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 only been around a couple of 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. 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,” said Michael Bonk, executive chef of Pig in 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,” said Michael Friedman, executive chef and co-owner of Red Hen in Washington.
Among other things, Friedman dries cherry tomatoes and has substituted 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 you do not have a garden, farmers markets are the best source.
After selecting the “ripest and tastiest” produce, rinse and dry, inspecting for mold or bruises, said TV host and cookbook author Pati Jinich. Don’t dehydrate anything with signs of decay.
When dehydrating produce, you can practice and practice without too much worry about food safety if you start with unbruised fruit.
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 method in some areas, but if you give it a go, use produce with high sugar and acid content for best results. 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 chilies that can hang in the sun, under cover, or indoors, until dried.
“When you hang them, you just hang them,” said 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 chilies throughout her cooking, including blending anchos (dried poblanos) into ground beef to give burgers a Mexican twist.
Advantages to using the sun: the bright resulting colors and possibilities of batches bigger than can be done in ovens and dehydrators. But, 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.
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.