[Stoves] Charcoal burning in stoves

Sat Dec 30 15:40:05 CST 2017

Greetings, Paul and Neil and Stoves List,
Two hours ago, I finished up an outdoor cooking session, making a
batch of 32 Naan (or 36?) and boiling a dozen fresh eggs.  I did use
some damp charcoal in the very bottom (of my nine inch TLUD) around
the edges of the cast iron grate.  Then I loaded the stove, with
thicker pieces (up to 1.5" dia rounds) in the bottom half, followed by
some finer pencil sized wood, then an inch or so of charcoal fines
soaked in old cooking oil, and then a couple inches of sliced
cardstock and copy paper slices .  A squirt of alcohol, a Mayan match,
and it was lit.  This stove doesn't emit smoke, perhaps because the
paper slices and small charcoal pieces glow red and ignite the smoke
created by the wood underneath.
This stove has evolved a bit over the years.  At first, I was using
ten inch worn-out carbide saw blades as a grate, but now have added a
small cast iron frying pan (handle sawed off) with some holes.  Photos
are shown below.  The steel lid (made from part of a 55 gallon barrel
top) is held in place (tightly) by a steel oil drain pan filled with a
mixture of plaster, pearlite, and crushed glass.  Two large U-Bolts
were cast into the plaster.  This mix has held up well, probably
because of the steel pan protecting it from the flame.  (I have cast
this mix into several old aluminum skillets as covers for my smaller
stoves.)  Originally, a grapefruit juice can was cast into the mix as
a riser, but it burnt out long ago.  Now, I just put the two bricks on
top of the plaster, and then the thing the pot sits on (from an old
gas stove), and set the pans or the wok on top.
The large Lodge Cast Iron Wok needs lots of power.  When I first built
this stove almost five years ago, I calculated the output to be about
7000 Watts, but now with the smaller number of holes in the grate, and
the use of a sacrificial liner (old stove pipe), it is probably less.
Still enough to partially burn some of the Naan, though, even when
making four at a time in 60° F (15°C) winter weather here in the
sub-tropics of South Texas.
The last photo shows the charcoal that I dumped out of the stove, and
extinguished with water.  Later, I will wash this charcoal, dry it,
and brush over a screen of hardware cloth (1/8" mesh).  Then it will
go into a charcoal grinder to reduce it to 3/4" and less, and then
screened again.  What falls through the screen will be added to the
compost piles and turned with a front-end loader, and will be used in
the garden.  The 3/4 minus will be stored as engine grade charcoal.
You may remember one of our first YouTube videos where we were making
Pita Bread on a Champion sized TLUD.  We now prefer Naan (made with
plain yogurt) and use them as pizza crusts, crackers, bread, cookies,
and snacks.  Getting the Pitas to puff up is quite an Art!, so we
settle for lots of Naan instead.
The 12 eggs will be made into a platter of Deviled Eggs for New Year's day.
Oh, my latest BBQ is actually a home-made rip-off of a Whitlox Wood
Fired forge using forced air from a 12 volt air mattress inflater
controlled via a Pulse Width Modulator (PWM) speed control.  I first
use a small TLUD for some cooking task, and then dump the glowing char
right into the forge, set the blower power at about 2 watts, and BBQ
is going strong.  The last photo shows some more Naan being made on
the forge using TLUD char.  A small shovel helps remove the char from
the forge and place it into the water-filled pan so a small amount of
char is recovered.
For steaks, the blower is adjusted to the 3 watt level.  (Power meter
and 12 volt battery.)  Sometimes, some fresh Mesquite or Oak pieces
are added to the char to get some of those delicious polycyclic
aromatic hydrocarbons (PAHs) as flavor.

On Sat, Dec 30, 2017 at 9:35 AM, Paul Anderson <psanders at ilstu.edu> wrote:
> Dear Neil,
>
> That is a marvelous report on practical BBQ cooking with charcoal fines!!!!
> I look forward to the photos.  And to any reports from other people who
> might replicate your rather distinctive charcoal BBQ cooking method.  I will
> probably do some experiments that relate to your reported experiences, but
> in the context of alternative TLUD stove structures.   THANKS!!
>
> You remind me of Paul van der Sluis, the Dutchman who did the "pyroneer"
> work that became the Philips FA gasifier stove.   He too is an avid and
> frequent cooker.   And also of Ray Menke in Texas where he cooks with TLUDs
> for mnay years.   The three of you have a shared situation:  relavtively
> mild climate that lets you cook outdoors for many many months of the year.
> (Right now in Illinois there are 15 cm (6 inches) of snow on my backyard.
> Plus, I am not handy as a cook.)
>
> To avoid the initial smoke, I recommend seeking an alternative to paper.
> Maybe some charcoal lighter fluid or alcohol on a dense pad of steel-wool or
> on some of the same charcoal fines but placed below the grate so that the
> fan can do its job.   If you try something, please let us know.
>
> Paul
>
> Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
> Email:  psanders at ilstu.edu
> Skype:   paultlud    Phone: +1-309-452-7072
> Website:  www.drtlud.com
>
> On 12/30/2017 6:22 AM, neiltm at uwclub.net wrote:
>>
>> On 29 Dec 2017 at 9:52, Paul Anderson wrote:
>>
>>> Neil,
>>>
>>> On 12/28/2017 4:54 PM, neiltm at uwclub.net wrote:
>>>>
>>>> With very fine char such as the TLUDs produce, I re-use the mesh
>>>> scavenged from other peoples discarded disposable BBQ trays doubled up
>>>> across the grate to retain the fines.  Lit with a couple of sheets of
>>>> newspaper, and an old computer fan to augment the draft, we are cooking
>>>> in under a minute of striking the match.
>>>
>>> I understand the grate and the char placement.   What are the walls like
>>> in this charcoal burner?
>>>
>>> What is the thickness of the char layer (because some air needs to be
>>> able to pass upward through the char, riight?
>>>
>> Yes. I've never measured, which would be difficult given very varied
>> sized pieces of char, but little more than is needed to cover the grate
>> generously, so say an inch/ inch and a half, with larger pieces poking up
>> above that.  My reason for coming up with the fan in the first place was
>> experiencing too much ND draft restriction with the fine char, but mostly
>> it is needed only for quick starting, adding fuel, and occasionally as a
>> boost, more so if I am starting with a thicker layer, and sometimes to
>> get the last gasp out of an exhausting layer more quickly.
>>
>>> Is the ignition paper under the grate?
>>>
>> Yes, that's right.  There is a small sliding door to regulate the draft
>> which I made a sheet metal 'funnel' to (push) fit, with the computer fan
>> at the other end, running off any old 12v car battery.  This ensures a
>> rapid and complete combustion of the paper, and immediate and even
>> ignition of the char.  For about 30 seconds the billowing white smoke
>> looks as if I'm announcing the election of a new Pope before all rapidly
>> settles down to a smokeless burn.
>>
>>> How long wiill it burn (in relation to thickness of layer?   or to
>>> weight?   or what else?)
>>>
>> I've not done any weight measurements, but I find it hard to imagine a
>> more fuel efficient BBQ.
>>
>> I usually start with enough fuel for a half hour cook before needing to
>> add more fuel.  Because it is only a fairly small BBQ, (14inch diameter
>> griddle), I usually cook in batches, adding more char each time.  If I'm
>> cooking chicken joints from raw I aim for about 40 minutes which is easy
>> to achieve on one loading. There seems little point in trying to control
>> a thicker layer for a longer time than the food needs to cook, so each
>> batch of food gets its own fresh layer of fuel.
>>
>> This is all made easier by the excellent control I have over the fire,
>> whether by entirely regulating the ND with the sliding 'door', or if
>> needed, occasionally bringing the fire up with the fan, usually only in
>> short bursts or for getting the flames to quickly break through a new
>> layer of char.  In addition to these options, there are 4 heights at
>> which the grill can be held above the fire.  Mostly I aim not to have
>> flames licking around the food, and if things get too lively are brought
>> back under control quickly by closing the draft off.  The heat is greater
>> at the centre and towards the back, so food is also moved around as
>> required.
>>
>>> Any other comments that might be useful???
>>>
>> The fine char in the mix definitely helps with rapid lighting and
>> establishment of a cooking fire compared with large lumpwood only.
>>
>>> The issue is "combustion of charcoal that is NOT lump and is somewhat
>>> "fine" but not powder(?).
>>>
>> Correct.  I use a fine riddle to remove the ash and char below the mesh
>> size which is approx 2.5mm sq hole size.  Obviously most of the char is
>> well above that sort of size, being the sort of mix you would expect from
>> a TLUD, rocket stove or open fire.  It's only the open fire char where I
>> ever need to break up some of the larger lumps.
>>
>> I can do some measurements and photos when the warmer weather comes if it
>> might be of any interest.  I've had this BBQ for 25 years now, so its a
>> familiar tool that I am nicely attuned to, and the design persists,
>> although as I said I couldn't find it on ebay.com, only .co.uk.
>>
>> Best wishes,   Neil Taylor
>>
>>> Paul
>>>
>>> Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
>>> Email:  psanders at ilstu.edu
>>> Skype:   paultlud    Phone: +1-309-452-7072
>>> Website:  www.drtlud.com
>>>
>>>
>>>
>

-- 
Ray  Menke
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