Solar Dehydrated Fruit Without a Solar Dehydrator

A solar dehydrator extends the shelf-life of summer fruit

When I lived at my intentional community, I dehydrated fruit and vegetables in a solar food dehydrator on hot, sunny days. It worked fabulously to dehydrate apple slices and tomato slices and the sun seemed to impart extra flavor in the kale chips I made in it. Covid displaced me and I no longer live at the community unfortunately. I’ve thought about building a solar food dehydrator but perhaps I don’t need one. The other strategies I’ve used to dehydrate food have worked well. (Read more about solar cooking here.)

Car as solar dehydrator

Last October, during California’s devastating climate fires and a heat wave, I dehydrated tomato slices inside a car. I set a cooling rack in a cookie sheet, arranged 1/4-inch-thick slices on it and left the tomatoes in the car for a couple of days. The summer sun will dehydrate them in a day, but I dehydrated these in mid-October, with less sunlight and a bit of morning shade in the driveway. By day two, they had shriveled up to a fraction of their size, after which I stored them in a small, eight-ounce mason jar.

Now, is a hot car the best environment for dehydrating food? This nine-year-old car has off gassed many of its VOCs (volatile organic compounds). But I wouldn’t try this in a newer car. Not only do cars run on fossil fuel, a ton of fossil fuel in the form of plastic goes into manufacturing them (e.g., the plastic console and synthetic carpet, upholstery, seatbelts and so on). Plastic, heat and food don’t mix well. So, I’m not sure if I will do this again. I would love to hear people’s thoughts on this.

Had I an old car windshield, I would spread my food out on trays placed outside and cover them with my windshield. I might look for a windshield on Craigslist, Nextdoor or a junkyard…

using the car as a solar dehydrator to dehydrate tomato slices
Tomato slices dehydrating in a car’s rear windshield on a hot day during last year’s climate fires
using the car on a hot day as a solar dehydrator
Ash from the fires covering the back windshield
tomato slices dehydrated in a car
Finished dehydrated tomatoes

Makeshift solar dehydrator

Last week, we had the first extreme heat wave of the year. On Thursday, the temperature hit 99°F where I live in the San Francisco Bay Area. In the Sacramento Valley, where my daughter MK lives, the thermometer hit 109°F. Since I literally could have fried an egg on the pavement, I decided I would dehydrate blueberries on the concrete.

I placed a handful of blueberries in a glass dish, placed that on a cookie sheet and covered the smaller dish with an overturned glass baking dish. The air vents in the solar dehydrator I had used at the community prevented the solar dehydrator from becoming a solar oven so I wanted at least a bit of air circulating under the glass. The baking dish wasn’t quite flush with the cookie sheet, which let in some air. I carried everything outside and placed it on the concrete patio.

The berries would have fallen through the gaps of the wire cooling rack I used for the tomato slices. I could likely have simply put the blueberries directly on the cookie sheet. A screen would have been nice. (As I write this, I now recall seeing an old dusty screen in the garage a while ago. Next time!).

makeshift solar dehydrator using glass dishes and a baking sheet placed on concrete in full sun
The setup

Blueberries drying in the sun

These dehydrated in a day. Had I let them dry out any longer, they would have dried out more than I like. When I bake with overly dry dehydrated fruit, I’ll reconstitute the fruit with hot water first. But in trail mix or granola, for example, I want dehydrated fruit to contain enough moisture to render it chewy—not crunchy.

Strategies in sustainable living: Make do and try stuff

Making do with what I have forces me to experiment—I try all kinds of things. Most work. Some don’t. When I fail, at least I learn. These berries dehydrated well and now I wish I had more to put outside. I’ll stock up next week at the farmers’ market. I have more pyrex dishes, more cookie sheets and more hot days ahead.

3 Replies to “Solar Dehydrated Fruit Without a Solar Dehydrator”

  1. How to discourage the many squirrels from jumping onto my balcony to enjoy the fresh fruit?

  2. Now, that’s unique to use the car as a dehydrator! My mom used two fine screens to dry lots of fruits, veggies, and herbs. Worked like a charm and kept the bugs out too!

  3. I love the car idea, and your other suggestions. I’ve tried to figure out a diy solar tomato dehydrator for summer, but the flies have won every time. I’ll keep trying.

Leave a Reply