How to Dehydrate Strawberries in an Oven

Every year, my mom, my sister, my niece, and I all go strawberry picking together.  And every year my mom and sister enthusiastically head make a mad dash for opposite ends of the berry field, leaving me to fend for my niece.  Did I mention my niece is 5 years old, eats three times as many berries as she picks, and has to “go potty” every 15 minutes?  I didn’t have to worry about that though, because unfortunately this year most of the strawberry crops in my area did not do well.  The crop failed entirely at the farm where we usually pick…they told us they might have something later this summer, but as of yet, nada.  

I decided to buy some local berries instead.  At our local produce outlet, they only had two quarts left on the day we went!  Talk about slim pickings.  (I’ll definitely be back there though.)  Anyway, I snatched them up and since then have been deliberating on how to use my precious loot.  I decided to dehydrate the berries to make my favorite granola. 

I don’t have a food dehydrator, so I used my oven to dehydrate the strawberries.  Here’s how to do it:

You Will Need:

Strawberries (however many you want to dehydrate; remember they shrink down a lot)

A little canola oil

Baking sheet(s)

Thermometer able to register 140F

An oven

A small fan

Step 1:  Wash the berries and pat them dry.  I find the best way to wash the berries is to fill a clean sink with cold water, add the berries, and gently agitate them around; change the water as many times as it takes for the berries and water to be dirt-free.

Step 2:  Once the berries are dry, hull and slice them.  To hull the berries, insert a paring knife at an angle into the berry near the green leafy top area (called the hull, this is the place where the berry connects to the leafy stem); use a circular motion to cut out the hull, then discard it.  Once hulled, cut the berries into slices ~.25 inches (or 5-8 mm) thick; try to cut the berries uniformly thick so that they dehydrate evenly.  Once they’re sliced the berries are ready for dehydration; some fruits need to be pretreated to prevent them from darkening (like apples), but strawberries are ready to go.

Step 3:  Very lightly grease a baking sheet evenly with canola oil.

Step 4:  Arrange the sliced berries in a single layer so that they don’t touch.

Step 5:  Place the berries in a 140F oven and dehydrate.  Most ovens don’t go as low as 140F, so you should set the oven to the “warm” setting (or as low as it will go) and prop the door of the oven open ~6 inches.  Check the temperature with a thermometer to make sure it stays around 140F; adjust the oven setting as needed (the temperature will fluctuate slightly because of the oven door being open).  The air around the fruit needs circulation, so you can position a small fan near the open oven door (but don’t point the fan directly into the oven). 

Step 6:  Check the berries every 2 hours, and flip them with a thin spatula as needed (I usually flip when they start looking shriveled on one side).

Step 7:  The berries are done dehydrating when you can’t see any moisture left, and they’re not sticky or tacky to the touch, but they’re still somewhat pliable (try not to let them get to the point of being brittle).  If you put the berries in a jar, they should rattle when shaken.  This should take anywhere between 8-20 hours, depending on the heat, humidity, ripeness of the berries, and how thick you cut the berries; for me it took ~10 hours. 

Step 8:  Let the dehydrated berries cool at room temperature for 30-60 minutes.

Step 9:  You should pasteurize the berries to kill any insects and their eggs.  To do this place the berries in a freezer-safe zip-top bag and leave them in the freezer (0F or below) for 2 days.

Step 10:  The last step is conditioning the berries, which is necessary to equally distribute any remaining moisture in the berries, which in turn reduces the risk of mold.  This can be done by placing the berries in a closed jar and leaving it on the countertop for 7-10 days; shake the jar once a day but do not open the jar until conditioning is done.

Step 11:  Enjoy!

You can read more about dehydrating strawberries (and other fruits and veggies) here.