Hi there, Madeline! You're right, water that is about 115°F or hotter can start to kill off yeast cells. When you make your tangzhong roux, you'll want to make sure you let it cool to lukewarm before mixing up your dough. We hope you enjoy this technique and happy baking! Morgan@KAF
May 3, 2019 at 10:45am
In reply to I was always told that hot water kills the Yeast?? But I will… by Madeline gallo (not verified)