This colorful and popular expression is a misnomer. Blood contributes little to the redness of a steak because most of it is bled out of the meat at the slaughterhouse or butcher shop. The confusion is easy to understand because myoglobin (the principal pigment in raw meat) shares certain characteristics, including color, with hemoglobin (the red pigment in blood). However, myoglobin is distinct from blood: It is found in muscles, not arteries.
