Grind your own ground beef
If you really want to know what's in your hamburger,
grind your own. This way you can control the fat
content as well as the primal cut. If you have the
energy and time, an old-fashioned clamp-on
galvanized meat grinder still works just fine. If you
have a standard food processor, you can whip up
fresh ground beef in no time flat.
When using a food processor, cut chunks of beef and
fat into one-inch uniform cubes and chill. Place meat
cubes in the processor with metal blade, taking care
to process in small (no more than 1/2-pound
depending on the size of your processor) batches.
Pulse in short 1- to 2-second bursts until the desired
consistency is achieved, usually 10 to 15 pulses. It's
important to pulse rather than letting it run. Pulsing
tends to distribute the pieces for more even chopping
and avoids excess heat from friction that could turn
your ground beef into mush. If you are adding herbs or
spices for a recipe, might as well toss them right in
before beginning to chop.

The amount of fat you add is up to you, but for best
results, use at least ten percent fat to meat ratio. Just
remember that the fat is where the flavor is, and it
also adds moisture for a juicier end result. For
burgers, a coarse grind is preferred. For meatloaf and
meatballs, a finer grind helps the meat compact,
blend with other ingredients, and hold its shape.
Always be sure to follow safe handling procedures.