What Is Charcoal

The single most recognizable sign of spring arriving is the smell of barbecue in the neighborhood. Whether you’re proficient in grilling or new to the barbecue world, knowing what charcoal is and using it correctly are essential. Here we explore what charcoal is, its origins, and some other fun uses for the half used bag of charcoal for when summer ends.

Simply put, charcoal is a greyish black, carbon residue resulting from removal of water and other such components from organic matter. It is lightweight, and is made naturally by slowly heating wood and organic materials to around 1000F in an environment with low oxygen.

This process is called pyrolysis or charcoal burning and results in what is called lump charcoal. This lump charcoal is composed largely of carbon. The crucial point here is the low oxygen environment because that ensures that the wood itself doesn’t burn. Instead, what burns are the volatile impurities in the wood, like water, tar, methane and other gases, leaving only ash and pure carbon.

Burning charcoal is more advantageous than burning wood, due to the absence of water, which allows charcoal to burn, giving off negligible smoke, and at higher temperatures, making it perfect for searing at high heat or grilling slowly at low heat. In contrast, burning wood gives off a lot of soot in its smoke due to unburnt carbon particles, steam and organic components. To understand what kind of charcoal and wood gives affects the quality of the smoke, we take a look at the types of wood and charcoal available to us today:

Types of Charcoal:

Lump Charcoal

The natural charcoal, as described above, burns at very high temperatures. It is also a money-saver, because it produces twice the amount of heat as charcoal briquettes. Lump charcoal is 100% natural, lighting very easily and burning cleanly. It is made from hardwood and does not produce a lot of ash. Since it produces more heat, it can get the fire to cooking temperature in a very short amount of time (around 10 minutes). However, on the downside, it also burns for a shorter time than charcoal briquettes.

Charcoal Briquettes

They are round or square pieces of charcoal, made up of constituents like hardwood char, nitrates, lime, starch and coal. It burns more evenly and at a lower temperature than natural lump charcoal, thus lasting longer. Since it is manufactured, it is also more compact than natural charcoal. Let us take a look at the function of each constituent:

• Hardwood Char: The wood char from hardwood does not contain the resins found in soft woods, which allows it to burn for longer and produce a higher temperature.
• Anthracite: This being one of the finest qualities of coal produces negligible smoke and is odourless.
• Lime: Allows for a consistent, even burning.
• Nitrate: The chemical generally used to coat the briquette is sodium nitrate, to facilitate the briquette to be lit easily.
• Starch: It is used as a binder during the manufacturing of charcoal briquettes.

How is Charcoal Made?

People mainly recognize charcoal as an irregular shaped briquette bought from the store, pre-treated and wrapped in plastic. Since charcoal doesn’t have any plasticity, it needs a binding material added to the charcoal dust, on which pressure is applied to form a briquette. Let us take a look at the ingredients used in the making of a charcoal briquette, and the manufacturing process.

The ingredients in the making of a briquette come under the following categories:

• Fuel for heating: This is the component that provides the heat for the briquettes to form. The higher the amount of heat fuel materials, the better the is briquette. Wood charcoal, biomass, mineral carbon, etc are used as fuel materials. Ideally, the material should produce less ash. Around 90% fuel material produces better briquettes which generate more fire.
• Accelerants: Generally 3-4% nitrates are used as accelerants, but depending on the market, it can end up making the product more expensive, since nitrates are priced higher due to them being a fertilizer ingredient. Briquettes need accelerants to burn faster, since their compact structure as compared to lump charcoal implies that they are not able to absorb enough oxygen to combust faster. When nitrates are heated, they produce oxygen (due to nitrates being oxidants) to accelerate combustion of briquettes. However, keep in mind that potassium nitrate and ammonium nitrate are dangerous, and should be avoided.
• Binders: Cassava starch is the best binding material known for charcoal dust. The starch needs to first be gelatinized, which is a fancy word for breaking down the bonds in the starch by immersing it in hot water to form a thick paste. This paste helps the charcoal dust stick together. 5-7% starch is generally required to make briquettes. An alternative to cassava starch is the acacia gum, extracted from the acacia tree.
• Materials for bringing white ashes: The white ashes are used as an indication to the user to show that the briquettes are ready after they are lit in the grill. These ashes come from copious amounts (2 to 3%) of limestone or calcium carbonate. These components, however, reduce the burning rate of the briquettes, so that they burn at a lower temperature for longer.
• Press Release: Chemicals like borax are used to ensure that when a briquette is formed by pressing the charcoal paste, the briquette does not stick to the press. This component is not required if using a simple press machine.
• Fillers: These are components like sand or cement or clay used to increase the weight, volume or density of the briquettes. They normally add no value, produce ash, and are used as a cost cutting measure.

Manufacturing process:

On an industrial scale, the first step is to char the wood. This can be done in a kiln, or in a continuous method. In a kiln, the wood is first loaded and a fire is lit with enough oxygen to ensure high temperatures. The wood is burnt for a week at temperatures between 840 to 950F.
After that, there is a two week cooling period, following which the char, which is the now carbonized wood, is crushed.

The second step is to carbonize the coal. This is typically essential for lower grades of coal. The pulverized coal from the previous step is dried and heated, up to a temperature of 1100 F. This removes most of the volatile components in the coal, after which the coal is cooled by air and stored.

The third step is the actual briquette making process. Components like the charcoal and binder are added in their appropriate amounts in a mixer, where it gets blended properly. This material has a consistency of moist soil. It is then dropped into the press machine, which consists of opposing rollers with indentations to mould the briquette.

The binding agent and roller pressure combine with the moisture content to help the briquettes keep their shape as they are placed on a conveyor which passes them through a dryer which reduces the moisture content by heating them to 275F for 3 to 4 hours. These briquettes are then packed and kept ready for shipping.

In a continuous method, also called the retort method, the wood is passed through a series of ovens such that wood is continuously being taken in to the chambers and charred material is produced at the other end. In contrast to the kiln method, this produces a much larger amount to char per hour. In addition, the continuously consistent amount of smoke can be treated via afterburners, thus controlling smoke emissions from the retort.

History of Charcoal:

In the prehistoric times, cooking over an open fire was the only way we knew to cook meals. Around 200,000 to 40,000 years ago, humans had learnt to build basic hearths with stones arranged in a circle, and for many more years, this became the main method of cooking food. However, the modern barbecue we know originated in the Caribbean, with the first mention around the year 1526. Initially cooking with wood, charcoal soon turned out to be a viable, easier alternative to cooking.

Charcoal has been used since more than 6000 years ago, initially as the fuel of choice to smelt copper. Later it became used widely for smelting iron, once blast furnaces were invented. A popular fuel for blacksmiths, charcoal was also used to extract silver from its ore, and for residential and industrial heating, besides fueling the first railroad engines.

Around 1920, Henry Ford invented charcoal briquettes, triggering the transition to charcoal being used as a cooking material instead of just an industrial fuel. This turned the sawdust and scrap wood produced in his automobile factory into a profitable business, with the added bonus of encouraging people to use cars for outdoor picnics.

Traditionally, wood was piled in a conical mound and covered with dirt or ashes, with air intake holes at the bottom of the pile to produce charcoal. The wood was slowly burnt, and then cooled slowly by blocking the air intake holes. This method produced a large amount of smoke, which were used to mark transitions to various stages by marking the color of the smoke. Starting with a white smoke to signal steam evaporation, the smoke turned yellowish to mark the burning of resins in the wood. The charred wood is signalled by the smoke turning a pale blue, indicating that the char needed to be cooled.

Uses of Charcoal Other Than Cooking:

Charcoal’s first, and most important usage has been as a metallurgical fuel. It is used by blacksmiths and by other applications such as metal extraction, where intense heat was required. It was also used as a black pigment by powdering it. Here we look at some historical uses of charcoal, before moving on to tips for using the half empty bags of charcoal in your kitchen.

1. As a metallurgical fuel: Due to its high temperature of burning and its porosity, charcoal is sensitive to the flow of air, thus allowing control of the heat by moderating flow of air to the fire. It also provides the necessary carbon for the production of iron and steel.
2. As an industrial fuel: Charcoal was used to power early railroad engines, for heating and for iron melting.
3. Cooking fuel: Charcoal was used as a cooking fuel before the Industrial Revolution, where it was replaced by coke, which is baked coal, due to differences in cost.
4. Automotive fuel: Hard as it may be to believe, automobiles have been converted, during scarcity of petroleum, to run on wood gas, produced by burning charcoal in a wood gas generator. These are no longer in use.
5. Carbon Source: Charcoal, specially treated at high temperature to reduce hydrogen and oxygen residue, has been used as a carbon source in various chemical reactions.
6. Cosmetics: Charcoal which has been produced from regular bamboo has been used in a variety of cosmetic products due to its absorptive properties at a microscopic scale. To create charcoal from bamboo, cut the bamboo in small pieces and boil so that soluble compounds are removed. After drying and carbonizing at high temperatures in an oven, raw bamboo charcoal is obtained.
7. Pyrotechnics: A component of fireworks is black powder, which is made from charcoal. Specific charcoals like willow, spruce, and grapevine produce better black powder. These produce golden or dark orange sparks in fireworks.
8. For purification: Activated charcoal is widely used as a filter in industrial processes due to its adsorptive properties for a variety of organic compounds dissolved in gases or liquids. It is also used as a filter in gas masks to adsorb odors and toxins in the air. In the medical industry, activated charcoal is used to adsorb poisons and treat overdoses and flatulence. Apart from this, it has been used as a natural water filter, with the ability to adsorb a wide range of bacteria, viruses, and chemicals from water. Additionally, activated charcoal has been used to treat skin infections by their antibacterial effect, in deodorants by adsorbing odors and excess moisture. The most recent use of activated charcoal is, however, in skin care, with studies reporting that it can help remove dirt, dust, chemicals and toxins from the surface of the skin.
9. Art: Charcoal drawings are a popular technique for artists who enjoy sketching. It normally requires a fixative to preserve the drawing. Three forms of charcoal are used in art:
   • Willow charcoal: Created by burning sticks.
   • Powdered charcoal: It is used to cover large areas of a drawing surface. Erasing over the toned area creates lighter tones, while drawing or sketching over it darkens the tone.
   • Compressed charcoal: It comes in the form of sticks, made of charcoal powder and binder mixed together, with the hardness of the stick depending on the amount of binder used. Charcoal pencils use compressed charcoal.
10. Horticulture: Using charcoal in horticulture has been found to be a technique used by natives in the Amazon to convert useless soil into carbon rich soil. This technique has found resurgence in many sections of American gardening in recent times.

Using Charcoal in Your Home

Now to move on to applications for the unused charcoal in your home.  If you didn’t like any of the above suggestions, here are a few more ways you can use that charcoal instead of stashing it away in some corner of the house waiting for the next summer.

1. In your compost heap: If you have a compost pile in your backyard, you could add some charcoal to it to nourish the soil and increase its carbon content (see point 10 above).
2. To hide scratches: You can use charcoal to rub out scratches on dark wood floors, temporarily hiding them until it can be repaired.
3.  To keep cut flowers longer: Placing a small piece of charcoal in the vase with the cut flowers will help the water stay cleaner for longer.
4. As an air freshener: Placed in perforated bowls or bags, or in open bowls, eliminates odors from the room and keeps air smelling fresh for longer.
5. Keep rock salt and sand from clumping: While storing rock salt and sand for de-icing in the winters, they have a tendency to clump due to the moisture. This can be prevented by adding a few pieces of charcoal to the bags where the sand and salt are stored.
6. Prevent tool rusting: Placing charcoal in your tool box absorbs the moisture and prevents oxidation of the metal, thus preventing rusting.
7. As a growth agent for potted plants: Potted plants, especially orchids, have been observed to have better growth when lumps of charcoal are added to the soil.

Add Wood Chips On Charcoal Grills

To add wood chips on charcoal grills, soak the chips and remove the cooking grate of the charcoal grill. Add your lit charcoal from your chimney starter. After that, drain the wood chips and once the charcoal has turned to ash, scatter the chips over the hot coals. Replace the cooking grate when the chips start smoking. The grill is ready to be used. There are various types of wood chunks that can be used to cook. Here we take a look at the types of wood chunks you can use and what effect they have on the flavor of the barbecued meat:

• Apple wood chips: Best suited for pork, chicken, vegetables or lamb, it imparts a smoky apple flavor to the meat.
• Pecan wood chips: Best suited for chicken, ribs or turkey, it imparts a smoky pecan flavor.
• Cherry wood chips: Imparts a smoky cherry flavor and is suited for chicken, game, lamb, and turkey.
• Hickory chunks: Suited for barbecue, grilling, and wood burning ovens; this is a cleaner burning wood compared to others.

As we can see, charcoal is an incredibly versatile and woefully underrated object, despite having been around for millennia. So next time you buy a bag of charcoal, you’ll hopefully appreciate the wonders this natural compound can perform, from barbecuing to beyond!

As Always, Happy Grilling