Add the yeast culture and incubate until high kerausen is observed. It will be ready to pitch at that point. Just a note, a brewer found a package of 1098 that was 8 years old. He activate it and it swelled within three days and made a great batch of beer. That is the oldest yeast we know about that survived and did not need any special resuitation.
Nutrients are generally beneficial when propagating yeast.
Q. Why does dry yeast rouse so much quicker than liquid yeast. When dry yeast is hydrated, it foams up on the surface of the fermenter almost immediately. This is due to the hydration process, and is not indicative of fermentation actually beginning, it just appears to. According to the manufacturers of that product, the lag time for dry yeast is about 12 hours. At Wyeast we have been brewing for more than 20 years.