Slow Food Meet Slow Cook (a.k.a. the Hay Box)
by Warren McLaren, Sydney on 01.16.08
The other day John was ruminating on the energy efficiencies of slow cooking using ‘crock pots.’ My memory was jogged. I once set my students at a design college the assignment of designing and making a working prototype product that would reduce cooking energy by at least a measurable 25%. “You expect us to design a totally new type of stove in three weeks?” they cried. “Impossible!” Only it wasn’t.
With a little positive encouragement, discussions on heat transfer, insulation and a visit to a materials reuse centre, the students eventually twigged that they didn’t need to become instant engineers to achieve the requested result. As I recall, nearly all the teams passed, and most exceeded the 25% efficiency requirement. Many of their designs were variation of the venerable hay box, yet conjured direct from their own imaginations, without having seen such a device.
A ‘hay box’ is simply a sturdy container larger than its companion cooking vessel. It is lined with an insulative material that traps a lot of air (like hay or straw). Once the cook pot is placed inside an insulated lid is closed.
The heat contained in the food, especially water dense meals, continues to cook the food because the insulation reduces the ability of the contained heat to escape.
Yes, there is a time penalty, but a very significant energy efficiency gain. Plus your stove/oven is freed up for other pots and pans, and you can't burn meals that are slow cooked!
In its simplest form the idea is the ages old teapot cosy. A modern form for backpackers is the Optimus Terra cookset, (pictured right) which includes a close fitting nylon/neoprene warp for the camp pots. (Jetboil and AntiGravityGear do similar things)
A commenter (’kd’) over at Instructables, where they show you how to make your own hay box (pictured left and mid) reckons he/she uses one tenth of energy used to cook a meal by the related method of adding grains and boiling water to a large thermos flask.
You can get more info on hay boxes at Wikipedia, Mother Earth News and Lost Valley.
Hayboxing is fantastic. I volunteer for a camping organisation that takes kids camping and among other things cooks on open fires using army surplus (mainly korean war and ww2 surplus) cooking gear. We always have a haybox.
Most commonly we use it for keeping water warm overnight. We bring water up to the boil last thing in the evening after supper and then put two 6 gallon dixies of the stuff in the haybox. It is still around 50-60 ˚C in the morning so bringing it back to the boil is a lot quicker. we also premake porridge, bringing it up to the boil at night and letting it cook through slowly in the haybox overnight. It is also possible to let rice or other things finish up cooking in there or just useful as a resting place for hot food when things don't come together all at the same time (a common occurrence when 25 people aged 6 and a half to 80 are cooking for 100)
Why not go all the way and use a solar cooker? If any students had come up with this one, I hope they received extra credit for saving 100% energy consumption.
Solar cookers can be constructed in a variety of ways, two of which I am familiar with are (1) painting an old cabinet or box flat black (preferably metal, though wood works, too) and (2) using reclaimed double-pane glass on 2-4 sides (depending on location / weather), and insulating the bottom and north-facing sides, painting both flat black. The latter design works best with a lining of bricks painted flat black on the non-glass sides and the bottom 6-8 inches of the glass sides.
Most of either design can be made using mostly or all reclaimed materials. The solar cookers need to seal tightly to maximize efficiency, and you need to use high-temperature flat black paint--the kind used by non-environmentally-conscious folks to repaint their gas grills.
Cooking times can vary widely, depending on location, weather and type of food, so there is some experimentation involved.
Cheers,
Alan
I don't know about the MacBook, but THIS is a real energy-saver.
You don't actually need to buy a haybox cooker - you can simply make one. Box big enough for your pot + hay or blankets.
A bed also works really well - that\s what folks used to do in 'war time' - I was told, when I prepared a course for a banquet in a hay box cooker.
Actually - I didn't so much use a hay box cooker as a mountain of hay. Insulation is insulation and the mound of hay orked great.
It's a no-brainer.
http://www.culiblog.org/2006/06/here-as-the-centre-of-the-world-in-terms-of-food/
When i cook vegetables I just cover them, bring them to boil, turn off the heat and leave them till everything else is done. No hay required.
How does one bring water to a boil, then turn off the heat?(knocking on forehead)
... I've built a simple solar oven..and i'm working on a solar skillet...using USED red bricks and USED mirrors, and a USED non-plastic handled skillet....i know that i have to be careful using mirrors. Will it work? i'm hoping to be able to make solar cooked tortillas w/ the solar skillet.
I always try to use USED stuff. It is way more GREEN. My buddy and i were even talking about glue. wondering if tree sap would work, on ALL of the silver lined chip bags, available on the sidewalk as LITTER!!
We made the solar oven w/ stuff we already had. BUT, it was still manufactured & bought by me! aluminum Foil, glue aarrgghh
So the next solar cooker we build will be out of those chip bags, and anything we find in dumpsters, sidewalks, etc...WITHIN WALKING DISTANCE from our place!