Putting it all together

Let me try to summarize the various cooking methods I hope to use regularly in future. Almost all involve a solar cooker at some point.

I’ll begin with what started this whole journey for me: the solar box oven. Pretty much any slow cooker recipe will work for a box oven. The main constraint is consistent sunlight for a long enough period of time. Intermittent clouds can sometimes reduce the oven temps below safe levels. Also, if you are not home to re-orient/aim the oven every hour or two, then longer cooking times will be necessary.

The parabolic cooker does not require as much sun time as the box oven, but you need to be ready to cook when the sun is out. This works fine if you have sunlight an hour or so before the planned meal. One way to extend the cooking time is to use a heat-retention method (hay-box or thermal cooker) to keep the food hot until mealtime. You can find other sources of insulation if hay is not handy.
Note: you can always click on an image to see a clearer (sometimes larger) version.

Thermal cookers (wide mouth thermoses work) and hay-boxes are especially good for cooking stews, curries & soups; dishes with high liquid content. The parabolic cooker would bring the food up to a boil and then the boiling hot food would be transferred to a pre-heated container to cook further in your choice of heat-retention apparatus. This way the food stays hot even if mealtime is hours away. When cooking for 4-5 people I use a 4 qt. Zojirushi thermal cooker. For 1-2 people I will be using this Thermos Nissan 48 oz. Wide Mouth Stainless-Steel Bottle.

Another tool to help with limited sun time is to use a pressure cooker. Recipes abound for this cooking method and you can often have a main dish ready with less than an hour of parabolic cooking time.

The final method is arguably not cooking per se, but dehydrated food can often help in speeding up cooking when sunlight is limited. It doesn’t take nearly as long to reconstitute dehydrated potatoes or meat as it does to cook them in from their raw state. Of course dehydrated fruit, veggies, jerky & fruit leather can be eaten as snacks.

To bring it full circle to solar cooking, the trays of my electric dehydrator can be placed into my solar box oven with a few modifications (subject for another blog post). I will have to pick the types of food to match the amount of sunlight anticipated on a given day, but if the weather doesn’t cooperate I can always complete the dehydration in the electric dehydrator.

To recap:
*box oven: slow cooking & dehydrating
*parabolic cooker: re-heating, fry/sauté & bringing to boil to put into hay-box or thermal cooker
*thermal cooker: slow cooking soups, stews, curries
*pressure cooker: too many to list
*dehydrator: almost anything you can think of including fruit leather, jerky, fruit chips, cooked corn/potatoes/beans…

Pressure cookers: small ones to fit in a solar cooker

There are many sites about pressure cookers that explain the basics of how they work and why they conserve energy. For solar cooker users, the latter reason isn’t really critical, but it does help to have a pressure cooker that is dark colored to better absorb the sun’s energy. Most solar cookers also have limited space, so I looked for pressure cookers in the 3-4 qt. range.

There were not many that fit my requirements and I chose the Hawkins Futura line (3 litre version) primarily because Hawkins has many years of experience in building pressure cookers. I emailed them to confirm that the anodized aluminum Futura cooked at 15 psi and quickly received an affirmative reply. I had been advised that some pressure cookers (especially aluminum ones) only reached 10-12 psi. Spec sheets across the board rarely listed the psi rating.

A similarly priced option was the 2.8 L Halulite made by GSI Outdoors, the company famous for its lightweight camping gear.

This is probably also a safe option, but it might be a bit harder to find a replacement gasket in the future. Since GSI usually focuses on light weight gear, it’s no surprise that their pressure cooker at 2.75 lbs. weighs less than half of the similarly sized Futura at 6.2 lbs. I did not verify the psi spec, so you’ll want to do that if you’re interested in this one.

The additional thermal mass of the Futura would actually be a benefit with a parabolic solar cooker because it would more evenly distribute the intense energy usually generated. In fact, a standard 4 qt. stainless steel pressure cooker would probably work just fine on a 4-5 ft. parabolic cooker. However, if you intend to use the pressure cooker in a Parvati solar oven (a parabolic funnel), the thinner walled Halulite would probably be the better choice.

Hawkins has a unique design that requires a modified version of closing & opening the lid. You should read these instructions carefully. Browse their excellent website for more info on pressure cookers.