Identifying the ‘grain’ of meat
Often, a recipe states to slice with or against the grain of the meat.
Is there a standard way to tell?
Are you familiar with the grain of wood? It's the same idea. Muscle tissue is made up of fibers that run roughly parallel to each other. Look for faint parallel lines running down your cut of meat...that is the grain. It's particularly easy to see on cuts like flank or hanger steak...not so easy on fillet. See the picture...the black arrow is running with the grain.