The Science of BBQ - Carryover Cooking
The science of barbecue explores the way cooking happens when you use different techniques, and there are several very important factors that go into cooking the perfect meal. Selection of the perfect ingredients, the proper method of cooking and finally finishing things off – be it with a good rest, the ideal garnish, or something else. There are a couple of things that happen when you rest meat. One of the most important ones is carryover cooking. But what is carryover cooking and how does it work? Find out how to use the science of carryover cooking to your advantage and ensure that your meals are the best that they can be.
Thermodynamics is the study and understanding of how heat works and how it moves from one place to another – like from the barbecue into your food. The radiant energy from the fire heats the air and the metal surfaces inside the barbecue, which is then transferred to the food on a molecular level. Cooking is occurring through radiation – the light energy creating heat like our infrared burners, conduction – the surfaces in the barbecue is getting hot and transferring that heat to the food, and convection – when heat energy is carried through the air, water or oil and then transferred to the food.
The First Law of Thermodynamics
The first law is something most of us know from high school. Energy is constant. It cannot be created or destroyed, only changed from one form into another.
For example, the flames in the barbecue, the glow from your charcoal, and infrared burners are a form of light energy called infrared radiation and is literally traveling at the speed of light. If it hits the food directly, the food is cooked through radiation, however, there is usually something in the way in the form of sear plates and cooking grids. That infrared radiation heats the metal and air present, and that heat is transferred to the surface of the food.
The Second Law of Thermodynamics
The second law of Thermodynamics states that everything wants to be the same temperature and over time heat transfer will make this true. There is a second part to this, stating that heat cannot pass from a colder body to a hotter one. For example - let’s say you have a hot barbecue and a cold steak - when you place the steak onto the hot grill the only way for that heat from the barbecue is going to go is into the steak. The cold in the steak cannot pass into the cooking grids.
Want to learn more about how cooking on the Barbecue works? Find out more here.
What is Carryover Cooking?
Carryover cooking is what happens when food comes off the grill (or out of the oven, smoker, or another cooker) and continues to cook, even though it has been removed from the heat source. This works through the principles of thermodynamics and can increase the internal temperature of your food by anywhere between 5 and 25 degrees Fahrenheit. Interestingly enough, this is a two-way process where the inside of the food is receiving heat from the outside of the meat, but the outside is also passing heat into the air. Remember the second law stating that everything wants to be the same temperature, so that heat is trying to warm the air around the food.
Size and shape of the food, especially meat, being cooked will play a huge role in how the temperature of the meat is dissipated and how much carryover cooking occurs. The larger the mass, volume, and/or area of the food, the more ability it will have to retain heat. This also translates to uniformity of heat transmission and temperature increase. A whole roast of beef is denser than a single steak and will hold onto more heat. Shape-wise a steak has more surface area to mass/density and heat-dissipating from the outside will happen faster than it would to a roast made from the same muscle group (ie. A tenderloin steak vs. tenderloin roast).
The temperature that food is prepared can change the way heat is absorbed and distributed. Low and slow cooking, like in a smoker, causes the process of carryover cooking to be slower. The hotter the cooking being done through both ambient and implement, for example, searing at 400°F, the hotter the outside of the food will be, and the more carryover cooking will occur.
How to Deal with Carryover Cooking?
Carryover cooking can seem complicated, however, with a little planning and a very good meat thermometer, it is easy to use carryover cooking to your advantage, ensuring the most succulent meals both barbecued and cooked indoors. Paying attention to the temperature of the food you are cooking and removing it from heat within 5°F of finished temperature is important. Allowing that meat to rest before serving is the second part of using carryover cooking to guarantee a delicious meal. Leave that meat thermometer while you rest the meat to ensure that the perfect temperature has been reached.
Resting is an important part of finishing a meal for more than just the carryover cooking. Learn more about Resting Meat.
There is more to grilling and using your barbecue than just flame and heat, food and flavor. Deep science is at work through not just the seasonings changing the composition of the molecules, but the way the heat works through thermodynamics to cook the food, and even that residual heat ensuring that your meal makes it to completion perfectly. What is your favorite grilling technique to achieve the perfect meal? Tell us by sharing your recipes, stories, and photos on our social pages like Facebook and Instagram using he hashtags #NapoleonEats and #NapoleonGrills.