Ideally 15-20°C (59-68°F)
Pitch the yeast directly in the fermentation vessel on the surface of the wort at or above the fermentation temperature. Progressively sprinkle the dry yeast into the wort ensuring the yeast covers all the surface of wort available to avoid clumps. Ideally, the yeast will be added during the first part of the filling of the vessel; in which case hydration can be done at wort temperature higher than fermentation temperature, the fermenter being then filled with wort at lower temperature to bring the entire wort temperature at fermentation temperature.
With Prior Hydration
Alternatively, sprinkle the yeast in minimum 10 times its weight of sterile water or boiled and hopped wort at 25 to 29°C (77°F to 84°F). Leave to rest 15 to 30 minutes, gently stir and pitch the resultant cream into the fermentation vessel.