When it comes to preserving food, dehydrating is the least-glamorous option, exiled from most cookbooks and conversations while canning and freezing get all the attention.
Culturally speaking, that’s in line with our gravitation to beauty and youth: Canning and freezing technologies have been around only for a couple centuries; dehydrating began as early as 12,000 B.C., according to the National Center for Home Food Processing and Preservation. But it’s not just the caveman dieters among us who appreciate this simple technique. Dried foods aren’t always the prettiest (dehydrating darkens and wrinkles them), but they’re the lightest-weight and arguably have the purest flavor of anything preserved.
“A dried peach tastes peachier than a fresh peach,” writes Deanna DeLong in her comprehensive guide “How to Dry Foods” (HP Trade, 2006), which was first published in 1979. That’s because dehydration removes water, leaving behind the essence.
In a professional kitchen, any chef will tell you, dehydrating is all about flavor concentration.
“Food preservation techniques like dehydration allow me to buy fruits and vegetables at the peak of the season and preserve them through the winter months to add pop to winter dishes,” says Michael Bonk, executive chef of the Pig in Washington, D.C.
Bonk considers dehydration a versatile, fundamental skill, not to be dismissed in this time of fascination with ultra-modern practices. In fact, the most challenging requirement is patience: Most everything needs a minimum four hours.
“The key is to forget about it,” says Michael Friedman, executive chef and co-owner of D.C.’s Red Hen.
Among other things, Friedman dries cherry tomatoes (packing them in olive oil) and has been substituting dehydrated blackberries for raisins in ice cream and other desserts.
When blackberries are peaking, that makes them perfect for dehydrating — the first rule of which is to use fruit and vegetables at their peak maturity when flavor and nutritional value are greatest. “If it’s prime for eating, it will be prime for drying,” says DeLong.
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.
There’s another natural method you’ve likely seen but maybe didn’t connect with dehydrating. Traditional New Mexican ristras are strings of chilis that can hang in the sun, under cover, or indoors, until dried. “When you hang them, you just hang them,” says Jinich. Use strong thread or fishing line to string the chilies, directly under the stem. Make a knot to leave space between each one. Hang, and don’t expect them to be ready for at least three weeks. Jinich uses dried chilis throughout her cooking, including blending anchos (dried poblanos) into ground beef to make a Mexican twist on hamburgers.
Advantages to using the sun: the bright resulting colors and possibilities of batches bigger than can be done in ovens and dehydrators. But DeLong points out disadvantages, too: Nutrients are lost from the lengthy exposure to sun and air, and foods are less sanitary than those dried in the oven or a dehydrator.
DeLong, a home economics teacher before she turned her attention to dehydrating, has traveled the world teaching best practices to countless people in varying cultures. While Friedman says a home oven is a fine option (“You just need a little more time”), DeLong prefers a dedicated machine. Though fine for someone experimenting, “An oven should be a last resort unless you have a convection with a very low temperature.”
Convection ovens have a fan to move air, and an outlet to remove moisture. Exhaust systems are helpful too, so you don’t have to leave the door open. But the difficulty of controlling temperature and air circulation can produce darker, less flavorful results.
While produce is easy and relatively safe to dry, the technique needn’t be limited to fruits and vegetables. At the Red Hen, Friedman dehydrates ricotta salata (a semi-firm sheep’s milk cheese whose curds and whey are pressed and dried before aging) so he can grate it. At the Pig — where they buy whole animals and try to avoid waste — Bonk dehydrates skin to make cracklings. “The process is pretty straightforward,” he says, “but it took me several attempts to understand the nuances of pork rinds to get consistent results.” Unlike produce, meats need to be first cooked to a temperature that kills bacteria and then kept at a certain temperature for drying safely.
Besides the Paleolithic-inclined and backpackers, raw-food devotees have long used dehydrating in their eating. “Dehydrating allows you to keep enzymes intact,” says Jonathan Seningen, executive chef at Elizabeth’s Gone Raw in Washington, who makes “pasta” from zucchini slices. “All the nutrients are available for your body to digest and take advantage of.”
DeLong sees many reasons — health, budgetary, environmental — for dehydrating. But one simple reason may trump them all, she says: “It makes great food.”
