"You have to keep beating it for longer," my grandmother instructed me. "It isn't pale yet. It's still too yellow." Subscribe to our newsletter for the latest sci-tech news updates. I didn't ask how ...

“You have to keep beating it for longer,” my grandmother instructed me. “It isn’t pale yet. It’s still too yellow.” I didn’t ask how long this would take. I was nine years old, and I understood what ...