from: jan-ellen jones harriman, internet:janellen@usa.nai.net
date: thu, 25 jul 1996
subject: article on cooking pots?
as a novice solar cook learning to put the pieces together to really =
make this work, i would appreciate an article on cooking pot types.
something thorough on the comparative efficiency of enamel vs iron vs =
glass. is speckled black enamel substantially less effective than plain =
black. is a shiny finish better or worse than matte. =20
in my *very* limited experience i have found that an amber pyrex dish =
works well but their 'cranberry' dish doesn't seem to work very well at =
all. (is it absorbing the wrong wave lengths or are other variables =
such as the use of a cooking bag instead of a glass dome in my panel =
cooker the cause)
i would be willing to author this if people could send me accounts of =
their experience and/or any data they might have on this topic.
thanks for all the great info that has gotten me started. =20
je
***
from: marge wood, internet:woodm@nicanor.acu.edu
date: thu, 25 jul 1996
subject: re: article on cooking pots?
i think the main things are to have ingredients as close to room temp as
possible, and if possible, preheat pots, and have tight closure of glass
and box, and use a glass lid on pot so you don't have to open the cooker
to check on the food. also, shift the cooker every hour or so in order
to point it right at the sun. it makes a lot of difference, like 50 degrees.
marge wood,
***
from: nancy greener, internet:smiths@azstarnet.com
date: wed, 31 jul 1996
subject: re: article on cooking pots?
on wed, 24 jul 1996 jan-ellen jones harriman wrote:
> as a novice solar cook learning to put the pieces together to really
> make this work, i would appreciate an article on cooking pot types.
for cooking pots i love the "radabaugh jars". these are simply
wide-mouthed glass jars painted black as described by joseph radabaugh
in his book, _heaven's flame_. i converted two laura scudder's peanut
butter jars and a wide-mouthed mayo jar for this purpose. radabaugh
suggests placing a strip of masking tape down the side prior to
painting. when the tape is removed, you'll have a clear strip which
will allow you to observe the cooking process (i used wide scotch tape
which worked fine).
radabaugh suggests painting these with a mixture of elmer's glue and
black tempera paint, but doesn't give proportions. i didn't feel like
experimenting, so used flat-black spray paint purchased in a hardware
store. don't buy the expensive high-temperature paint (rated for 600
degrees fahrenheit), it isn't necessary for solar cooking. before
painting, the jars and lids were thoroughly cleaned, allowed to air-dry
and then wiped with rubbing alcohol to ensure a grease-free surface.
after painting, i allowed everything to out-gas in the sun for a couple
of days, long after the paint smell was no longer detectable.
radabaugh suggests poking a small hole in the jar lids to allow the
release of steam pressure. instead of this, i just screw the lids on
loosely (just the top thread or two of the jar) which works fine. by
keeping the lid intact, the same vessel can be used soak (beans, hominy,
etc.), cook and refrigerate the food. if necessary, the same jars can
still be used to store dry beans, grains, etc. i've never experienced
any boil-over using my box cooker but, to be safe, you can place your
jars on a baking sheet or pan to catch any spills.
another cooking vessel i like is a dark brown ceramic cheese crock which
is 4 1/4" high and 5 1/4" in diameter. this cooks brown rice and beans
in little more time than it takes in the jars. as sbci has stated, the
thick walls (~1/4" in this case) will act as a heat sink, so the food
will continue to cook a while longer after removing it from the oven.
other advantages to using jars or crocks are that you can cook more items
at a time since they have a smaller footprint than regular pots, and they
won't affect the flavor of acidic items like tomato sauce or fruits.
if you don't want to paint the jars, you can use clear ones, but the
food will take longer to cook (if you can get dark glass jars, you're in
luck). radabaugh also suggests wide-based pickle jars but cautions
against using gallon jars since the heat differential from top to bottom
will cause them to break.
for making tamales or other steamed foods, i've used one of those large
black speckled enamel steaming pots sold in many supermarkets for
spaghetti, canning, etc. this is too tall for my box cooker so i
removed the steamer insert (adds about two inches) and placed one of
those stainless-steel collapsible steamers inside. i later acquired a
second-hand aluminum steamer pot which i painted flat black. when using
this, i noticed the sound of simmering water when removing it from the
cooker. i don't recall this ever happening with the enamel steamer
which got the water hot, but not simmering. this could be due to:
1. the fact that aluminum is a better conductor of heat than
enamel-covered metal.
2. different cooker temperature (usually somewhere in the range of
225-250 degrees f or 107-121 degrees c)
3. the flat-black surface absorbs more solar radiation than the
shiny-black enamel.
4. the need to believe i'd made an improvement ;)
your own results will likely vary with the kind of cooker you're using.
for roasting potatoes, eggplant, etc, one of those black speckled enamel
roasters has worked very well. for casserole-type things like lasagna
i've used a clear glass baking dish covered with a black aluminium
baking sheet to improve heat conductivity.
there is no need to purchase expensive glass cookware. the
aforementioned items have served me well for years.
bon appetit,
nancy
from: harry bernstein, internet:h.bernstein@uws.edu.au
date: mon, 12 aug 1996
subject: ambient temperature
here in sydney, australia it is late winter. day temperatures reach a
maximum of about 20 celcius or 68 fahrenheit.
i am experimenting with solar ovens and can heat water but not to boiling. i
enjoyed hard boiled eggs yesterday but could not succesfully cook potatoes.
should i be able to boil water when the hottest part of the day is 68
degreess fahrenheit ?
harry bernstein
faculty of commerce
university of western sydney, nepean
p.o. box 10, kingswood nsw 2747, australia
***
from: marge wood, internet:woodm@nicanor.acu.edu
date: mon, 12 aug 1996
subject: re: ambient temperature
yes. i have a photo of a pot of potatoes boiling on the shortest day of
the year.
marge
***
from: steve r. cook, internet:stevec@utep.edu
date: mon, 12 aug 1996
subject: re: ambient temperature
i think that sun angle may have alot to do with your struggle to cook
potatoes. marge, you can easily compensate for low sun angles with your
cooker, right? in a solar box cooker at least, you'll find a longer shadow
cast by the front wall of the box and just less energy density in winter
than in summer.
steve
steve r. cook, program coordinator stevec@utep.edu
the energy center, university of texas at el paso
p.o. box 645 el paso, tx 79968 (915)747-6646 fax:(915)747-5317
***
from: marge wood, internet:woodm@nicanor.acu.edu
date: tue, 13 aug 1996
subject: re: ambient temperature
point your cooker at the sun; get the sun at right angles to the pot. it
helps maybe 50 degrees fahrenheit.
marge, who has cooked roasts on new years' eve and potatoes in the snow.....
***
from: internet:info@solarcookers.org, internet:info@solarcookers.org
date: tue, 13 aug 1996
subject: solar cooking in nsw
dr. bernstein asked about solar cooking on
a mild winter day in new south wales. the
ambient temperature is a less crucial factor with
most solar cookers than the angle and intensity of
the sun. the sun is fairly low in nsw in august and
may not be sufficient to power your cooker. this
problem will be even worse if the sky is very hazy or
foggy. i have read of people doing serious solar
cooking with low sun angles, but they usually have
very well insulated box cookers and/or extra
reflectors.
by september or october you should be able to boil
water on a sunny day if your cooker is an adequate
cooker. if you can't, it sounds like there is
something wrong with the cooker.
sincerely,
kevin coyle
resources coordinator
solar cookers international
***
from: internet:jonesse@plasma.byu.edu, internet:jonesse@plasma.byu.edu
date: tue, 13 aug 1996
subject: message from internet
harry bernstein asks if he can expect to boil water during the australian
winter (air about 68 f).
no problem.
last winter here in provo, i boiled water easily -- in about 1/2 hour for
a small quantity of water, using the solar funnel cooker i had developed.
i wanted to do this because another physics professor here did not believe
it could be done. so i just set up and did it. the sun in january was only
about 30 degrees above the southern horizon, so i tipped the funnel on its
side. used a plastic 2-liter pop bottle for the "hood" in that test,
and an aluminum container painted black. prof. mason was pleasantly surprised
-- as was i, to tell the truth.
later, i broke a jam jar which i had painted black and nested inside
another, larger and clear, jar -- and set inside the solar funnel. the pressure
with water boiling was evidently too great for the small jam jar, closed
tightly. i agree with barbara -- canning jars with normal canning lids
are best, and safer. that's what i now use (painted black on the outside).
the hood is usually an oven-safe (reynolds) plastic bag, although i sometimes
use another (clear) jar -- which works better than the bag.
--steven jones
byu physics dept.
p.s. the outside temperature during the tests was just above freezing.
from: larry m blakely, internet:lblakely@telis.org
date: sat, 13 jul 1996
subject: polenta: easy and energy efficient
dear solar cookers,
i've really been astounded by the performance of my homemade cardboard
cooker, made from plans on the web site. i tell everyone about it. i
felt inspired today to send off the following note to sunset magazine;
hope they will use it or maybe look into solar cooking. it would be
great if they would do a story on it.
best wishes,
larry
lblakely@telis.org
polenta: easy and energy efficient
i first made polenta after being inspired by reading your recipe for
polenta lasagna in the feb. 9196 issue. super!
after finding out what it is and how to make it from a dusty copy of the
"mama mia italian cookbook" in our library, i spent 45 minutes constantly
stirring the corn meal as it cooked on our electric range (mama mia said
it would only take 30 minutes - well we are at 4500' here on the sage
sparrow ranch). a lot of energy went into it - mine and southern
california edison's!
i have since learned from my daughter in the big city that you can get
precooked polenta - canned or dry powder. however, the energy miser in
me is only too well aware that the manufacturers use lots of energy in
the process of making it. can you make it without using so many calories
or btus?
yes - here's how:
make (http://solarcooking.org/plans.htm) or buy (explore the same
web site) a solar cooker. it's really easy and cheap to make one; i made=
mine from 2 cardboard boxes, aluminum foil, a turkey-sized oven bag,
diluted carpenter's glue, and some coat hanger wire.
for a noon-time lasagna, aim your solar cooker at the sun at about 9 am.
back in the kitchen, stir 1/2 cup corn meal into 2 3/4 cups hot water in
a dark pot. (i use an old aluminum 1 qt covered pot that i spray painted
black, using a non-toxic "when dry" high temperature paint.) put the pot
in the cooker and do something else for 2 hours, like getting other
things ready for the lasagna. at 11 am your polenta will be done - you
can leave it in longer as it won't overcook.
instead of lasagna you can make a tasty luncheon dish by stirring in 2/3
cups grated cheddar cheese and some dried herbs at around 11:15, removing
it from the oven (use pot holders!) at quarter of noon. let it cool and
enjoy!
now, if all the mama mias and their kindred spirits around the world
would do this, think how much drudgery and btus would be saved. it's
mind boggling!
larry blakely
route 1, 415 sierra grande
bishop, ca 93514
619-872-1890
lblakely@telis.org
***
from: barbara kerr, internet:kerrcole@frontiernet.net
date: mit, 17 jul 1996
subject: re: polenta: easy and energy efficient
i tried this and it was great!
hello
i am a technology teacher in mccreary manitoba canada and i am experimenting in teaching solar cooking. we are starting with a solor hot dog cooker using the focused rays of the sun. could you tell me exactly what are the dangers to the students eyes and some ways to avoid them. any help would be appreciated.
thanks
mike annetts
------------
reply 4/26/97
hello mike,
the danger from foil is overexposure to the retina which in a mild form causes a transient blank spot, but which in excess can cause changes that are irreversible ...clearly a serious consideration. however, almost all of our energy technologies have dangers. we just learn how to deal with them safely.
it is not difficult to work with solar devices safely. it is mostly a matter of understanding that there is a potential danger and that it can and should be avoided.
we know never to look directly at the sun except perhaps just as it is rising or setting. this is widely taught in solar eclipse publicity.
foil reflections can be 85% or more of full sunlight. single reflections from foil are uncomfortable and one tends to squint and move away. multiple reflections, which are essential for cooking, are of most concern. pain is a guide on the hand, etc., as the concentrated solar heat can be felt and in the bigger devices, such as some parabolic cookers, one can get skin blisters. however, pain is not a guide to eye damage. retinal damage occurs without pain.
a good guide is that if one needs to squint from brightness, one should either move away or put on a full-spectrum sunglasses. it is not "macho" to be able to stand or place the face in a bright spot ... it is dumb. and shows a lack of understanding of the power of the energy we are dealing with here.
when working with foil, as at a table gluing, etc., the person's back should be toward the light so the reflection bounces away.
this makes an interesting introduction to solar energy for students: how light reflects and how we position ourselves relative to it. as well as how we put the food in the area of concentration of reflection in order to cook.
when using the sun to cook, any reflection you can see is wasted as far as cooking is concerned. it should be directed on the food. there is usually some spillage, so solar cookers are approached either from the sunny side, or in a away that minimizes exposure to the brightness.
i have been solar cooking since 1973 and have great eyesight. there does not need to be damage but the dangers need to be taught and respected.
i hope you and the class enjoy your exploration of solar cooking. you probably have this, but just in case you have missed some, i am sending our list of electronic solar connections.
cheers,
barbara kerr
from: john grout, jgrout@mail.cox.smu.edu
date: wed, 19 feb 1997
subject: why not hotter?
i have yet to build my first solar cooker and have a technical question
and a survey question:
technical question:
the oven builders that i have read about so far seem to feel
really good about reaching 350 degrees f. why not shoot for 500 or more
like an electric oven? if you increase the collection area that is
concentrated in the oven, the sun should provides enough energy shouldn't
it? what is driving the design decision to be satisfied with lower
temperatures? is it temperature regulation that is the problem (how to
cook at 350 with an oven that wants to reach 500) or something else?
survey question:
what is the record high temperture you have hit with your oven? briefly
describe it.
i'm trying to figure out what to build. sharing your expertise will
be most gratefully received. john (jgrout@mail.cox.smu.edu)
***
from: michael brugger, mbrugger@uga.cc.uga.edu
date: wed, 19 feb 1997,
subject: re: why not hotter?
john, if you are making a cooker out of cardboard, the combustion point of
paper (cardboard) is 451f. so 500f would cause a fire. the cooker i use gets
to 275f and does an adequate job cooking food. i hope this helps. cheers, mike
michael p. brugger pa-c
use it up, wear it out;
make it do, or do without.
winterville, georgia u.s.a.
** ask me about solar box cookers **
mbrugger@uga.cc.uga.edu
***
from: barbara kerr, kerrcole@frontiernet.net
date: wed, 19 feb 1997
subject: re: why not hotter?
some of us feel good about ovens in the 250 degree f to 300 degree
range because of the gentle, flavorful cooking they do.
as you get hotter, you have more problems with scorching and
charring. it depends on just what you want to do. for
staying right with it and perhaps doing a rotisserie, etc.
above 400 might not persent problems. but the lower temperature
ovens do meats delicately and the result is tenderizing...i
have roasted the neck of a 7 point elk in a solar box cooker
reaching below 300 and found it tenderized to the point of
normal beef...only slightly resistant to cutting...and very
flavorful. these lower temperatures also bake cakes and bread
taking about twice the time of the 400 degree ovens.
to each his own. let us know whatyou decide and how it
works out for you.
cheers,
barbara
***
from: goetz, michael.goetz@imt.unine.ch
date: fri, 21 feb 1997
subject: why not hotter?
a little bit of physics:
the heat loss of the oven is a function of the difference of temperature
between the inside and the air around. the bigger this difference, the more
heat is lost trough walls and front glass. the maximum temperature is given
by the equilibrium of the heat you constantly add (by sunlight) and the heat
you constantly loose (through the insulation). of course, this equilibrium
takes a while to reach, as your food has to be brought to this temperature
as well.
there are two ways to rise the maximum temperature:
1) add more heat to the system by focalising the sunlight (mirrors, lenses)
2) loose less heat by better insulation
the typical cookers not designed to get the highest temperature imaginable
(you can melt metals with a very big parabolic mirror!), but they are a
compromise between many factors like security (do not focalise the light too
much), cost (insulation), ease of utilisation (a strongly foculised mirror
has to be adjusted every minute or so), but still they do cook!
mitch
***
from: renewable news network, rnn@rnn.com
date: fri, 21 feb 1997
subject: re: why not hotter?
on tue, 18 feb 1997, john grout wrote:
> i have yet to build my first solar cooker and have a technical question
> and a survey question:
>
if everybody who'd done nothing, would stop
asking questions, and
try doing something instead, it would be a very quiet world.
> technical question:
>
> the oven builders that i have read about so far seem to feel
> really good about reaching 350 degrees f. why not shoot for 500 or more
> like an electric oven?
the answer to this question is that you have not reached 350 yet.
if you increase the collection area that is
> concentrated in the oven, the sun should provides enough energy shouldn't
> it?
yes - no
what is driving the design decision to be satisfied with lower
> temperatures?
who is satisified? who's driving?
is it temperature regulation that is the problem (how to
> cook at 350 with an oven that wants to reach 500) or something else?
>
its something else.
>
> survey question:
>
> what is the record high temperture you have hit with your oven? briefly
> describe it.
>
lets try a new catagory of handheld solar ovens. that would be an
interesting criteria. we could also start at 500 degrees
f. and go up from there. application: vaporizing stuff..
>
> i'm trying to figure out what to build. sharing your expertise will
> be most gratefully received. john (jgrout@mail.cox.smu.edu)
>
how about a collaoration.
yours truly,
ross donald
***
from: john grout, jgrout@mail.cox.smu.edu
date: fri, 21 feb 1997
subject: re: why not hotter?
a collaboration sounds great! it so great to find like-minded people on
the internet. it's such a warm nurturing place. thanks. john
jgrout@mail.cox.smu.edu
***
from: rdlux@aol.com
date: fri, 21 feb 1997
subject: re: why not hotter?
one of the reasons i prefer the slower cooking, lower temperatures found in
the cardboard or panel cookers is that it allows me to do my cooking while
i'm at work. with higher temps. food has to be "attended" so as not to burn.
lower temperatures besides producing (to my mind anyway) tastier food, gives
me more freedom. i'm not a slave to the stove.
michael bonke internet training
millrather str. 22
40591 duesseldorf
tel: 0211 97 79 023
fax: 0211 97 79 025
www: http://www.optimist.com
besuchen sie mich auf der cebit: halle 18, 1. og, stand b12 (global
entrepreneurs network - gen)!