For larger slicing tomatoes, cut into slices about 3/4 inch thick. Do your best to make the slices consistent in size.
Dehydrating
Lay your tomatoes on the dehydrator trays. Don't let them touch and try not to overcrowd.
Set the dehydrator to 135 degrees F.
Allow them to dehydrated for 4 hours and then check on progress. If your trays are moveable, rotate them so that the trays on the bottom are now on top.
Dry another 4-6 hours, or until the tomatoes are dry and chewy without any moisture when you touch them.
Store in a jar or zipper bag at room temperature for 3-4 months (dry climates) or in the fridge/freezer for up to 6 months (humid climates).
Notes
Serrated/bread knives, as well as cheese knives, work best for cutting through the soft skin of tomatoes without crushing them.
It’s optional to remove the skins, but it’s very easy if you choose to do so. Simply place tomatoes in boiling water for 30-60 seconds, and then scoop them out with a slotted spoon and blanch in ice water. The skins will slip right off! Dry the skins alongside the tomatoes for making tomato powder.
Oven-Baking: Place tomatoes on baking drying racks set inside baking sheets. Place in the oven at the lowest temperature possible (usually 140-170 degrees F) and prop open the door with the handle of a wooden spoon. This allows condensation to escape instead of just settle back onto the tomatoes. Bake for 5-8 hours.