Expanding Dehydrating Capacity With What I Have and How This Could Apply to You

My suggestions below are only for dehydrating plant foods and not meats.

My 1995 dehydrator originally came with 4 racks. A few years ago I bought 2 additional racks on ebay to expand capacity. Six racks do the job for me when I'm doing herbs or smaller amounts of fruits or vegetables. However, when I'm dehydrating fruit in late summer, I really need more capacity. I achieve this by using one of my ovens in addition to the dehydrator. 

Dehydrating foods require different temps depending on what they are. Recommended temperatures:

• herbs -- 95 degrees F
• mushrooms -- 100 degrees F
• vegetables -- 115 to 130 degrees F
• fruits/fruit leather -- 125 to 135 degrees F

Two options with using your oven to dehydrate herbs and foods 

1) What's the lowest setting that your oven uses with its element? I have two large ovens, one as part of the range/stove and the other, a wall oven. My wall oven can only go as low as 170 degrees F. But my oven as part of my range can go as low as 100 degrees F. I also have a small countertop oven (a toaster oven) that can heat as low as 90 degrees F. It's much smaller, so would have less capacity, but it could be used in a pinch. Just saying, in case the only oven you have that heats low enough is a countertop oven. You could do small amounts of fruits, fruit leather, vegetables, herbs, mushrooms, etc.

2) The second option works best with herbs or mushrooms, but you can test to see if the light provides enough heat for vegetables or fruit. Some oven lights do warm the oven to higher temps than others. You will need to check the temperature of your oven, using a non-instant read meat thermometer (old-style, mercury in the tube), a non-instant candy thermometer, or an oven thermometer. Turn the light on for your oven, place the thermometer in the middle of the center rack inside the oven, close the door, and wait 30 minutes. 

If your oven warms to a high enough temp with just the light, dehydrate herbs/foods by leaving in the oven (on metal cooling racks, like cookie racks, set on top of a sheet pan) with the light on and the door closed. If the temp is slightly too high, you can leave the light on with items inside and something to keep the door from closing completely, like a wooden spoon or silicone oven mitt or potholder stuck into the opening of the door, allowing a small crack in the opening, enough to vent and allow some warmth to escape.

Tips for using your oven

It's important to place your fruits/veggies on racks on top of a metal tray to create some air circulation around the foods. If your oven also has the convection option, use it. If your racks have slots that are too far apart (food will fall between as it dries), line the rack with parchment paper. The foods will still benefit from air circulation on the parchment. Check foods and turn over once an hour until done. Don't crowd racks used in the oven. If you can, crack the oven door to allow greater air circulation.

You can fudge on the temperatures by about 10 degrees higher than stated ideal. However, anything warmer than 140 degrees F will basically cook the foods and not dehydrate them.

This is how I've been dehydrating plums and apples this month, using my oven in addition to the dehydrator. I've expanded my capacity by about 3 to 4 dehydrator-size trays, without purchasing additional trays. As I said above, it's only a few weeks out of the year that I need extra dehydrating capacity, so it makes sense to find other ways to do this using what I have. 

One p.s., if you want to try dehydrating herbs, fruits, veggies in your car parked in the sun on a sunny day, check the temperature of your car's interior as discussed above for checking your oven temp with the light. Crack windows to both allow air circulation as well as adjust interior temp.