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Charcoal and How
to Make It Way, way,
way back even before modern man evolved, our precursors discovered fire.
After a few painful encounters, they learned how to manage, preserve,
transport and rekindle fire and how to cook meat. Along the line they also
discovered that if they covered live coals with dirt, thereby excluding air,
they could make charcoal. It was light, easy to transport and store and easy
to relight. They soon realized that charcoal is a concentrated source of heat
that is better for cooking than raw wood because it gets hotter and there is
very little smoke. Charcoal can even be used in a shelter or cave provided
there is enough ventilation to avoid a buildup of deadly carbon monoxide gas.
This is why teepees and yurts work so well. As man learned to control fire
and smoke, barbecue, the epitome of Neanderthal cuisine, became a
possibility. Charcoal
is simply wood, or other organic matter, burned to coals and then deprived of
oxygen to stop pyrolysis, or raw organics heated in an oxygen-deprived retort
until nothing is left but char (carbon). Properly made it burns hot and clean
with little smoke or ash. Once lit, it functions just like live coals and is
the best heat source for grills, smokers and barbecue pits. Natural charcoal
imparts little smoke or flavor as most of the volatiles have been burned
away. Primitive man learned that if enough air is forced through burning
charcoal, it will produce sufficient heat to melt rocks and separate metals.
Gold, silver, copper, bronze, iron and steel were all initially extracted
from rocks in charcoal-fired furnaces. Metals were then softened in
charcoal-fired forges to be worked into useful or artistic objects. Until the
Industrial Revolution, charcoal was the primary and preferred fuel for
metalworking. Vast forests were cleared in Europe and then America to feed
furnaces and forges. Colliers made charcoal by arranging wood in large piles
and covering with soil or sod, leaving some holes at the bottom for
combustion air and a chimney in the middle for the gasses to escape. These
piles or clamps were then lit from the top and the burn controlled until the
wood became charcoal. This was dirty and dangerous work. The pile had to be
jumped during the burn to compact the coals and if the collier broke through
the soil covering, he also became charcoal. Back in the Ô50s, when I was
coming along and outdoor cooking was getting popular, there was an old man up
the road from us, who still made hickory charcoal the old-time way and sold
it in burlap bags. Charcoal clamps are now things of the past in the United
States and most of Europe but can still be found, contributing significant
amounts of greenhouse gasses, in many developing areas around the world. Though the
best charcoal for cooking is made from hardwoods such as hickory, cherry, oak
or mesquite, it can also be made from practically any organic matter:
Agricultural waste, bones, coconut shells, bagasse (sugar cane stalks), waste
wood or logs and even the occasional dead cat, though they tend to be
somewhat difficult to relight. Each type of charcoal has specific uses:
Amazonian natives created rich, productive soil (terra preta
do ’ndio or Indian black earth) by charring
agricultural waste and household refuse in trenches; Charcoal can be powdered
and used as a dietary supplement for digestive ailments; Activated charcoal
is used to absorb and remove ingested toxins; Ground charcoal is mixed with
sulfur and potassium nitrate (saltpeter) to
make gunpowder [Historical note: Early settlers in Virginia were required by
law to save urine to be shipped back to England for making gunpowder]; Amateur and professional pyrologists
use grapevine and willow charcoals for sparkling displays; Blacksmiths and
steelmakers prefer charcoal over coal or coke because it burns hotter, is low
in sulfur and is a good source for carbon in making steel; and
less-than-perfect moonshine can be run through an activated charcoal filter
to remove impurities, then stored in glass jars filled with under-cooked
charcoal to mellow and polish (donÕt ask). Good charcoal is
hard to find but easy to make at home. There are two basic methods for making it: direct and indirect. The direct method uses heat from the incomplete combustion
of the organic matter that is being charred. The rate of combustion is
controlled by regulating the amount of oxygen allowed into the burn and is
stopped by excluding oxygen before the charcoal itself begins to burn. This
is the ages-old method used by colliers to make charcoal in a pit, pile or
clamp, or more recently in metal or masonry chambers (kilns). The easiest way to
make charcoal at home is simply to burn wood down to coals and then to
exclude oxygen by covering with soil, or by placing the hot coals into an
airtight container until cool. When camping, I will collect good hot hardwood
coals from the campfire and put them in my smoker with the dampers closed
until they cool. Larger quantities can be made in a 55-gallon drum using the
Òtop down burnÓ method. [Note: Whether burning wood in a campfire, wood
stove, fireplace or masonry heater, the top-down
fire building technique is far superior to the traditional bottom-lit method
in that it is easier, more reliable and cleaner-burning. It enables more
complete combustion of the gases, resulting in less smoke, less wasted heat
energy, and faster, hotter burns. If regulated properly, the burn zone
advances slowly down through the wood using the available oxygen and thus
preventing the coals above from burning to ash.] Remove the top of the
drum and knock a few holes in the bottom for air, fill with split wood up to
three inches thick, top with kindling and light with newspaper or hot coals.
Once the fire is going good, replace the top loosely (a chimney with a damper is helpful
here) and let it burn until there is no more smoke, only clear shimmering
waves of heat. Cover the bottom holes with dirt to stop the burn, tighten the
top or close the damper and allow the drum and contents to cool several hours
or overnight to prevent re-ignition. The indirect method uses an
external heat source to "cook" organic matter contained in a
closed, but vented chamber (retort). This is usually carried out in a metal
or masonry chamber (furnace). The indirect method results in a higher yield
of high quality charcoal with less smoke and pollutants and requires less
skill and attention than direct burns. When I got serious about barbecue and needed
good, clean charcoal, I developed a procedure to make my own using a 30-gallon
drum as the retort and a 55-gallon drum for a furnace. This arrangement is
environmentally sound because all of the volatiles and pollutants are
directed into the fire and burned, providing additional heat to drive the
reaction. Alternatively, they may be captured and separated for other uses.
In more permanent configurations, waste heat may also be recovered in the
form of hot air or water with a heat exchanger or water jacket. The basic procedure
is quite simple: Drill five or six 3/8Ó holes in the bottom of a 30-gallon
drum (retort, small drum). Larger or smaller drums may be used for the
retort, but the larger the drum, the lower is the surface to volume ratio and
the longer it takes to burn, requiring much more energy. The relationship is
not linear so a 30-gallon drum is optimum and a 55-gallon drum is the
practical maximum. Cut a hole about 8Ó high by 12Ó wide in the bottom side of
the 55-gallon drum (furnace, large drum) for stoking the fire – save
the cutout for controlling airflow during the burn. Optional – attach a
three foot section of 4Ó stovepipe with damper to the furnace lid. Prepare
the wood so that billets are less than four inches thick – length is
not important as long as the billets can be packed into the smaller drum efficiently.
Pack the small drum with wood and secure the top (it is helpful to leave the
lid off or cracked on the smaller drum during the first third of the burn
while white water vapor is being released). Place the retort on three
firebricks laid on edge in the larger drum. Place the lid on the furnace and
open the damper – or leave the lid askew or slightly raised if you do
not use a chimney. Lay a fire under the retort and light it – I also
slip pieces of wood between the two drums initially. As the wood heats in the
retort, the smoke will be white from water vapor, then mostly clear as the
wood starts outgassing. If everything is right, combustible gasses will be
forced out under pressure into the fire. When it really gets going it sounds
like a jet engine. When outgassing stops and no flames are coming out of the
holes in the bottom of the retort, the burn is complete. If the top fits
tightly, the retort can just be left in place to cool – not enough air
will enter the bottom holes to ignite the charcoal. Alternatively, the retort
may be removed and placed on dirt to block the holes. When cool, dump the
charcoal into a wheelbarrow or whatever. It should be uniformly black with no
brown centers and should tinkle loudly when handled. If you have any brown
centers save them for polishing moonshine.
Timing is
important. Plan to start your burn on the hottest, muggiest day of the year
with a comfort index of at least 105 and air quality just above the minimum to
sustain life. These conditions won't affect the charcoal process at all but
will ensure that the experience is memorable. Note: Since I initially
published my web pages on ÒHow to Make Charcoal at HomeÓ back in 1998, they
have become cult classics steadily attracting ten times as many hits as any
of my other writings. Visitors come from all around the world, mostly from
the United States but also many from China, Asia, Africa, Russia and South
America. There are now large numbers of web pages, including university
studies, describing systems suspiciously similar to my original work, but no
credits. I went on to design a system based on 55-gallon drums and I
fabricated interchangeable steel bases and lids with detachable legs, gas
burners, and provisions for gas recovery, all made from readily available
materials. The invention was aimed at developing countries where there was a
need for efficient and portable charcoal production equipment that could be
used in the field. I seriously considered patenting and marketing the system
in South America, Asia and Africa, but decided that I did not want to spend
the rest of my life defending patents for a process as basic as charcoal
making. Charcoal,
as used to make barbecue, is primarily a source of consistent heat.
Therefore, if you purchase commercial charcoal, you are really buying BTUs
(British Thermal Units), a measure of heat content determined by the
percentage of fixed carbon. Natural briquettes and lump charcoals contain
significantly more BTUs per pound, burn considerably longer and produce much
less ash than the commonly available and cheaper ÒformulatedÓ briquettes,
which usually contain non-organic fillers. There is also a wide variation in
the quality of natural lump. Some popular, readily available brands are not
cooked enough, have a relatively low carbon density (heat index) and retain
enough volatile compounds to look like roman candles while being lit in a
chimney. If you canÕt make your own, at least buy a good quality charcoal.
After much research, we have decided to use and sell the ÒWicked GoodÓ brand
of natural charcoal. Popular on the competition circuit, Wicked Good is made
with a high quality blend of five South American hardwoods selected for long
burn times, high BTUs per pound and low ash content. All of the wood is grown
on plantations and does not contribute (further) to rain forest destruction.
Their kilns are state-of-the-art: Pollutants normally associated with
charcoal production are captured and processed rather than being allowed to
escape into the environment. The producers also take charcoal-making one step
beyond and remove most of the remaining volatiles, thus minimizing sparking,
a common and aggravating problem with some natural charcoals. Independent
tests indicate that Wicked Good lump charcoal burns almost twice as long as
the most popular manufactured briquettes, producing about 40% more heat and
leaving only 10% as much ash. Wicked Good all-natural briquettes stack up
even better – proving, once again, that it Òalways pays to go first
class.Ó So stop by Something Different for some wicked good charcoal, wicked
good barbecue and wicked good company. See also: http://www.nakedwhiz.com – Independent evaluation of
charcoals (c) Dan Gill - Published
in Pleasant Living November – December '12
Something Different Country Store and Deli More Blurbs from a Country Store
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