Add yeast to warm water
Dissolve active dry yeast in a small amount of warm liquid (105 to 115 degrees F). Fresh yeast cake should be crumbled into lukewarm liquid. If the water is too hot, it will kill the yeast. If it is too cold, the yeast will not be efficiently activated. Some recipes call for adding sugar or honey to help feed the yeast.
Check for activity
Let the mixture stand for 5 to 10 minutes until bubbling and foamy. If the yeast does not bubble, start over with fresh yeast.