it isn't an attack on our manhood when someone disagrees with us, lets not let this discussion get personal nor start a Hydration Jihad, we are talking about alternatives and their pros and cons, if other people reach a different conclusion to you... I love the old Rolling Stones line "Well he cant be a man cause he doesn't smoke the same cigarettes as me."
Lets relax and enjoy the conversation.
Mark
