If you do not have a garden, farmers markets and stands are the best source, and some farmers, like Emily Zaas of Maryland's Black Rock Orchards, offer dehydrating advice. Zaas makes and sells dehydrated apples and roll-ups (essentially applesauce dried flat at 125 degrees for eight hours) in the fall and winter. She says Granny Smiths and anything crossed with Golden Delicious (Jonagold, ginger-gold, gold rush) work best.
After choosing the "ripest and tastiest" produce, says TV host and cookbook author Pati Jinich, rinse and dry, inspecting for mold or bruises. Don't dehydrate anything with signs of decay. Unlike with sauces and the like, skip the bruised seconds.
When dehydrating produce, you can practice and practice without too much worry about food safety if you start with unbruised fruit. "You can make mistakes and nearly everything you do is still going to be good," says DeLong.
That's because the absence of water inhibits the growth of microorganisms (bacteria, mold, yeast). These food spoilers are not gone, but they won't multiply until water is re-introduced, returning the food to its perishable state. Worst-case scenario with fruits and vegetables? You see mold, or smell fermentation, and throw out the produce.
Jinich doesn't dry food at her Bethesda, Md., home these days, but she grew up in Mexico around sun-dehydrating, which requires consecutive sunny, dry, breezy days over 85 degrees. Traditionally, food sits on woven mats, whose unevenness allows air to pass through, an integral part of efficient dehydrating, although drying trays and screens also work. The food is covered at night. Because of humidity, this is not the ideal D.C.-area method, but if you give it a go, use produce with high sugar and acid content for best results (grapes, figs, shell beans). Don't try it with meats. Beware of rain.