I’m afraid I’ll kill the yeast—can this happen?

Yeast that needs proofing (soaking in warm water), such as active dry or cake yeast, will die if the water is hotter than 120°F. (or if the water is ice cold). Instant yeast, also called Rapid Rise, QuickRise, Instant Active Dry, Perfect Rise, or Bread Machine Yeast, can be mixed right in with the flour without soaking it in water first. Store it in the freezer and it will stay alive for at least year.