Slow Roasted, Dehydrated Tomatoes

Slow-roast, dehydrate, and freeze lackluster autumn tomatoes; turning them into bursting orbs of flavor!

Autumn is here and the garden is ready for a nap. There are still a few tomatoes though. They struggle to turn red, and the shorter days have left them less sweet than their August counterparts, but I cherish each and every one of them. Summer-ripened paste tomatoes are snuggly preserved in Ball jars, and sweet, little cherry tomatoes are dried and waiting to grace wintertime meals. But finicky autumn tomatoes need extra care to turn them into yearlong treat. It’s a little bit of work, but if you, like me, are loath to waste even one promising tomato, the extra work is worth the sweet, piquant, end result.

Salvaging Autumn Tomatoes

If you have an excess of half-ripened slicing tomatoes, you may wonder what to do with them. They seldom ripen on the vine, and even if you bring them in to ripen on the windowsill, they lack sweet summer tomato taste. A few years ago I started salvaging late tomatoes, almost as an afterthought. Now, I start each season planning to preserve at least one batch by slow-roasting, dehydrating, and then freezing late tomatoes. Yes, there are several steps, but the oven does most of the work.

You can follow this basic process with any type of tomato. I use slicing tomatoes here, but paste tomatoes will no doubt work also.

First, bring the tomatoes inside and let them ripen on the windowsill.

Slow-Roasting Tomatoes

This step can either be done overnight, or on a day when you are home.

Cut out any bad spots or scars, and core the tomatoes. Slice each in half crosswise. It doesn’t matter how large the tomato is, slice it in half, not into slices.

Cover a large baking sheet with parchment paper. Lay each tomato half, cut-side up, on the paper. Tomato halves should not be crowded, and should have a little space between them.

Drizzle tomatoes with olive oil. Sprinkle with a little salt and ground basil (optional).

Roast at 200 degrees for 6-8 hours. Smaller tomatoes may start to burn after 5-6 hours (and cherry tomatoes should be checked after 2 hours). Larger tomato can be slightly “smooshed” with a spatula after 3 hours or so. Remove any tomatoes that are starting to scorch. If tomatoes are still fat and bubbly, you can either continue roasting them for another hour or two, or they can be removed from the oven now.

Dehydrating Tomatoes

Transfer the roasted tomato halves to a dehydrator tray (I use the spatula for this step). The tomatoes may be soft but don’t worry. Dehydrate at 135 degrees for another 4-8 hours, watching to make sure that they don’t burn during this time.

Freezing Tomatoes

Once the tomato halves have dehydrated enough to be a bit sturdy, I layer them in freezer containers and pop them in the freezer to use later. It’s ok to place them on top of each other, the oil keeps them a bit separated so they are easy to retrieve.

Using Slow-Roasted, Dehydrated, Frozen Tomatoes

These tomato halves find their way into many dishes. To use, I simply thaw one or two at a time. Then I use kitchen shears to snip them into small pieces that are bursting with rich flavor. They are perfect in any pasta entrée or pasta salad, added to rice or quinoa pilafs, and tucked into omelets or scrambled eggs. Use them in any recipe that calls for sun-dried tomatoes or chopped fresh tomatoes.

Tomato Hints and Tips

As you can tell, this “recipe” is not set in stone. Use as many or few tomatoes as you have available. Drizzle olive oil lightly or with a heavier hand. Add dried basil or oregano or don’t. Roast for 6 hours or 8 hours or more. Dehydrate until you are ready to stop dehydrating. This recipe is all about personal preference.

If you find your tomatoes all frozen together, set the container out on the counter for a few minutes until they loosen. Remove the tomatoes you want to use, and put the rest back in the freezer.

Have too many green garden tomatoes? Turn them into Best Ever Green Enchilada Sauce!

by Renee Pottle

Renee Pottle, a freelance writer and Home Economist, is fanatic about all things food. She blogs about canning and food preservation at Find her professional food writing info at

September 27, 2021

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