July 23, 2012

DIY Solar Oven: Autoshade, Bucket & Cooling Rack Cooker

Hot enough out there for you yet? If you're here in the Central Valley like me, I suspect the answer is a resounding YES, followed by, "that's enough, thank you very much!" I actually don't mind the summer heat, but even I'm ready for a return to the low 90s.

When it comes to dinner preparation, the only reasonable response to a triple digit forecast like we've got today is to abandon indoor oven and stovetop cooking in favor of other options, such as: grilling (but then you have to stand out in the heat); sandwiches, salad or another meal that doesn't require heating up the house; going out to eat (but that requires money); or my favorite, solar cooking.

DIY autoshade & bucket solar cooker

When the sun is pumping out that much warmth and energy, why not harness it and use it to make dinner? Well, one reason why might be that you don't have a fancy solar cooker or you're not sure how to make one yourself. Good new is, it's easy! I put one together last summer using things that are probably already in your garage, kitchen or garden shed.

Solar cooker storage box

I call it the A-B-C solar cooker, because all you need for this contraption are the following:
  • Autoshade--air bubble or foam mylar
  • Bucket--black, five-gallon is best
  • Cooling rack--like the type used to cool cookies after baking

Oven bags are nice if you want to increase the temperature in the cooking dish, and a thermometer is handy if you want to know exactly how hot it is in there. Attach some velcro to the edges of the autoshade to make it easier to bend into shape if you want to get fancy. Otherwise pin it together with safety pins. You can see in the photo above that I've attached some basic string to each outside top corner. That's so I can secure it when there's a North wind to go along with our yucky heat. Finally, don't forget the sunglasses! You wouldn't look directly at this oven anymore than you would look directly at the sun.

To make the oven, just bend the autoshade into a funnel shape and rest it in the bucket, set the cooling rack at the base of the shade so that it rests on the rim of the bucket, and orient it to face the sun. Done!

Roasting pan on the rack, on the autoshade, in the bucket

Even when I cook from say 2:45 p.m. to 5 p.m. (instead of a couple of hours earlier to take full advantage of the hottest time of the day), the oven bag interior still gets to about 225 degrees, which is plenty for slow roasting root veggies and cooking lots of other things. One of our favorite things to solar cook is roasted garlic. Set it out in the early afternoon and it's ready just in time for appetizers.

Oven bag interior nearing 225 degrees

Yesterday I harvested a colander full of heirloom tomatoes in the morning, but didn't want to turn on the stovetop to deal with them. Solution? Solar cooker! Rachel at Dog Island Farms posted a recipe for Oven-Baked Heirloom Tomato Sauce last week that was the inspiration for my solar cooked version. I had slightly different ingredients--white onion from my yard instead of yellow, and leftover red wine instead of white--but no matter. A couple of hours after throwing this on the rack, I had a gorgeous pan of almost-sauce that only needed a quick whirl in the blender.

Ingredients for slow solar-cooked tomato sauce

I foresee lots of solar cooking throughout the rest of summer, especially if these super hot days stick around. I'm probably not going to cook a chicken in this thing, but it works beautifully for lots of other foods. Recently someone suggested I might be able to use it to dehydrate and dry foods, which is an intriguing idea worth pursuing. Actually, I think the possibilities are kind of endless!


  1. So funny that you posted this just as my 85 year old grandmother emailed me the directions for making a solar oven (almost exactly the same as you described)! She puts chicken thighs in a tomato based sauce in a roasting pan and cooks them in her solar oven. It scared me at first (from a food safety standpoint) but after she showed me that the oven reaches 350 degrees in her back yard, my fears were put to rest! It is just like a crock pot slow cooking the chicken but it is powered by the sun. Can't want to try it!

    1. Wow! I haven't gotten mine to reach 350 degrees yet. Maybe I'll have to make some modifications, or start earlier in the day. I was concerned about food safety, too, but it heats up and passes out of the scary temperature zone (40-170 degrees I think) very quickly, so I don't worry.

  2. It's a good idea to get a few, perhaps one square or round one and one rectangular one, so that you have both enough and the right size for the particular baked item.

  3. Love the sunshade oven for tailgating,etc. But, wanted to put folks' mind at rest re solar cooking vs slow cookers. Natl standard for low in a slow cooker is 170F and the high is 190-205F. Solar cookers reach 200F and above in about 20 minutes and will often go much higher (mine averages 275F to 300F, consistently, more like using a moderate oven than a slow cooker). We are now a nation enthralled on slow cookers so, to me, solar cooking is going one better and very like manna from Heaven because it's fun, free, and green!