Wellness gurus swear by the magic of heat—sweat it out in a sauna, stretch it out in hot yoga, burrow under a heated blanket and pretend the world doesn’t exist. Enclosed warmth, they say, is restorative.
Unless you’re a sour grape. Then it’s a reckoning.
My grapes learned this the hard way when I brought home a $12 bag of inedible grapes. They tasted amazing in the store - probably because I had just tried another grape that was so sour it made my mouth pucker into a the shape of a hole meant for exits, not entrances.
Who hasn't experienced the disappointment of a pucker inducing grape. But you can't throw them all out because you just bought them.
You could leave them in the fridge until they look as inedible as they taste or you can do with I did.
I did what any logical person would do: I sent the grapes to a wellness retreat so they could become their best selves.
How to Make Raisins from Grapes in a Dehydrator
What You’ll Need
- A dehydrator
- Grapes (the sad, sour kind work great)
- A pot of boiling water (optional)
- A bowl of ice water (optional)
- A colander
- A clean kitchen towel
- A glass jar with a lid (for conditioning)
Step 1: Wash & Prep the Grapes
First, wash the grapes because who knows where they’ve been. Wash them BEFORE you pull them off the stems.
WHY?
Keeping the grapes on the stem while washing helps prevent pesticides, dirt, and bacteria from being rinsed directly into the open spot where the grape was attached.
Toss any weird-looking ones. If they’re huge, you can cut them in half. I didn't. I probably should have. Had I only known the secret trick. (more to follow)
Step 2: Dehydrate
Set the dehydrator to 135°F (57°C) and let them go for 24-72 hours. Yes, it’s a long time.
Check them occasionally, and if you see some drying faster than others, swap the trays around or pull the dried ones out. They’re done when they’re wrinkled, chewy, and feel leathery on the outside - not sticky.
When raisins are dried perfectly, they make a distinctive "clicking" sound when you drop them on a counter!
I didn't want to cut my grapes in half because - dammit - I wanted proper raisins.
That choice meant by day 2 of constant drying they only looked like this. Cutting them in half would have cut the drying time by at least half. They needed another 24 hours to fully raisinify.
Step 5: Condition for Perfect Storage
This is the part most people skip, but don’t—unless you like moldy raisins.
Would you like to save this stuff?
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- Once they’re dried, toss them in a glass jar with a lid.
- Shake the jar once a day for a week.
- If you see any condensation form inside the jar, pop them back in the dehydrator for a few more hours.
After a week, if they feel consistently dry, and there are no water droplets inside the jar - you can store them for months.
The raisins were immediately deployed into butter tarts and I was momentary scared they'd just bloat back into grapes. They did not.
I planned to make butter tarts with pecans on the weekend then suddenly remembered I could also put homemade raisins in some and I got a little teary eyed. Food nerd. 🤓
Butter tart recipe from The Cake & Loaf cookbook.
Step 6: Store & Enjoy
Once they’re conditioned, put them in an airtight container and store them in a cool, dry place. They’ll last six months or more, but let’s be honest—they won’t last that long.
Optional Step: Blanch for Faster Drying
Here’s a trick: apparently a quick dip in boiling water helps the grapes dehydrate way more evenly.*
- Drop the grapes into boiling water for 30 seconds—just enough to loosen the skins.
- Immediately transfer them to an ice bath so they don’t keep cooking. At this point the skins will split.
- Dry them and then proceed with dehydrating steps.
This step is optional, but it speeds things up and prevents weird, half-dried, tough-skinned raisins. Instead of boiling the grapes, you could also pierce each grape with a paring knife.
*I didn't discover this tip until I had already made my raisins so I can't say if it works or not but I'll test it.
How to Eat Your Homemade Raisins
- Throw them in oatmeal or yogurt.
- Bake them into cookies or cinnamon rolls.
- Add them to a salad (trust me).
- Eat them straight out of the jar like candy.
- BUTTER TARTS
How to Make Raisins From Sour Grapes
How to make raisins when you bring home sour grapes.
Ingredients
- Grapes
- Dehydrator
Instructions
1. Selecting and Preparing Grapes:
- They can be sour, but they still have to be good quality. Red or green works.
- Wash the grapes under cool water.
- Remove the grapes from their stems. *
2. Preparing Grapes for Dehydration: (this step is optional but will speed things up)
Crack the Skins: Grapes trap moisture inside, slowing dehydration.
- Crack the skins by blanching the grapes in boiling water for 30 seconds then plunging them in ice water. Their skins should beak instantly.
- You can also crack the skins by piercing each grape with a knife to create a place for moisture to escape.
- Pat dry before dehydrating.
3. Arranging Grapes on Dehydrator Trays:
- Put your grapes on the dehydrator trays keeping everything in a single layer
4. Dehydration Process:
- Preheat the dehydrator to 135°F (57°C).
- Depending on grape size, moisture content, and dehydrator efficiency, drying can take anywhere from 18 to 72 hours.
5. Testing for Doneness:
- Properly dried raisins should be soft, pliable, and not sticky.
- They should not have any visible moisture when cut open.
6. Conditioning the Raisins:
- Plop the cooled raisins into an airtight container, filling it about two-thirds full. Seal the container and let it stand for 7 to 10 days, shaking it daily to separate the pieces and check for moisture condensation. If condensation develops, return the raisins to the dehydrator to keep drying.
7. Storing the Raisins:
- Proper Storage: After conditioning, store the raisins in airtight containers in a cool, dark place. If they're properly dried they can be stored for months and months.
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In the end, the sour grapes got transformed, the butter tarts got their raisins, and I got to pretend this was my plan all along.
Hettie
Super idea! I recently purchased a Ninja Foodi Smart which includes a dehydrate function. This will be my first dehydrating experiment. I'll let you know how it goes. Thanks, Karen!
Carolyn
Great idea.
When I get grapes that disappoint me, I clean and pluck them from the stems and add them to the bag in my freezer. When I get a few bags I make grape jelly!
Randy P
I read the title of this post, and immediately thought you were going to quip, "Cheer them up of course". But I was again wrong, fool that I am. Instead, I have now learned how to beat SunMaid at their own game should I ever so choose. Cool beanz.
Teresa Chandler
Aren’t they now just sour raisins?
Inquiring minds want to know.
Karen
LOL, no. They're regular raisins. They're good! ~ karen