Just say no to gas grilling
In the interest of full disclosure, my July 4 grilling will probably rely on gas. Using a gas grill still gets you out of the kitchen and into the backyard, and it's undoubtedly less hassle than using charcoal or wood chips.
But if you want honest-to-goodness grilled meat, you've got to stick with the classic fuel. Smelly aromatic compounds released by charcoal and wood permeate your grilling meat, and when juices from the cooking drip down onto the hot fuel, even more chemicals are unleashed upon the feast. In fact, foodies in the know say that the best way to get well-cooked, flavorful meat is to use a combination of charcoal and wood chips. The wood is more reliable when it comes to releasing the right flavor compounds, like guaiacol, which is produced when the lignan in plant cell walls breaks down in fire and is responsible for that quintessential smokey flavor.
Well done meat is literally bad for you
I'm a rare-meat evangelist, to be fair, and I'm definitely that person who balks when someone makes the mistake of ordering a "well done" burger or steak in my presence. There's no accounting for taste.
But while underdone meat runs the risk of giving you nasty bacterial illnesses, there's also evidence that charred meat might not be great for you.
When meat is cooked at extremely high temperatures (like on a grill), some chemical reactions produce Heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). PAHs are the delicious flavor notes that infuse your meat when drippings hit the fuel source and cause aromatic flames, and there's no definitive link between HCAs and PAHs and cancer. But some studies do indicate that they could put you at risk. There are no formal recommendations for how much of these compounds it's safe to consume, but the National Cancer Institute says that concerned folks should limit the time and heat of meat cooking, which cuts way back on the number of these compounds present in your food. And don't let your meat blacken or char on the outside: It's an unnecessary risk, and it's also gross.
Make your burgers healthier and tastier
All this is to say that you want your burgers to spend as little time on that deliciously high heat as possible. The solution? If you insist upon a well-done burger for matters of taste or safety, make your patties so they cook more evenly. Forming them with a dimple — or even a doughnut-like hole — in the middle exposes the meat more evenly to heat, so the center of the burger can cook well enough to kill bacteria (160 degrees Fahrenheit is the safest threshold for commercial ground beef) before the outside is a charred mess. And don't forget to flip often! If you're using meat that's been freshly ground from good cuts of meat (or better yet, that you ground up yourself!) you can feel safe and smug grilling to lower core temperatures and avoid the issue of charred edges altogether.
Some research suggests that marinating your meat — or adding tasty things like rosemary or garlic to it — can make fewer of these carcinogenics show up. It may be that adding moisture is the key, or that the antioxidants in certain foods can prevent their accumulation. But hey, even if the jury isn't out yet — nobody ever complained about marinated meat or a well-seasoned burger.
In fact, getting extra moisture into your burger is important for optimal deliciousness: When meat is ground up, muscle fibers are pulverized and start to leak moisture. To put that lost juiciness back in, you can mix in some kind of liquid when you're forming the patties — even plain old ice water will do. And while flipping frequently is a good way to avoid dangerous compounds in the meat, doing that move where you press the spatula down on the beef is a bad call. It makes a satisfying sizzle, but that's only because it's squeezing much-needed liquid out of your dinner.
Don't forget the rest of the meal
Better living through chemistry doesn't have to stop with your grilled meats. You can also use chemistry lifehacks to keep your beer from getting skunky in the summer sun and craft the best (and healthiest) guacamole of all time.
Oh, and you should grill some fruit: The high water content means that fruit — especially extra juicy stuff like watermelon — gets a super-concentrated flavor boost when it's cooked on a grill.