Because dried citrus keeps its color, flavor and scent, it is often included in potpourri mixes. The fruits from citrus trees (Citrus spp., U.S. Department of Agriculture plant hardiness zones 9 though 11) are easy to dry in a kitchen oven, so you don't even need a dehydrator. Lemons and oranges add their aroma to many potpourri recipes, but you can also use other citrus fruits such as limes.
To help preserve the color of citrus fruits and kill any bacteria, soak the peels and slices in ascorbic acid before drying. Mix 3 3/4 teaspoons of pure ascorbic acid crystals with 2 cups of cold water in a bowl, then soak the fruit slices or peels in this mixture for 10 minutes. Remove from the solution and drain well before baking. Ascorbic acid is available in supermarkets and drugstores.
Preheat the oven to 150 degrees Fahrenheit.
Cut citrus fruits into slices 1/4 inch thick. Discard end pieces, and soak the slices in ascorbic acid.
Place wire racks on baking sheets, and put the sliced fruit out on the racks. Make sure the slices don't touch.
Bake slices in the preheated oven for four to six hours. When they are done drying, the slices will start to curl at the edges and will feel dry but pliable.
Preheat oven to 140 degrees Fahrenheit.
Use a knife to thinly peel the outer skin of the citrus fruit. Cut the peels 1/16 to 1/8 inch thick, then soak them in ascorbic acid
Lay out the peels on a baking sheet, without a wire rack. Make sure the peels are in a single layer and do not overlap.
Bake peels in the preheated oven for about eight to 12 hours. Stir the peels every three to four hours to prevent scorching, and remove them once they are crispy-dry.
Let dried slices or peels cool completely after baking. If you're not using them immediately, store dried citrus fruit in sealed containers in a location that is cool, dark and dry.