Any one heard of this? Supposedly the brisket from the left side of the steer is more tender.
Most steers rest on their left side. When a steer gets up it has to use the brisket muscles on the right side more than the left to push itself up. This extra workout on the right side makes it tougher (and not as tasty) as the brisket on the left.
So how do you tell if a brisket is left-handed? Take a packer brisket and lay it fat side down with the narrow point end facing you. If the curve on the point end curves right you have a left-handed brisket.
It's not a science, it's an art. And it's flawed.