Just the mere considered of barbecue’s smoky scents and intoxicating flavors is sufficient to get most mouths watering. Summer is below, and for a lot of people today in the United States that means it is barbecue year.
I am a chemist who experiments compounds discovered in nature, and I am also a lover of food – which include barbecue. Cooking on a grill may perhaps look very simple, but there is a lot of intricate chemistry that sets barbecue aside from other cooking methods and final results in these types of a scrumptious expertise.
Cooking with fireplace
First, it is important to outline barbecue since the time period can necessarily mean distinctive matters in various geographic locations and cultures. Barbecue, at its most standard, is the cooking of foods more than an open up flame. What distinguishes barbecue from other cooking strategies is how heat reaches the food items.
On a barbecue, the scorching grill grates warmth the food via direct speak to by a approach recognised as conduction. The food items also warms and cooks by absorbing radiation specifically from the flames beneath. The blend of heating solutions permits you to sear the pieces of the foodstuff touching the grill while at the same time cooking the components that are not touching the griddle – like the sides and leading – by means of radiating heat. The resulting range of temperatures generates a intricate mixture of flavors and aromas. In contrast, when cooking on a stovetop, there is a great deal significantly less radiation and most of the cooking is finished the place the food items is in immediate get hold of with the pan.
When barbecuing, you can both put the foodstuff directly previously mentioned the flames – what is called direct heat – or farther absent on indirect heat. The immediate cooking method subjects the food items to really high temperatures, as the grilling floor can be wherever from 500 to 700 degrees Fahrenheit (260 to 371 °high temperatures to drive chemical reactions that change food at a molecular level. When you cook meat at higher temperatures – like over direct heat on a barbecue – the first thing to happen is that water near the meat’s surface boils off. Once the surface is dry, the heat causes the proteins and sugars on the outside of the meat to undergo a reaction called the Maillard Reaction. This reaction produces a complex mixture of molecules that make food taste more savory or “meaty” and adds depth to scents and flavors. The reaction and the flavors it produces are influenced by many variables, including temperature and acidity as well as the ingredients within any sauces, rubs, or marinades.
A similar process occurs with vegetables. Barbecuing allows the water to evaporate or drip down without getting trapped by a pan. This keeps the vegetables from becoming soggy and promotes caramelization reactions. These reactions turn carbohydrates and sugars into smaller compounds like maltol – which has a toasty flavor – and furan – which tastes nutty, meaty, and caramel-like.
Char and crisp
Another hallmark of barbecued food is the unique char it develops. When foods are exposed to heat for prolonged periods of time, non-carbon atoms in the food break down, leaving behind the crispy, black carbon. This is the process of burning or charring.
Almost no one likes a completely burnt piece of meat, but little splashes of crispy char flavor can add such depth to foods. Cooking over the direct heat of a barbecue allows you to add just the amount of char to match your taste.
Unfortunately for those who like a little extra crisp, some of the chemicals in charred meat – molecules called heterocyclic amines and polycyclic aromatic hydrocarbons – are known carcinogens. Though the dangers are far lower than smoking cigarettes, for example, limiting the amount of charring on meats can help reduce the risk of developing cancer.
The final quintessential barbecue flavor is smokiness. Cooking over wood or charcoal involves a lot of smoke. Even on a gas grill, melting fats will drip onto the heat source and produce smoke. As smoke swirls around the barbecue, the food will absorb its flavors.
Smoke is made up of gases, water vapor and small solid particles from the fuel. Burning wood breaks down molecules called lignans, and these turn into smaller organic molecules – including syringol and guaiacol – that are mainly responsible for the quintessential smoky flavor.
When smoke comes in contact with food, the components of the smoke can get absorbed. Food is particularly good at taking on smoky flavors because it contains both fats and water. Each binds to different types of molecules. In chemistry terms, fats are non-polar – meaning they have a weak electric charge – and easily grab other non-polar molecules. Water is polar – meaning it has areas of positive charge and an area of negative charge similar to a magnet – and is good at binding to other polar molecules. Some foods are better at absorbing smoky flavors than others, depending on their composition. One way to use chemistry to make food more smoky is to periodically spray it with water during the barbecuing process.
Smoke can contain hundreds of possible carcinogens depending on what you are burning. Only a small amount of research has been done on whether grilled foods absorb enough smoke to pose a significant risk to health. But researchers know that inhaling smoke is strongly correlated with cancer.
While the idea of barbecuing your favorite dish may evoke the feeling of simple pleasures, the science behind it is quite complex. The next time you enjoy the smoky goodness of food from a grill, you will hopefully appreciate the diverse nature of the compounds and reactions that helped produce it.
Written by Kristine Nolin, Associate Professor of Chemistry, University of Richmond.
This article was first published in The Conversation.