Cooking meat and poultry perfectly is tricky business. And once you’ve erred, you’re stuck—not much can fix a tough burger or dry chicken breast. The secret is to prevent mistakes in the first place all along the way, from the market to the carving platter, and a little science savvy can help. Below are five common blunders, plus my tips for avoiding them.

1. Making burgers with ground sirloin

Making burgers with ground sirloin might seem like a good idea. After all, sirloin steak is famously tender. And ground sirloin’s high price suggests that it’s somehow superior to cheaper ground chuck. But when it comes to burgers, ground chuck is better. A hamburger’s flavor depends on two things: the flavor of the ground meat and the amount of fat in it. In both flavor and fat content, ground sirloin is lacking compared to ground chuck. Sirloin comes from a little-used muscle, so it’s very tender but not very beefy tasting. Chuck, on the other hand, comes from the cow’s heavily used shoulder muscles and has lots of flavor. And ground chuck has adequate fat, which melts during cooking for a burger that’s succulent and delicious, even when cooked to medium well. Lean ground sirloin doesn’t have enough fat to keep a burger juicy when cooked through.

2.Carving ham into thick slices

Carving ham into thick slices is a common enough practice—so how is it a blunder? Because ham tastes even better when sliced thin. A thick ham slice has much less exposed surface for a given weight than the same amount of thinly sliced ham. The extra surface allows the taste receptors in your mouth to contact more of the ham’s flavor components. There are also more surfaces exposed to air, which may help disperse the ham’s aroma, and what you smell has a lot to do with what you taste.

3. Overcooking meat in stir-fries and sautés

Overcooking meat in stir-fries and sautés is easy to do. Meat stores heat energy and after it’s removed from the heat source, it continues to conduct heat from the exterior toward the center. This carryover cooking can raise the meat’s temperature by 5° to 10°F depending on its size and density. The larger and denser the meat, the longer the cooking continues, and the higher the temperature can go. In stir-fries, the pieces of meat are small and the cooking time is brief, so it’s easy to miss the window for perfect doneness. To avoid overcooking, pay close attention and remove the meat from the pan before it’s as done as you want it: I take chicken out of the pan when it’s still slightly pink in the center, beef when it’s still a little red, and pork when it’s just barely pink.

4. Frying bacon over high heat

Frying bacon over high heat causes grease to splatter all over your stovetop, and the heat can lead to the formation of dangerous compounds. Most bacon is cured with a liquid brine that contains a very small amount of sodium nitrite (less than 40 parts per million). This preservative contributes to bacon’s color and flavor and inhibits the growth of Clostridium botulinum, the bacterium that causes botulism. Since the late 1950s, numerous researchers have shown that nitrites can react with amino acids (the building blocks of proteins) to form nitrosamines, a known carcinogen in animals. This nitrite-to-nitrosamine reaction can be exacerbated by high heat—an excellent reason to cook bacon at moderate temperatures. Besides, lowering the cooking temperature drives moisture—which explodes in hot grease—more slowly from the bacon. Start the bacon in a cold pan set over medium low, and you’ll get a nice steady sizzle in the pan instead of splatter on your stove.

5. Cutting raw chicken breast with the grain

Cutting raw chicken breast with the grain before stir-frying or sautéing results in tough, wrinkled wads of cooked meat instead of nice flat pieces. In poultry, bundles of muscle fibers run the length of the breast. During cooking, muscle fibers shrink lengthwise. If you slice the raw meat with the grain (parallel to the fibers), the fibers will contract along their entire length as they cook, shriveling the meat into tough chunks. Preventing this is easy: simply slice the raw chicken (or pork or beef) across the grain as shown at left so the muscle fibers in each piece are short —just the thickness of the slice. While the slices might shrink slightly in thickness as they cook, the meat will remain nice and flat, and your stir-fry will be masterful—if you don’t overcook it (see #3 above).