Here’s a great video from the folks at Cook’s Illustrated magazine that describes their lab testing of cooked flank steak and strip steak and the relative force needed to cut both meats with the grain and across the grain.
Tests using a texture analyzer showed that cooked flank steak took 4 times the force to cut with the grain than across the grain. For cooked strip steak, it took almost 2 times the force to cut with the grain than across the grain. Most interestingly, it turns out that the force needed to cut both cooked flank steak and cooked strip steak across the grain is almost the same!
The Bottom Line: How steaks are cooked, to what internal temperature, and how they’re sliced after cooking have a huge impact on tenderness; and cheap(er) cuts like flank steak, skirt steak, and hanger steak can be almost as tender as expensive steaks when cooked and sliced properly.
Hope you enjoy the video!