Fire is raw energy that results when oxygen unites rapidly with another substance. Usually, oxygen bonds with materials so slowly that combustion doesn’t occur. For instance, when oxygen unites with iron, you get rust (no flames there). But when the same union occurs with gasoline or another petroleum distillate, fire and intense heat are given off. Anything with the potential of bonding rapidly with oxygen in this way is called fuel.
In order for combustion to take place, three things have to be present: fuel, an ignition source, and plenty of oxygen. In a gas grill, these elements are mostly automated and controlled by the fuel knobs or valves, an electric igniter, and a regulated mixture of fuel and oxygen. Lift the lid, open the valves, and push the igniter button (or insert a flame into the match hole), and a gas grill will light instantly.
In a charcoal grill, on the other hand, the essential elements are less regulated. The fuel is often some form of wood: paper, sawdust, twigs, branches, logs, or charred wood (charcoal). Depending on the form of the wood, the amount of energy required from the ignition source to reach the fuel’s ignition temperature varies. In order for a fuel to ignite, its molecules must be moving fast enough to pass into a gaseous phase, so the easier it is to turn a solid fuel source into a gas, the less energy it takes to start a fire.
Paper (wood pulp) takes very little energy to flame; a match will do the trick. Sawdust (ground wood) needs a little more energy; a match still works, but it must be held against the wood longer for combustion to take place. Solid wood is harder still to combust, although smaller pieces require less energy than thicker ones. All of this explains why a wood fire that will last long enough to cook food must happen in stages. The first stage is paper or dry leaves, which ignite easily and spend themselves quickly. They are best used as tinder to create enough energy to ignite second-stage kindling (small twigs, etc.), which in turn must burn hot enough and long enough to light third-stage branches, followed by fourth-stage logs. The denser and larger the wood, the harder it is to ignite, but the longer and hotter it will burn. Sometimes a distilled petroleum product, like lighter fluid, is soaked into hard-to-ignite solid fuels in order to start their combustion more quickly. The following chart shows the approximate amount of energy it takes to ignite common fuels.
Preburning (charring) wood makes it easier to ignite. To make charred wood or natural lump charcoal, wood is burnt until it is reduced to carbon. At that point, about 60 percent of its potential energy has been spent, so a charcoal fire will burn out faster than a wood fire. It’s a trade-off, but one that is advantageous to most of us who don’t have hours to nurse a wood fire until it turns into a thick, glowing bed of coals.
Starting a Wood Fire
Three things happen when wood burns: Water in the wood evaporates, the wood smokes, and the wood gradually burns down to hot coals. Freshly cut logs are about 50 percent water and don’t burn easily. Seasoned or dried wood is about 20 percent water and burns more easily because less energy (heat) is required to evaporate the water.
The goal is to light a wood fire quickly so that it produces minimum smoke and maximum combustion. For this, you need dry wood and an initial burst of heat from a match or other fire starter. There are dozens of ways to construct a wood fire. We’ll discuss only the two primary ones: the bottom-up method and the top-down method. In both methods, the dry fuel is layered from most to least combustible, and then it is lit. The fuel can be layered on a flat surface, such as the cleared ground in a pit or fire ring, on a fireplace floor, or on the floor of a grill. Preferably, it will be layered on an elevated grate. Elevating the wood allows for better airflow and faster, more complete combustion. If you don’t have a fire grate, put two or three medium-large logs on the flat surface and layer the fuel on top of this makeshift log grate.
BOTTOM-UP METHOD Clear the area and put down a layer of crumpled paper, dry leaves, or another easily combustible fuel (crumpling the paper helps air to reach all of its surfaces). Next put on a layer of small twigs, lath, or other thin wood, followed by increasingly thicker branches and small or split logs. Then ignite the paper at the bottom with a flame or other fire starter. The wood ignites from the bottom up. Save the largest logs to add to the fire after it is well established. This method works best with a tepee construction, layering each type of fuel in a cone shape. If you’re on soft ground, it helps to drive a single branch into the ground in the center of the tepee to help hold up the sides. As the wood burns, the cone will burn and eventually fall as hot coals, at which point larger logs can be tossed onto the coals. Because the cone is rather tall at first and then falls, the bottom-up method is best suited for campfires or fire bowls where there is no limit to the vertical space and plenty of room for falling embers.
TOP-DOWN METHOD Less popular but more impressive, the top-down method is the bottom-up method in reverse. Put your largest logs on the bottom, followed by layers of increasingly combustible split logs, branches, twigs, and other kindling. Paper or dry leaves go on the top. Light the top and, believe it or not, the fire ignites from the top to the bottom. This method works best with a box or crisscross construction made by positioning two large logs on the bottom parallel to one another. Position smaller or split logs on top of and perpendicular to the large ones to create a box shape. Continue crisscrossing layers of increasingly combustible small branches, twigs, lath, and finally paper or dry leaves on top. Because the box is more stable and shorter than the cone, this method works well in fireplaces and shallow grills where there is limited vertical space in the firebox. A top-down fire is also less likely to collapse and smother itself.
Whichever method you choose, allow the wood fire to burn down to a bed of brightly glowing embers before cooking over them. If the embers start to lose their heat, add more wood to the fire. For fireplace and campfire cooking, it helps to create two areas of the fire—a refueling area at the back or side and a cooking area at the front or other side. Add fresh wood to the refueling area and rake hot coals into the cooking area to create a level bed of embers.
Starting a Charcoal Fire
Charcoal is wood that’s already been burned. It may come in the form of briquettes or lump charcoal. The easiest way to light charcoal is to stack it up so that oxygen can quickly and easily travel upward through the coals. You can also use lighter fluid or another petroleum distillate, but most grilling aficionados avoid lighter fluid, claiming that it gives food a petroleum aftertaste. The truth is that once lighter fluid has burned off and the coals are glowing orange-red, there is no petroleum left. That is, unless you happen to squirt some lighter fluid onto the side of the grill, where it will very slowly emit petroleum fumes that can become infused in your food. If you choose to quick-start a fire with lighter fluid (which may be the easiest way if you’re facing a huge mound of coals to light for a sizable grill), just be sure to squirt only the coals and let them burn to a glowing orange before you start cooking over them.
To ignite charcoal without petroleum, you have three basic options: Stack the coals in a pyramid, use a chimney starter, or use an electric starter. A pyramid of charcoal takes 30 to 40 minutes to burn down to a red-orange glow worthy of cooking over. Using an elevated fire grate and layering the pyramid with sheets of newspaper helps somewhat. But a chimney starter (our favorite method) cuts lighting time nearly in half because it increases the oxygen flow to the coals. The coals also light more evenly than with the pyramid method, and you don’t need lighter fluid.
Chimney starters look like large, tall coffee cans with a divider near the bottom, holes on the sides, and a handle. See the next section for instructions on how to use one. If using an electric starter, insert the metal loop of the starter into the bottom of a pyramid of coals, then plug in the starter (use an extension cord if necessary). The hot metal ignites the coals and they, in turn, ignite each other. Remove the starter when it is surrounded by glowing orange coals. The pyramid of coals should be ready for cooking in 30 to 40 minutes.
How to Maintain a Live Fire
We call charcoal and wood fires “live” fires because they are not as controlled as the flame produced by a gas grill. Getting a live fire to ignite is one thing; keeping it burning is another. Remember: The life of a fire is dependent on having enough oxygen to bond with the amount of fuel on hand. If there is only a small amount of oxygen, a fire may start, but it won’t last long, which means the art of fire tending requires a constant flow of oxygen to the flames. To create that flow, there must be air all around the fire, which is why fires are built on grates to raise them above solid ground.
In a kettle grill, the fire grate is suspended about halfway between the grill floor and the grill grate, leaving ample air space under the fire. Vents on the bottom and on the lid of the kettle also allow air to flow to the fire, even when the grill is covered. In a box grill, or hibachi, the fire grate is much closer to the floor of the grill, but there are air vents on the sides and bottom; and because hibachis are not lidded there is ample oxygen entering from above.
With a wood fire, using an elevated grate improves access to air from underneath. Start with a tepee or box construction for the best airflow (see the illustrations on page 31). As the fire burns, adjust the position of the logs to maintain ample air space around each log. Eventually, the wood will oxidize enough so that it no longer contains enough fuel to flare, at which point it will have reduced to glowing embers and will no longer need a steady supply of oxygen.
Be sure to refuel the fire before it gets too low. For a wood fire, add dry, seasoned wood to the hot coals while the coals are glowing red and hot enough to ignite the wood. To increase airflow around a fresh log, it may help to prop it up on a half-burned log rather than simply laying it over the top. In a charcoal grill, you can add fresh charcoal or prelit charcoal using a chimney starter.
If necessary, you can force air onto the fire to increase the oxygen flow and help the fire light more quickly and evenly. We’ve tried everything, from blowing air through our mouths to using a bellows, waving a magazine, positioning the fire toward the wind, using a hair dryer, and blasting the fire with a leaf blower. All of these methods work, but those that force the most oxygen the most quickly onto the fire work best. In our experiments, the leaf blower won.
Even if you supply sufficient air, a piece of wood will never burn completely. There will always be elements within the wood that cannot bind with oxygen. These incombustible particles become ash if they are large, and if they are small enough to become airborne, they form most of the visual and aromatic components of smoke. The amount and type of incombustible particles in the wood determines the quality of its smoke. Because lump charcoal and charcoal briquettes are almost pure carbon, they combust more completely than wood, leaving less (but finer) ash behind and producing less aromatic smoke. Soot, a black residue that can be left on grilled food or around the edges of a fire, is not a by-product of burnt wood; rather, it is unburned carbon, and its presence indicates that there was insufficient oxygen for the amount of fuel. Check your grill lid for black soot. Typically, you’ll find more soot buildup when you grill with the lid down or via indirect heat, because these methods restrict the oxygen supply.
The Science of Heat Transference
Even the best-built fire will do you no good if the heat doesn’t get to the food. There are three methods of heat transference that take place during grilling. Understanding them is basic to mastering all grilling techniques.
Conduction
Heat makes molecules move faster. The faster they move, the more likely it is that they will bump into an adjacent molecule and transfer heat from one molecule to the other. This straightforward interchange of energy is called conduction. It is the basic way that heat moves from the fire to the surface of the grill grate, through the grill grate, and, finally, into a piece of food.
Although conduction is at play in all areas of the grilling process, the way heat moves through a metal grate is different than how it moves through a slab of meat, for instance. Metals are particularly good heat conductors because, even though most of their molecules are tightly bound, they contain electrons that jump easily from one atom to another. This mobility of electrons moves heat quickly through metal grilling equipment. But meat and other grilled ingredients don’t heat through as efficiently.
Before a steak even touches the grill, the grill grate should be thoroughly heated, which ensures that the surface of the meat gets a blast of energy at the onset of cooking. That’s why most grilled steak recipes direct you to preheat the grill. For direct grilling, a hot grill grate is necessary to force heat deeply into the meat as quickly as possible; once the heat moves from the highly conductive metal grate into a less conductive steak, the heat transference slows down dramatically. The surface of grilling meat continues to receive the bulk of the available heat energy throughout the cooking process, passing it along very gradually, which allows us to produce a thick crust on the surface of a steak while keeping the interior moist and rare.
The amount of heat coming from the fire itself has little effect on how fast that heat transfers through the meat; a hotter fire simply makes the surface crustier. So the more well-done you like your meat, the lower the temperature must be to ensure that the center cooks through without scorching the surface. Likewise, large, thick roasts need to be grilled away from direct heat to give heat traveling through the meat enough time to reach deep into the center.
Convection
While conduction moves heat to food through the metal grill grate (and throughout the food itself), convection moves heat around food. As the fire heats air inside a closed grill, the molecules in the air move faster. Moving molecules take up more space than still ones, which makes the hot molecules rise. Air currents develop, circulating hot air toward the top of the grill, which forces cooler air down toward the fire, where it is heated, causing it to rise, and so on. Convection is not a primary method of heat transference in grilling (especially with no grill lid), but it does account for some of the cooking that takes place in indirect grilling, in which food does not come into direct contact with a hot grill grate or a radiating flame.
Radiant Heat
Radiation is harder to understand than conduction or convection, because this type of heat never touches the food, yet it is the principal form of heat transference in grilling. The best way to grasp the process of radiant heat is to think of the sun. The sun’s heat radiates through space to the earth, warming the planet. Along the way, it doesn’t heat up the void of outer space, as it would if convection were taking place, and there are no metal wires traveling from the sun to the earth, conducting the heat to us. In radiation, energy is passed from one atom to another in the form of pure energy, until it comes in contact with a convecting fluid (like our atmosphere, in the case of solar energy) or a conducting solid (like a hamburger, in the case of grilling), where its energy manifests itself as heat.
Radiant heat is invisible (a good reason why it’s hard to visualize). It is one of many forms of radiant energy that are used extensively in everyday life: Radio waves, TV waves, microwaves, visible light, and X-rays are all forms of radiant energy with different strengths.
Radio and TV waves are so weak (105 to 109 cycles per second) that they need metal antennas to speed up their movement in order to be transmitted or received. Microwaves are strong enough (109 to 1011 cycles per second) to affect polar molecules (like water), and since most food is largely water, microwaves can be used in cooking. Infrared heat (1011 to 1014 cycles per second) is the only section of the spectrum that feels hot; the waves in this section are strong enough to melt fat, coagulate protein, caramelize sugar, and gelatinize starch, as well as boil water. Visible light is stronger (1014 to 1015 cycles per second) than heat radiation; it is powerful enough to change the pigments in our skin and cause fats to become rancid.
Ultraviolet rays (1015 to 1018 cycles per second) can burn our skin, damage our DNA, and cause the development of malignancies. X-rays and gamma rays (more than 1018 cycles per second) ionize molecules by stripping electrons from them; they are strong enough to kill microbes, making them a useful form of radiation in industrial sterilization processes.
Visible light (the only form of radiant energy that we can see) occupies a small area of the spectrum and can be divided into seven wavelengths, which appear to our eye as different colors; red is the weakest and violet is the strongest. Radiant heat energy that is weaker than visible light is called infrared (below red). Ultraviolet (beyond violet) is what we call radiation that is stronger than visible light. The colors of fire correspond to this energy spectrum, ranging from orangey red to blue-violet. Obviously, flames are visible, but we have already said that radiant heat is invisible. Does that mean that fire isn’t really hot? Sort of. The colorful parts of a flame are stronger forms of radiant energy than the invisible heat rising from them, but the area of heat surrounding a flame is hotter than the flame itself.
Although the principles of conduction, convection, and radiant heat help us to understand how grilling works, in actual practice these principles are not as clear-cut. They all occur simultaneously. The flow of heat from fire to grill grate is radiation. The heating of the grate itself is conduction. The heating of the food’s surface is a combination of conduction from the grill grate, radiation from the heat flowing between the bars of the grate, and convection of the air around the food (especially when the grill is covered). As heat moves through the interior of the food, it is being transferred from one molecule to another by conduction and by convection as heated juices begin to circulate through the ingredient.
Most grilling techniques were developed long before the science of heat transference was understood. But even a basic understanding of the science behind cooking food over an open flame will help you to master the techniques of grilling.
Mastering Grilling Techniques
Grilling and barbecuing are two distinct methods of dry-heat cooking. Grilled food is cooked quickly over direct, high heat. Barbecued food is cooked slowly via indirect, low heat with plenty of smoke. Several other grilling methods fall somewhere between these two extremes, including indirect grilling, rotisserie grilling or spit-roasting, smoking on a grill, and grilling right on the coals. Here’s how to master each technique.
Direct Grilling
This method is probably familiar to you. You cook food directly over a fire (charcoal, wood, or gas) on a hot grill grate that’s set 2 to 6 inches above the flame. Direct grilling is similar to broiling, except that the heat comes from below instead of above and the hot grill grate creates dark marks on the food’s surface. Use this method for foods that will sear on the surface and cook through to the center in less than 30 minutes, including hamburgers, hot dogs, sausages, steaks, chops, poultry parts, fish fillets and steaks (and small whole fish), shellfish, vegetables, fruits, doughs, and other small or tender foods. Larger or more dense foods may burn on their surface before the interior is cooked. Save these for another grilling method.
To set up a gas grill for direct grilling, simply heat it to the desired temperature, which is usually medium-high heat (about 450°F). Make it easier to control the heat by setting up two or three areas on the grill for high, medium, and low heat. On a charcoal grill, rake the hot coals into a bed that’s 3 to 4 inches thick on one side and 1 to 2 inches thick on the other. Use the higher-heat area to sear meats and grill vegetables or other quick-cooking foods. Move foods to the lower-heat area if they start to burn or to finish cooking them. You can also use the lower-heat area for toasting breads. See the Direct-Grilling Guide on page 41 for more details on setting up charcoal or wood grills for various heat levels.
Closing the grill lid traps heat and smoke, which speeds the cooking and infuses the food with more smoke flavor. For these reasons, we usually close the lid when direct grilling. (If your grill doesn’t have a lid, improvise by covering the food with a disposable aluminum pan.) At times, however, the food cooks so quickly that there’s little reason to close the lid. Leave the lid off for thin, small, or very tender foods that cook in less than 5 minutes, such as sliced summer squash, boneless chicken breasts, shrimp, and thin fish fillets.
Indirect Grilling
This method works best with bigger or denser foods that take more than 30 minutes to cook, including beef brisket or whole beef tenderloin, pork shoulder or loin roasts, whole chickens and turkeys, and large whole fish. Instead of putting food directly over the heat, you keep the food away from the heat so that it has time to cook through to the center without burning on the surface.
To set up a charcoal grill for indirect grilling, make a split charcoal bed by splitting the coals on opposite sides of the firebox and leaving a large, empty space in the middle. Or you can rake the coals to one side and leave the other side empty. We find that a split charcoal bed provides more even heating because the heat surrounds the food. But if your grill is small, you may get a larger unheated area (for larger roasts) by raking the coals to one side instead of two. Either way, put the food over the unheated part of the grill and close the lid. The indirect heat of the coals becomes trapped in the grill, surrounding the food and slowly cooking it, similar to the way roasting works in a conventional oven.
For fatty cuts of meat, like brisket and pork shoulder, it helps to put a disposable aluminum drip pan under the food between the coals, to catch dripping fat and minimize flare-ups. When indirectly grilling lean or low-moisture foods like skinless poultry roasts or pork tenderloins, we sometimes pour flavored liquid into the pan, such as beer, wine, stock, or citrus juice mixed with seasonings. As the liquid heats, the rising steam keeps these foods moist and infuses them with subtle flavors.
If your grill doesn’t have a lid but does have an adjustable grill grate (as on a flat charcoal grill or open wood-burning pit), set the grill up for indirect grilling by raising the grill grate 1 to 3 feet above the coals. You won’t be able to trap heat or smoke, so plan on increasing the cooking time and losing some smoke flavor.
A single chimney starter full of coals will burn out after 45 minutes to 1 hour of indirect grilling. Add fresh coals by lighting a new batch of coals as the old ones begin to die down. Pour the new hot coals right over the old ones and continue cooking.
If you don’t have a chimney starter, put fresh unlit coals over the old hot coals and leave the lid off the grill until the new coals begin to ash over.
Many charcoal grill grates come with hinged sides, so you can easily add fresh coals to each side. If your grate doesn’t have hinges, lift off the entire hot rack and the food with well-insulated or heatproof grill gloves. Put the hot rack of food over foil on the ground or another heatproof surface, add your fresh coals, and then return the racked food to the grill.
Indirect grilling is similar on a gas grill, except that you light some of the burners but leave the others off. If your gas grill has two burners, light one burner and put your food over the unlit burner. If your grill has three or more burners, light the outside burners and put the food over the middle unlit burners. When using indirect grilling for fatty cuts of meat on a gas grill, make sure the grease catcher is empty or put a drip pan beneath the roast.
The grill lid is a key element of most indirect grilling. It traps heat and smoke, increasing the temperature inside the grill and infusing food with smoke flavor. Keep the lid down as much as possible. Every time you lift the lid, heat escapes, lowering the temperature inside the grill and lengthening the cooking time. See the Indirect-Grilling Guide on page 41 for a summary of setting up charcoal or wood grills for various levels of indirect heat.
Rotisserie Grilling
A form of indirect grilling, rotisserie cooking positions food on a spit above or in front of the heat, where the food slowly rotates. This method produces incomparably moist and evenly browned whole birds, roasts, and ribs. As the meat turns, the external fat gradually melts and rolls around the meat, basting the meat and keeping it moist. Rotisserie-grilled meats are, in effect, self-basting; but if you notice any dry spots on the meat, brush a little oil over the area to ensure even browning.
Rotisseries are available for most gas and charcoal grills. Each one works a little differently; set yours up according to the manufacturer’s directions. In most cases, that means sliding the food onto the spit of the rotisserie and then securing the food with the rotisserie skewers. Be sure to push the skewers firmly into opposite sides of the food to fasten it to the spit rod. Then you put the skewered food into the rotisserie assembly. The food should be suspended 6 to 12 inches away from direct heat and turn freely as the rotisserie rotates. You may need to remove your grill grate to allow room for the food to rotate unobstructed.
Spit-roasting is another name for rotisserie grilling, but it’s usually done on a larger scale with primal cuts of meat or whole animals. Most often, spit-roasting refers to animals suspended several feet over burning coals and slowly turned by hand or a motor.
Adding Smoke
Many people associate the aroma of wood smoke with grilled foods. But gas grilling adds no wood smoke flavor, and charcoal adds only a wisp. It’s true that you get some smokiness from dripping fat in a gas grill, but if you really want to get smoking, you need to burn wood. The traditional way is to build a wood fire (see page 31). The modern way is to add wood chunks or chips to your gas or charcoal grill.
Wood chunks and chips work best when using indirect grilling to cook large or thick foods that will need at least 30 minutes of cooking time. That gives the food time to absorb the smoky aromas. But you can also infuse smoke flavor into small, thin, or delicate foods by smoking them over the unheated area of your grill and then moving them to the heated area to cook through.
Dry wood chips and chunks ignite quickly and incinerate when placed on hot coals. To extract the maximum amount of smoke, slow down the rate of combustion by soaking the chips in water for at least 30 minutes, preferably 1 hour. The longer you soak wood chips and chunks, the longer they’ll smolder before burning up. Soaking also helps to maintain a steady temperature in your grill. Even though you are adding fuel to the grill in the form of wood, the reduced combustion rate caused by soaking prevents the fuel from igniting and raising the grill temperature. Wood chips or chunks can be soaked in a bucket, a bowl, a heavy-duty plastic bag, or almost any pool of water. For subtle aromas, use a flavored liquid such as beer instead of water.
Barbecuing
Smoking on a grill begins to tread into the domain of barbecue, another culinary arena with its own techniques and traditions. As we mentioned earlier, grilling uses high, direct heat and barbecuing uses low, indirect heat. But the hallmarks of barbecue are billows of thick wood smoke and long cooking times—up to 24 hours in some cases. Here’s a quick look at barbecuing, which is mostly outside the scope of this grilling book.
Traditionally, barbecued foods are cooked in a pit or smoker with a separate (offset) firebox. With the heat in one chamber and the food in another, the food cooks by the relatively cool heat of smoke generated by the wood rather than by the radiant heat of burning coals. In the cooking chamber, the temperature remains very low (200° to 225°F) throughout the entire cooking time. This low temperature allows foods to cook very slowly without burning, which is a key factor in dissolving the tough connective tissue that surrounds the muscle fibers in relatively tough meats such as brisket and ribs. It simply takes time for these connective tissues to gradually dissolve and add moisture to the meat. If brisket, for instance, were cooked quickly over high heat, it would be leathery and unpalatable. But when barbecued low and slow, it becomes meltingly tender and succulent. Cooking slowly by the indirect heat of smoldering wood also infuses the meat with deep, smoky aromas.
Cooking in the Coals
Here’s a nifty grilling technique. Dispense with your grill grate altogether and put the food directly on the hot coals. Steaks and chops cooked this way quickly develop a thick crust and amazing flavor due to the deep browning created by the intense heat right on the surface of the burning embers. This method also works well for dense foods with thick skins, such as root vegetables and tubers.
To grill steaks and chops in the coals, you have to use lump charcoal, wood chunks, or logs, all of which create relatively large ashes. Avoid briquettes, which burn down to such a fine ash that the ashes stick to the meat and make it taste sooty. Before adding food to hot coals, you have to blow off the excess ashes. Rake the coals to a somewhat flat bed, and then blow off the ashes with a leaf blower, a hair dryer, a portable fan, or a magazine and a strong arm. Put the meat directly on the coal bed and cook until nicely crusted, about 3 to 5 minutes per side. Season the meat as you turn it, then remove it from the coals and pick off any loose ash.
To grill root vegetables in the coals, bury the unpeeled vegetables in the hot embers and cook until tender when pricked with a fork or knife, 40 to 60 minutes, depending upon the size and density of the vegetable. The skin will char to an inedible blackness, but the flesh inside will be tender, moist, and smoky. And you’ll win raves from whoever sees you pull off this feat of grillmastery.
Wrapping
Food can be wrapped in lotus leaves, grape leaves, banana leaves, corn husks, aluminum foil, or almost any other wrapper that will stand up to the heat of the grill. It’s a useful technique for delicate foods like fish or loose foods like ground meat that can crumble easily during grilling. Complete wrapping also traps moisture inside the wrapper so that food steams, cooks more quickly, and becomes infused with the subtle flavor of the wrapper. Most wrappers are soaked in water before wrapping to prevent them from burning. Use the technique of wrapping with direct or indirect grilling.
Cooking on a Plank
Thin, delicate foods such as fish fillets can stick to the grill, break apart, and become difficult to serve. A wood plank solves these problems and adds smoky flavors to the food. It also allows delicate foods to cook more gently and gradually because the wood forms a barrier between the food and the flame. This technique is used most often with salmon fillets
To grill on a plank, choose a relatively thin (about ¼ inch thick) plank of wood that is wide and long enough to accommodate the food you are grilling. Cedar and alder are the most common wood planks used for grilling, but fruit woods such as apple and cherry also work well. Soak the wood plank in water for at least 30 minutes–and preferably for 1 hour—so that the wood smokes and smolders instead of igniting on the grill. Put the food on the plank, brush with a glaze or add other seasonings, and then put the planked food on the grill grate and close the lid. When cooked through, remove the planked food to the table and serve. The bottom and edges of the plank will be charred, so you may prefer to put the planked food on a cutting board or large platter rather than directly on the table. Serve the food from the plank, dividing it into portions as necessary.
Instead of using a solid wood plank, you can try using wood “paper.” These thin, pliable sheets of wood are wrapped around the food, which allows you to turn the food for more even heating and delivers the woodsy aromas to all surfaces of the food. Sheets of wood need to soak for only 5 to 10 minutes, instead of 30 minutes to 1 hour. They make a good choice for individual or smaller pieces of food.
Mastering Temperature
The temperature of any fire is determined by its ratio of fuel to oxygen. Add plenty of both fuel and oxygen and the fire gets blazing hot. Increase the fuel but restrict the oxygen, and the fire burns slowly. Increase the oxygen but restrict the fuel, and the fire burns quickly. The outside air temperature and wind can also increase or decrease the temperature of the fire.
Finding the right temperature for the food you’re grilling is easy on a gas grill because the fuel-to-oxygen ratio is largely predetermined by the gas flow. Your variables here are the knobs and the lid (and the weather, but there isn’t much you can do about that). For the highest heat on a gas grill, crank the knobs on full blast and put the lid down to trap the heat. For the lowest heat, set the knobs to low and close the lid. For varying heat levels, set one burner to high, set the second to low, and if you have three burners or more, set the others to medium. You can also use the upper warming rack for low heat.
With a charcoal or wood fire, you still manage the fuel-to-oxygen ratio, but you have a few added variables: The type of fuel (denser woods burn hotter than less dense woods), the thickness of the coal bed, the amount of potential energy remaining in the burning coals (which is roughly determined by their appearance), and the vents on the firebox and lid of the grill. Adjusting the temperature is a matter of making a thicker or thinner coal bed and managing the airflow with the grill lid and vents. If you spread a fresh layer of hot coals to about a 4-inch thickness, you’ll have a blazing hot fire at roughly 650°F. As the coals burn and turn to ash in a wood fire, their color will change from bright orange to dull red, with increasing amounts of gray ash. Regulate the temperature by raking the coals into a thick or thin bed (for high or low heat), adding fresh coals, and opening, partially opening, or closing the grill vents and lid. Opening the vents and lid raises the temperature by increasing oxygen flow. Closing them lowers the temperature by cutting off the oxygen supply. The charts that follow explain how to create varying levels of heat for both direct and indirect grilling with charcoal or wood.
Judging Meat Doneness
The two parts of a muscle—muscle fiber and connective tissue As meat heats, the protein in the muscle fibers becomes firmer and more opaque, and the collagen in the connective tissue melts. We can use either of these changes to determine the doneness of a piece of meat, and the one you use depends on the meat you’re cooking.
Tender meat tends to have very little connective tissue. Most steaks are soft enough to bite into when raw, which allows us to judge their degree of doneness solely on the changes that happen to the protein in the muscle fibers as they heat. Raw meat protein is wet, translucent, brightly colored, and soft. As it gets warmer it becomes drier, more opaque, browner, and firmer. The hotter the meat gets, the more these physical changes manifest themselves, which allows us to equate the look and feel of a piece of cooked meat with specific temperatures. For instance, at 120° to 125°F, the center of a porterhouse steak is juicy, bright red, glistening, and tender; we call that rare. At 135° to 140°F, the center is moist, pink, matte, and resilient; we call that medium-done. Raise the interior temperature to over 165°F and the meat becomes dry, tan, dull, and firm—in other words, well-done.
When judging the doneness of tough meat that has a lot of connective tissue, we do not have the luxury of using the changes in muscle fibers as our guide. Tough meat is done cooking when it is tender (period!); there is no such thing as a rare, medium-rare, or medium-done brisket. Tough cuts, like brisket or chuck, are finished cooking when (and only when) the collagen in the connective tissue has melted enough to make the meat tender enough so that you can pierce it easily with fork. For that reason you don’t need to take the temperature of a tough meat to test its doneness; if it is tender, it is ready. Since collagen starts to dissolve at around 160°F, tough meats will not show signs of tenderness until they are in the medium-well to well-done stage. The other element necessary to tenderize collagen is moisture, which is why tough meats are grilled slowly and basted frequently with a mopping liquid.
Grinding tough meat automatically tenderizes it by breaking the connective tissue into small pieces, but that doesn’t mean you can cook it less than its tougher whole-muscle counterpart. During grinding, the surface and interior of a piece of meat are mixed together, causing bacteria on the surface to become dispersed throughout the batch, which is why it is not advisable to eat any ground meat that is not cooked to a temperature of at least 145°F. The U.S. Department of Agriculture (USDA) recommends 160°F to ensure that all areas of the food have reached a temperature of 140°F or higher, but we have found that at that temperature all of the moisture is gone as well. We prefer to stop the cooking of beef burgers at an internal temperature of 150°F; the meat will be slightly pink in the center and still relatively juicy. If you have any reason to doubt the safety of the ground beef you are using, you are welcome to cook your burgers a bit longer, but as long as the interior is above 140°F all harmful bacteria should be neutralized.
Judging Produce Doneness
Grilled vegetables and fruits develop wonderful flavor due to their high sugar content. The sugar quickly caramelizes on the grill, creating complex flavors that are impossible to achieve by moist-heat cooking methods such as boiling or steaming. Judging produce doneness, however, is primarily a matter of texture. Most fruits and vegetables are done grilling when they are hot, crisp-tender, and lightly grill-marked. By crisp-tender, we mean that the plant tissues have retained enough cellular structure and moisture to be somewhat crisp, yet the cell walls are weak enough to be tender and palatable. When a plant is heated, its cell walls begin to break down and lose structure and moisture, becoming increasingly soft. As the internal temperature rises, the texture of grilled produce goes from firm and crisp to crisp-tender to soft and mushy and finally to dry and carbonized. That middle stage of crisp-tenderness is often the best-tasting for grilled produce.
Most fruits and ripe vegetables taste crisp-tender when raw, so take care not to overcook these delicate foods on the grill. Tender vegetables can quickly go from juicy and nicely grill-marked to limp and overly charred. When in doubt, err on the side of undercooking produce. Brief grilling over medium-high or high heat is usually all it takes to soften plant tissues to the crisp-tender stage. Denser vegetables with tough fibers, particularly root vegetables such as beets, should be cooked until fully tender when tested with a fork.
Like other ingredients, fruits and vegetables can be grilled to tenderness using a variety of methods: Direct heat, indirect heat, in the coals, or wrapped in foil. See the Vegetable-Grilling Guide on page 260 and the Fruit-Grilling Guide on page 306 for detailed information on how to grill specific types of produce.
Judging Doughs’ Doneness
Flatbreads like those for pizza and naan grill up beautifully. The doughs for these thin breads cook quickly (1 to 3 minutes) and develop a wide area of crisp crust. We prefer to grill flatbreads directly on a hot grill grate to expose the dough to as much flame as possible. But you can also use a perforated grill rack, which acts more like a baking sheet. To grill topped flatbreads like pizza, you grill the dough on one side before adding the toppings. Then you flip the dough, put the toppings on the grilled side, and slide the dough back onto the grill to brown the underside. Covering the grill is essential to bring heat to the cheese on top so it will melt. You can also grill thicker flatbreads like focaccia without flipping them. The process is more like grill-baking because you use a perforated baking sheet and cover the grill to trap the heat, as in an oven.
The high heat of the grill rapidly vaporizes the moisture in flatbread dough, creating air bubbles that puff up the dough. Grilled flatbreads are done when puffed, lightly grill-marked, and matte rather than shiny on the surface. Untopped flatbreads such as naan will form several bubbles across the surface, while topped flatbreads like pizza will puff up where there are no toppings, such as at the edges.
Yeasted bread loaves can’t be baked on a grill, but slices can be toasted. Bread slices are often used to make grilled sandwiches such as panini. These breads are usually toasted over medium to medium-high heat and are done when lightly browned and crisp on the surface. The same goes for toasting cakes and pastries, although the higher sugar content can cause cakes and pastry to brown more quickly, so we usually toast these over medium to medium-low heat.
Resting
As foods cook on the grill, they lose moisture and become dry. This process begins on the surface of the food (which is closest to the heat) and gradually progresses toward the center. Moisture either evaporates or is driven toward the center of the food. So when any food is removed from the grill, it is less juicy on the surface than it is at the core. Letting the food rest before cutting allows moisture to redistribute from the center back toward the surface. If you cut into steak immediately after grilling, the moisture will be unevenly distributed: The surfaces will be drier than the center. Immediate cutting also drains excess juices at the center because the saturated muscle tissues cannot hold the extra juices that were driven there.
For the juiciest-tasting grilled food, allow it to rest after grilling and before cutting. The thicker the food, the longer it should rest. The juices in a 1-inch to 2-inch-thick steak will redistribute after 5 to 8 minutes. The juices of a thick roast or small whole bird will redistribute in 10 to 20 minutes. Large birds such as turkeys and whole animals like lambs and hogs should rest for 30 minutes after grilling.
Written by Andrew Schloss and David Joachim in "Mastering the Grill - The Owner's Manual for Outdoor Cooking", Chronicle Books, San Francisco, USA, 2007. Digitized, adapted and illustrated to be posted by Leopoldo Costa.