Yes, both dead yeast and water that is too hot can prevent naan dough from rising properly. Yeast needs to be alive and activated by warm (not hot) water to leaven the dough.
Yeast is a living organism that produces carbon dioxide, which causes dough to rise. If the yeast is dead, it won't produce gas, and the dough won't rise. Yeast can die if it's old, improperly stored, or exposed to extreme temperatures.
Water temperature is crucial for activating yeast. Warm water (around 105°F to 115°F or 40°C to 46°C) provides the ideal environment for yeast to thrive. If the water is too cold, the yeast will be sluggish and may not activate properly. If the water is too hot (above 130°F or 54°C), it can kill the yeast.
To test your yeast, you can perform a simple proofing test. Mix the yeast with a small amount of warm water and sugar. If the mixture becomes foamy within 5-10 minutes, the yeast is active. If it doesn't foam, the yeast is likely dead and should be replaced.
Always check the expiration date on your yeast package. Even if the yeast is within its expiration date, store it in an airtight container in the refrigerator or freezer to prolong its shelf life.