I decided to beat my egg whites for 1 hour...

...using cream of tartar, always touted as the fail-safe solution to overbeating egg whites -- when beaten to stiff peaks. As baking is part of my profession, I like to explore every claim. Exactly how "safe" are your egg whites from falling apart when using cream of tartar? I placed 1 cup of egg whites in a stand mixer and beat them for 1 hour on medium-high with 1 teaspoon of cream of tartar (1/8 teaspoon per large/30 g egg white), checking them after 15-minute intervals. What happened? After 35 minutes, the egg whites were still soft, glossy, and perfectly beaten! After 45-50 minutes, they began to pull in toward the beater and were a bit crumbly. After 1 hour, they were slightly broken and tight, but still "usable," to an extent (in a pinch). Amazing! So yes, you can accidentally forget your egg whites for at least thirty minutes (does that ever happen?) when using cream of tartar, knowing they'll be in perfect condition when you wonder back!