Chemists Host the Perfect Barbecue
Their cooking formula? Avoid well-done foods and match your beverages to your sauce.
Aug 21, 2009
Originally published: Aug 20, 2009
By Devin Powell
Inside Science News Service
 "Photo: Linda Wang/C&EN/ACS, License: N/A")
WASHINGTON -- By the end of the summer, backyard grill masters across the United States will have barbecued millions of pounds of beef, and every one of them could have done a better job at it by applying some science, according to two food chemists who presided over a barbecue on Aug. 17 during a meeting at the American Chemical Society.
Understanding the chemistry of grilling could help us avoid carcinogens, cook burgers in half the time, and pick the perfect beer to go with our favorite sauce, they explained to a roomful of journalists feasting on ribs and brisket.
Cooking over an open flame is a distinctly human activity that makes food easier to digest and may have even helped to spur the evolution of our species. Like the campfires of our prehistoric ancestors, the modern charcoal or gas grill uses heat to change the chemical structure of meat. The heat causes the proteins and sugars in a cut of beef to react with each other, turning the meat brown as tasty new chemicals are formed.
But overcooking meat can be harmful to your health. "You increase your chances of stomach cancer by three times if you order your meat from medium-well to well-done," said Shirley Corriher, a biochemist who writes books on the science of cooking and baking.
The worst offenders, Corriher said, are parents who think that leaving the middle of a solid piece of meat uncooked is not safe. "Mothers unfortunately have instilled in their children to order everything cremated ... so they won't have E. coli," said Corriher. "This is just absolutely dangerous."
Bacteria thrive on the surface of raw meat. But these bacteria cannot penetrate to the inside of a whole piece of beef, poultry, or fish, said Sara Risch, food chemist and principal of the consulting firm Science By Design.
"I happen to like tuna that is just barely seared on the outside," said Risch. "I'm not worried about any food poisoning from that because the inside of that tuna flesh is basically sterile. There are no microoganisms growing in there."
The exception to this is ground beef because its potentially-contaminated surface has been broken up and mixed throughout the meat. But even ground beef can be cooked less to avoid burning, thanks to a trick from John Willingham, whose Memphis barbecue earned him the title the Overall World's Bar-B-Que Grand Champion at the Houston Livestock Show and Rodeo in Texas. While cooking burgers for 50 Cub Scouts, he tried poking holes with his thumb in the middle of the patties.
"The burger got done from the inside-out and the outside-in, got done in half the time, you didn't have to worry about E. coli in the center of the ground beef," said Corriher.
Overzealous efforts to kill surface bacteria often causes meat to go from brown to burnt.
"Some people love that charred flavor, but actually from a safety standpoint it's not really very good for you," said Risch. "When you burn it you actually do form some carcinogens on the surface." These carcinogens, called heterocyclic amines, are a natural result of cooking any animal muscle at high temperatures.
One way to cut down on heterocyclic amines is to prevent flare-ups of large, hot flames caused by dripping fat. "If you pre-boil them, you're going to get rid of a lot of that fat and dramatically reduce the incidence of those flare-ups," said Risch. "You can always boil them in a little beer, that's going to add to the flavor."
Another option is to coat the outside of the meat to prevent it from coming into contact with temperatures over 500 degrees Fahrenheit, which cause the formation of carcinogens. A recent European study showed that using a marinade of red wine can prevent up to 88 percent of heterocyclic amines. Other research has shown that garlic and Cajun-style blackening -- which uses mixtures of herbs and butter -- have similarly protective effects.
The chemists also tackled the ongoing debate between North Carolinians and Texans as to which approach produces the best barbecue -- a vinegar treatment or a tomato-based sauce. Without taking a side, the chemists explained how the two types of barbecue can change how your beer or wine will taste by priming your taste buds.
Our tongues respond to five different types of tastes: sweet, salty, bitter, sour, and umami. Vinegar-based barbecue falls into the salty category; tomato-based sauces tend to be sweeter.
Years ago, Corriher investigated how eating something sweet or salty affects the taste of wine. She found that taking a bite of out of a sweet apple intensified the bitterness in a wine -- mild white wines taste much stronger, and red wines loaded with bitter chemicals become almost overwhelming. Putting a dab of sour lemon or salt on your tongue, on the other hand, had the opposite effect, suppressing bitter tastes in other foods and beverages.
According to her research, sweet barbecue will amplify the bitterness of a bitter beer. "If you're doing the North Carolina vinegar, it's fine, you can have anything because the vinegar is going to knock it out," said Corriher.
She also shared the secrets of her mother's barbecue sauce, which bridges the two schools of thought: ketchup, brown sugar, allspice, and an entire minced lemon, including the peel.
