The Fine Details of Dehydrating Tomatoes

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Dried tomatoes

This time of year you will hear a steady hum at my house, but it’s not the air conditioner. The food dehydrator’s little fan spins hour after hour, generating the sweet aroma of drying tomatoes. While I do can and freeze some tomatoes, every year I dry several batches, too. Compared to other storage methods, dried tomatoes take up much less space than frozen or even canned ones, and preparation goes fast – simply slice clean tomatoes and start dehydrating them.

I dehydrate tomatoes and lots of other food crops in an electric dehydrator, but if you live in an arid climate you can use a solar dehydrator instead. Tomatoes are around 93 percent water, so even in an electric dehydrator they take a long time to dry. Without a constant flow of forced warm air to hasten the drying process, tomato pieces can quickly become buttons of mold.

May we pause for a mini-rant? The ‘net is overflowing with recipes for sun-dried tomatoes that never see the sun, with claims that anyone can make them – in an oven! Sorry, but this is no way to actually dehydrate tomatoes. You can use the oven to slowly bake tomatoes until they collapse, and serve or freeze them as delicious "half-dried" tomatoes, but the oven cannot handle the second half of dehydrating tomatoes, in which they change from soft goo to richly colored leathery pieces. For this, you need a proper electric or solar dehydrator, which bathes tomatoes in a gentle wind of warm, dry air.

Fresh and dried tomatoes

Best Tomatoes for Drying

All types of tomatoes can be dried, and I think drying is the best way to preserve juicy cherry tomatoes and large slicing tomatoes that never found their way to a sandwich. These and other high-moisture tomatoes make a watery sauce that can be bitter if the seeds are not removed with a food mill or sieve, but they dehydrate into flavorful tidbits just right for adding to cooked dishes like pasta salad or chili.

Comparatively dry-fleshed paste tomatoes can be dried, too, and they tend to dry faster than juicier types. I think paste tomatoes are at their best when diced and canned, but one of the great things about dehydrating tomatoes is that you can mix up different types – whatever is ripe that day can go into the dehydrator.

Sliced tomatoes

Preparing Tomatoes for Drying

Tomatoes for drying must be cut by hand, and for this you will need a sharp serrated knife that cuts clean and fast. Cut cherry tomatoes in half, and slice larger salad tomatoes into quarters. Bigger tomatoes are best sliced just under one-half inch (8-9 mm) thick. Thinner slices dry unevenly and are prone to turning dark as they dry. You can cut the slices in half to hasten drying.

You may also elect to first remove the tomatoes’ skins, by dipping them in boiling water for a few seconds, but I think the skins provide beneficial structure during the dehydration process. Besides, when you rehydrate dried tomatoes, or put them in a soup, the skins naturally float free and are easily fished out of the pot should you deem them to be excessive fiber.

Seed removal is optional, too. The gel and seeds contain flavor compounds and nutrients that I like to keep intact when drying tomatoes. Why not have raw, whole food with all its flavor features intact?

Tomatoes drying on dehydrator trays

Dehydrating Tomatoes in Stages

Home food dehydrators circulate warm air continuously, but not uniformly. Some trays dry faster than others, so it is usually necessary to rotate the trays around every few hours to achieve even drying. This is important when dehydrating tomatoes, because you cannot move the pieces until the drying process is almost finished. Tomatoes go through a gooey stage as they dry, which starts 3-4 hours into the drying process and persists until they are almost done. If you try to pick them up during this period, they will tear apart. But if you are patient and wait until the tomatoes flatten into flakes or shrivel into tomato raisins, they are easy to peel from the trays in one piece. In my dehydrator, this takes between 8 and 10 hours.

Like other foods, dehydrated tomatoes benefit from a period of conditioning. I put the newly dried pieces in a big jar, screw on the lid, and keep it at room temperature for a day. Moisture levels equalize between the pieces, after which they almost always feel damp and sticky, which earns them another hour in the dehydrator, arranged in loose piles. Then they are ready to store in airtight containers in a cool, dark place, or in the freezer. They’ll last for six months at room temperature, but in the freezer, dehydrated tomatoes are still perfect after a year.

Dehydrating tomatoes is the best way I know to fit fifteen pounds of tomatoes in a one quart jar, with each piece in recipe-ready condition.

Barbara Pleasant

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Show Comments


"I've read somewhere about drying tomatoes on the back shelf of a car in the sun , I guess you'd need a window open? would this work Barbara"
diverte on Saturday 8 August 2015
"why do my dehydrated tomatoes turn black"
sally on Thursday 8 September 2016
"I have left/ stored dehydrated tomatoes in a paper bag for over a year, with no bugs, no mold or moisture problems. FYI"
Pat Hayburn on Wednesday 14 September 2016
"This will be my first attempt at drying tomatoes. We have plenty in the garden, and I do not like paying the price for "sundried" tomatoes in the grocery store!! Have Romas, a Heirloom canning variety, 3 colors of cherries, and a stupice. Hope the cherries will all dry to a different color.... gold, red and black cherry. Should be fun to try."
Kathy on Sunday 2 October 2016
"This will be my first attempt at drying tomatoes. We have plenty in the garden, and I do not like paying the price for "sundried" tomatoes in the grocery store!! Have Romas, a Heirloom canning variety, 3 colors of cherries, and a stupice. Hope the cherries will all dry to a different color.... gold, red and black cherry. Should be fun to try."
Kathy on Sunday 2 October 2016
"I do have tomatoes in my garden however they are green. I had to plant tomato plants 3 times this spring/summer! One - the Cut Worms had a feast and chopped them. Second - the heat and extreme dry weather for eastern Ontario did its nasty drying work (regardless of the drip hose) so planting tomatoes so late leaves me with a bounty of green. Any thoughts about dehydrated green tomatoes? or what I can use them for? and can they be used in recipes? Merci! Thank you!"
JG on Wednesday 5 October 2016
"You can slice and dredge green tomatoes in cornmeal and fry them. Yummm! You can also make a garden relish with them that is a true feast to the taste buds. "
Carolyn on Friday 14 October 2016
"Barbara, Very good article. I do have to disagree with you comments on "sun drying" in an oven. That's what I've been doing for over 30 years. The trick is to use the oven's lightbulb as your heat source. I use a 100 watt one (though a friend uses a 150 watt)and it takes several days to dry. I dry medium sized tomatoes like Early Girl or Super Fantastic, coring the stem end and slicing from the top so fall in florets. A very light vinegar mist inhibits molds. The slower drying seems to produce more sugars similar to raisins. Putting them in olive oil makes a super yummy oil."
Steve DeVries on Saturday 22 October 2016
"My dehydrator dried tomatoes are 3 years old. Are they eatable?? They kind of smell funny? Not bad smell just...unusual? Donna, Janury 13, 2017"
Donna Chucka on Friday 13 January 2017
"I ended up canning many green tomatoes for a Salsa Verde. The balance i wrapped individually in paper/newspaper and stored them in a box in the garage. Most ripen wonderfully and I lost the balance to mould/ end rot. I do dehydrate in my oven as it has a Dehydration Cycle. It runs for a long time as well. Slow and steady. "
JG on Thursday 26 January 2017
"My first attempt at dehydrating tomatoes. I'd like to flavor them with herbs and such, What herbs are good? finely chopped? how and when do I apply the flavoring?"
Janyce Granetzke on Saturday 2 September 2017
"Love the rant Barbara, it's easy for one to think baking is some how preservation with all the misinformation out there! "
Brock Ingham on Saturday 2 September 2017
"I followed your directions and was so I even stored in jar on counter for one day. When I was ready to do the second dehydrate, they were moldy??? What happened? Not dry enough or should they always be fridged?"
Arlene on Sunday 10 September 2017
"Not sure at what temperature to I should set my dehydrator. Was thinking 135. Does that sound ok?"
Jay on Tuesday 31 July 2018
"Due to an oversight on my part, I never saw these excellent comments. Dried tomatoes that turn black were cut too thinly or dried at too high a temperature. It happens with some varieties more than others. In my climate dried tomatoes pick up humidity and cannot be kept in a bag at room temperature. Dried tomatoes still hold a lot of sugar, and with enough moisture present in the air they can mold. I store mine in vacuum sealed bags or in the freezer."
Barbara Pleasant on Wednesday 29 July 2020
"Barbara, I made four small jars of dehydrated tomatoes and put some garlic in the jars with Italian seasonings and fill with EVOO. I heard somewhere that the seasonings can go bad on occasion so I added a teaspoon of Red Wine Vinegar to each jar and I keep the jars in my wine cooler at about 50 degrees. Can I keep these for many weeks? Some people say they last a long time and others say use within a week. Thanks for your reply. "
John Quinn on Monday 31 August 2020
"Thanks so much fo rthis helpful site. I would like to see answers to many of the questions above. "
Margaret Campbell on Monday 7 September 2020
"I accidentally had my dehydrator set at 95 instead of 135 overnight with tomatoes in it. They are still very watery. Do you think they will mold? The dehydrator was constantly blowing air, just at a lower temperature. I have it on the correct setting now but not sure if I should throw out this batch? "
Amalia on Monday 29 August 2022
"Take any tomato skins you have (from canning, etc) and dehydrate them. Once dried, use a coffee grinder or other method to turn them into tomato powder. A way to season soups and such and the skins contain a lot of nutrients."
Leslie on Thursday 3 August 2023
"Should you put parchment paper on your rack when drying tomatoes "
Linda on Monday 25 September 2023

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