Neil,
Thank you for your very interesting comments about your experiences with
TLUD cooking.
You asked about people experimenting with cooking. There are so many
people, there are sure to be some who experiment. And some get lucky
and new methods and info occur. But for the most part, I think that
cooking remains the same, even from generation to generation.
To be innovative (and not just lucky) requires sufficient success to be
encouraging to continue innovating. Or some past experience (Wendelbo)
or advanced knowledge (Reed) or an introduction to something new
(Anderson and many others, including yourself) that triggers the desire
to keep experimenting until there is success.
But many people do not have the freedom (of time) and resources to make
the experiments over and over and over until something useful occurs.
If the food is not cooked, the consequences are bad enough to not want
to try again with something shown to not be working well.
That is why I disagree about “ask the cooks to design the stove that
they want.” Of course that can work, and we do want inputs from the
eventual customers / users of the stoves. But it is not reasonable to
expect some breakthrough with some group of cooks, when millions of
groups of cooks during thousands of years of human use of fire to
prepare food have still left so many people still cooking on 3-stone
fires today.
Example: If a layer of damp fuel in the bottom of TLUD stoves is
turning out to be noteworthy (and it is), why has it taken over 30 years
of TLUD existance to have that discovered? Maybe someone else did it
earlier, but the message never got circulated. And even now, the
distribution and discussion and (I hope) further experimentation by
others is still extremely limited. And WE are connected. At the
village level, small improvements might reach another village, but much
depends on contacts by the person(s) with the improvement and those who
might check it out and might adopt it. That means to cook in one house
meeting the cook in a house in a different village, not the village
leaders getting together with other village leaders who all know very
little about what the cook did to make the food they eat.
Maybe others will carry on this discussion on the Stoves Listserv. ( I
must continue my preparation for the ETHOS meeting where some stove
innovations might be shared, but very few of the innovations are from
the cooks.)
Paul
On 1/18/2017 5:44 AM, neiltm@uwclub.net wrote:
> Breakfast this morning marked a further improvement in the usefulness of
> the stratified batch loading, and a tentative conclusion that there is a
> useful general principle to be taken from this.
>
> This morning’s breakfast consisted of lightly frying smoked mackeral in
> butter, followed by putting on a kettle for coffee, followed by toast
> made over the char at the end of the burn with the concentrator disk and
> pot support removed. This has been one of our breakfast routines for
> years, and something the Reed woodgas campstove LE did well.
>
> It was freezing hard this morning and so the outside wood was not just
> wet, but frozen solid.
>
> I put a generous layer of just the frozen wood in the bottom, half
> wondering if I might be pushing it a bit for expecting it not to struggle
> with hitting that layer, albeit right at the bottom.
>
> After eating the fish, (indoors!), I came out to a half filled kettle
> boiling its head off, in contrast to it more usually needing a bit of
> extra wood to bring less water to the boil.
>
> When I took the kettle off, the flame was lovely. Mostly the char
> burning vigorously, but very noticeably augmented by the obviously still
> pyrolising bottom layer which was streaking the blue flame with red, but
> not smoking. (I’ll try and take a picture of this to share and get some
> timings). The combined combustion looked really nice and seemed obvious
> to me that the bottom layer was maintaining a much more vigorous fire
> than would have been the case with just the char burning off. Not only
> that, but it continued for some time after I had made the toast, which
> was really quick. So often the toast stage has been a bit of a last gasp
> barely doing the job and a bit rushed to get to it before it disappears,
> but not this morning. And this was all off one batch loading, no feeding
> at all. This was a far more useful fire than I would normally get from a
> batch loading in this stove.
>
> I wouldn’t want to try to claim that more heat was output from the stove
> with the wet wood layer, but clearly more *useful* (to me) heat was, and
> that’s my point, this simple technique is a great control over getting
> the fire you want when you want it. This is no longer merely a way to
> usefully burn wet found wood where ‘better’ dry fuel might be
> unavailable, it occurs to me that a bottom layer of deliberately soaked
> wood might, in simple TLUDs, prove advantageous for control where there
> is no naturally found damp wood.
>
> Instead of an unwanted flare up at the end of the burn as the chamber
> floor reflects heat back into the bottom fuel, this tendency is instead
> taken advantage of by modifying the fuel at the bottom, and optionally
> variably above it, to control the rate of combustion, potentially greatly
> extending it. For my cooking purposes this morning I probably did overdo
> the frozen wood layer in that the fire lasted longer than I wanted it,
> and in the process of waiting for pyrolysis to finish I lost some of the
> remaining char which was still much more than usually remains from that
> cooking routine, the toast stage usually pretty much consuming it.
>
> I have found that modifying the wood chunk size makes far less difference
> to the size of the flame than you might think. With chainsaw dust it has
> to get almost that small before it exercises enough control over the
> primary air to give a long moderate or simmer heat, but then the stove is
> useless once the batch is burned and cannot be revived. Ditto for mixed
> woodchip including a lot of fines. With large chunks the stove is
> easiest to keep going indefinitely by further feeding. I am using very
> large chunks of dried hardwood that was felled green only a few weeks ago
> and dried on top of our central heating boiler, but these do seemingly
> nothing to slow the rate of burn down. There is so much more control,
> and potentially really fine control over the heat by varying the moisture
> content in combination with stratifying to produce wanted change over
> time. There is a simplicity in this approach that might have the
> potential to further improve and refine the turn down/up control sought
> through variable air supplies in more sophisticated NDTLUDs?
>
> I guess it is one thing not to expect a biomass cook to naturally invent
> a TLUD, or any kind of improved stove necessarily, but to what extent do
> cooks commonly and naturally without necessarily thinking about it,
> intuitively as it were, modify how they make and tend a fire, select and
> prepare fuel to the extent that, just like me they may come up with all
> manner of refined ways to use simple stoves to get better control over
> the fire they want? I have never seen that Q discussed, and would be
> interested in thoughts and observations on the Q. If that potential
> proved to be a commonplace human attribute, then controlling the fuel in
> combination with good stove design surely ought to be able to achieve
> better results? Is there even a danger in not doing so that the cook is
> being de-skilled by being handed an LPG stove, or improved biomass
> cookstove with processed biomass fuel that aims at LPG levels of skill to
> operate? I don’t know the answers to these questions, but I’m hoping
> those working in the field who have observed fire making and using
> skills, especially with simple stoves, might enlighten me. Some and some
> I expect, human aptitudes being usually highly variable. My own laziness
> to prepare TLUD fuel has impelled experiments in ‘how large can the
> chunks be?’ for eg.
>
> Neil Taylor