Preground meat, even some ground from the better cuts of meat, such as ground chuck, may have been ground miles away and days ago. Once meat is ground, it begins to oxidize and its fat can start to get rancid. Shop at a store with a butcher in the back room who can grind meat to order for you.
Never, ever buy something labeled “hamburger” or “ground beef” for burgers. Save these for chili or sloppy Joes. Butchers toss trimmings from any cut in there, and much of the stuff in preformed patties comes from old bulls and no-longer-productive dairy cows. Those patties may also have added seasonings. You want to add your own.
You want at least 20 percent fat, not 15 percent. Many top chefs now recommend 25 to 30 percent fat, especially if you cook the meat to the USDA-recommended safe temperature of 160°F.
The easiest thing to do is pick a nice-looking USDA Choice–grade chuck steak, ask the butcher to grind it, and add more white fat if needed to get the blend up to 20 to 30 percent. Don’t waste money on expensive cuts like ribeye or Wagyu beef. The grinding process will make tough cuts tender. Go for less expensive meat that has great beefy flavor, like chuck, short ribs, flank, skirt, sirloin, hanger, brisket, or a blend.
Ask for a coarse grind, using the ¼-inch holes, only once through the grinder, and ask for it to be packaged loosely. It should come out looking like thick, wavy spaghetti. Coarser grinds and looser packing make for an uneven surface plus air pockets inside, and that’s good for holding juices.
If you can’t get your meat ground to order, buy preground chuck, which is usually 15 to 20 percent fat. (Ground round is usually 10 to 15 percent fat; ground sirloin is only 5 to 10 percent.)
While you’re at it, ask for some suet (beef fat) to freeze and mix in the next time your meat is too lean—get fresh white fat, not yellow fat. Your butcher may even grind it for you. If not, you can grind it easily in a food processor.
If you have a meat grinder, the best way to control quality is to grind the meat yourself. That way you can select the exact cut, control the fat-to-lean ratio, get the freshest meat, and reduce oxidation and the risk of microbial contamination. To further reduce risk, especially if you insist on cooking your burgers to less than 160°F, take the whole muscle steak before grinding and dip it in boiling water for 30 seconds. That will pasteurize the surface, which is where any contamination is most likely to be found. It will still grind and cook perfectly.