People say there is no reason to rehydrate, if this is true why does the Safale website have these instructions?
Sprinkle the yeast in minimum 10 times its weight of sterile water or wort at 27°C ± 3°C (80°F ± 6°F). Leave to rest 15 to 30 minutes.
Gently stir for 30 minutes, and pitch the resultant cream into the fermentation vessel.
Alternatively, pitch the yeast directly in the fermentation vessel providing the temperature of the wort is above 20°C (68°F). Progressively sprinkle
the dry yeast into the wort ensuring the yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes, then mix the
wort using aeration or by wort addition.)
I rehydrate per the instructions and have never had a problem and I dont have to spend the extra for more packs, (32 gallon ferment at a time), I rehydrate (7) packs instead of pitching 11-12 packs dry.