By Sara Pepitone
The Washington Post
WASHINGTON, D.C. —
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 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 Red Hen in Washington.
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."
Ancho Chili Burgers With Lime Aioli
8 to 10 servings
The seasoning paste, made with ancho chilies (dried poblanos), is easy to pull together and works wonderfully with the rich mix of ground meat. To dry your own for this recipe, see the NOTE below. The burgers can be cooked in a cast-iron skillet instead of on the grill.
MAKE AHEAD: The hamburger meat can be seasoned, covered and refrigerated for up to 1 day in advance. The aioli can be refrigerated for up to 2 days. Adapted from "Pati's Mexican Table: The Secrets of Real Mexican Home Cooking," by Pati Jinich (Houghton Mifflin Harcourt, 2013).
For the burgers
4 dried ancho chilies (2 ounces total) rinsed, stemmed and seeded (see NOTE)
1 cup coarsely chopped onion
3 cloves garlic
1 1/2 pounds ground beef
1 1/2 pounds ground veal (may substitute ground meat of your choice; try equal amounts of pork, veal and beef)
2 large eggs, lightly beaten
1 1/2 teaspoons kosher or coarse sea salt, or to taste
1/2 teaspoon freshly ground black pepper, or to taste
Mexican Manchego or Monterey Jack cheese slices (optional)
Hamburger buns, for serving
For the aioli
1 cup regular or low-fat mayonnaise
1 teaspoon finely grated zest and 2 tablespoons fresh lime juice
3 cloves garlic, minced or pressed
1 teaspoon kosher or coarse sea salt, or to taste
1/4 teaspoon freshly ground black pepper, or to taste
For the burgers: Prepare the grill for direct heat. If using a gas grill, preheat to medium-high (450 degrees). If using a charcoal grill, light the charcoal; when the coals are ready, distribute them evenly over the cooking area. For a medium-hot fire, you should be able to hold your hand about 6 inches above the coals for 4 or 5 seconds. Use cooking oil spray to grease the grill grate and place on the grill. Have ready a spray water bottle for taming any flames.
Place the dried chilies in a small bowl and cover with boiling water. Soak for 10 to 15 minutes. Use a slotted spoon to transfer them to a blender, then add 2 tablespoons of the soaking liquid (discarding the rest), the onion and garlic. Puree until smooth.
Combine the ground beef and veal in a large mixing bowl. Mix in the chili puree, eggs, salt and pepper. Use your hands to shape the meat into 8 to 10 large patties.
Arrange the patties on the grill; cook uncovered for 5 minutes per side (medium-well).
Meanwhile, make the aioli: Whisk together the mayonnaise, lime zest and juice and garlic in a medium bowl. Season with salt and pepper to taste. The yield is about 1 cup. Cover and refrigerate until ready to serve.
Place a slice of cheese, if using, on each hamburger a few minutes before the second sides are done. Transfer to buns for serving, along with the lime aioli.
NOTE: Anchos are dried poblanos. To dry poblanos (and other peppers), choose peppers at their peak - free of decay, mold and bruises. Rinse and dry.
There are three ways to dry them; after they're dried, pack the ancho chilies in zip-top bags or airtight containers:
1. Lay them in direct sun for 6 to 10 hours on woven mats or another platform that allows air to circulate underneath. Cover when the sun sets. Repeat each day for 3 more days.
2. Thread clean fishing line through the stem of one poblano, leaving at least a knot's worth of space before threading the next one. Hang in a dry room with good air circulation for about 3 weeks, until the peppers are dry yet pliable.
3. Preheat the oven to the lowest temperature. Arrange the poblanos on baking sheets. Dry in the oven for 10 to 12 hours, leaving the oven door slightly ajar, turning the peppers every few hours, until dry yet pliable. Cool completely before storing.
NUTRITION Per serving (based on 10, without the buns, using low-fat mayo and 1 tablespoon aioli per serving): 280 calories, 29 g protein, 7 g carbohydrates, 15 g fat, 5 g saturated fat, 140 mg cholesterol, 650 mg sodium, 2 g dietary fiber, 0 g sugar
Oven-Dried Cherry Tomatoes in Olive Oil
Makes about 2 cups (including oil)
Serve as snacks or appetizers; use in salads, pastas and more - including the oil.
MAKE AHEAD: The tomatoes need to dry in the oven for 2 hours, and they need to marinate in the refrigerator for at least 1 hour and up to 1 month. Adapted from Michael Friedman, executive chef and co-owner of the Red Hen in D.C..
1 pound mixed bite-size tomatoes, such as grape or cherry tomatoes varying in size and color
1 tablespoon kosher salt
2 sprigs fresh thyme
2 sprigs fresh oregano
One 3-inch sprig rosemary
6 basil leaves
1 1/2 cups extra-virgin olive oil
Preheat the oven to 200 degrees. Line a large rimmed baking sheet with parchment paper.
Rinse the tomatoes in cold water then dry them with paper towels. Use a serrated knife to cut each one in half and place in bowl; toss with the salt until evenly coated.
Line a baking sheet with parchment paper; spread the tomatoes on it. Dry for 1 hour in the oven, then rotate the baking sheet from front to back and dry for 1 hour. The tomatoes should look slightly dehydrated but still have a bit of moisture; think tomato raisins. Cool completely.
Transfer the oven-dried tomatoes and the herbs to a sterilized pint jar. Fill with the oil, making sure the tomatoes and herbs are submerged. They will be loosely packed.
Seal and refrigerate for at least 1 hour and up to 1 month.
NUTRITION Ingredients are too varied for a meaningful analysis.
Makes 4 ounces (8 servings)
Puffed and savory, cracklings are good for snacking or garnishing other dishes.
The first step is sourcing the pork skin. You can make pork cracklings out of any portion of the skin, but the belly skin produces the puffiest and best product. Check with your local butcher or local market. If you can't buy just the skin, try to buy a skin-on portion of pork belly. Then you get a double win: delicious pork belly and skin for cracklings.
MAKE AHEAD: The pork belly skins need to be cooked in water for 45 minutes and cooled completely in that liquid. The skins take 12 hours to dry in a minimum-temperature oven. The cracklings are best eaten when fresh; they can be stored in an airtight container or frozen for a few months. Adapted from Michael Bonk, executive chef of the Pig in Washington.
1 pound pork belly skins (see headnote)
Peanut oil, for frying
Kosher or seasoned salt (optional)
Trim as much fat as possible from the skins and discard.
Submerge the skins in a pot of barely bubbling water over medium heat. Cook for 45 minutes, then remove from the heat. Cool in the liquid. Remove the skins and place on a flat surface. Use a spoon to gently scrape off any remaining fat, taking care to not tear the skin. Cut the skin into about fifteen 1-by-3-inch pieces.
Preheat the oven to 200 degrees. Seat an ovenproof rack inside a large rimmed baking sheet.
Place the skin pieces, fat sides down, on the rack. Dry in the oven for 12 hours. The pieces are ready when quite brittle. Gently scrape away any remaining fat.
Line a baking sheet with several layers of paper towels, then place a wire rack over it.
Heat about 3 inches of oil in a large deep pot over medium-high heat, to a temperature of 375 degrees. Deep-fry in batches, about 4-5 at a time. The cracklings will expand to several times their original size and turn golden brown. The oil should bubble furiously around them. Use tongs to transfer to the rack to drain. Immediately season with salt to taste, if desired.
Serve warm, or cool completely before storing.
NUTRITION Ingredients are too varied for a meaningful analysis.
Serves 2 as an entree, 3 to 4 as an appetizer
Chef Jonathan Seningen of Elizabeth's Gone Raw cuts zucchini into thin slices, then puts the slices into a dehydrator for a brief time. The dehydrator is set at 115 degrees, which is a generally accepted threshold for food to be still considered "raw," and the process softens the texture of the vegetable so that it resembles pasta. Serve with pesto, tomatoes and olive oil, or another raw pasta topping.
This technique also works with peeled butternut squash.
You'll need a dehydrator with specific temperature settings for this recipe. From Jonathan Seningen, executive chef at Elizabeth's Gone Raw in Washington.
1 medium (about 10 ounces) zucchini, cut crosswise into 1/8-inch rounds
About 2 tablespoons olive oil
Freshly ground black or white pepper
Toss the zucchini and oil in a mixing bowl to coat evenly. Season with salt and pepper to taste. Arrange the rounds on racks in the dehydrator; set the temperature to 115 degrees. Dry for 25 to 45 minutes, or until light-colored patches of moisture disappear and they have achieved the consistency of al dente cooked pasta.
VARIATION: To make zucchini "ravioli," start with an even number of the dehydrated rounds. Arrange half of them on a platter. Pipe a dollop of cashew or other nut cheese (see NOTE) or other savory filling at the center of each one. Top with the remaining rounds, pressing gently around the edges to form ravioli. Serve as hors d'oeuvres or with pesto or fresh tomato sauce.
NOTE: To make 1 cup of cashew cheese, soak 1 cup of cashew pieces in water for 4 hours. Drain and rinse them, then put in a blender or food processor with 1 tablespoon miso (chickpea or white), 2 teaspoons chopped shallot, 2 teaspoons fresh oregano leaves, 1/4 cup chopped celery and 1 teaspoon fresh lemon juice. Blend until smooth. Covered, the mixture will keep in the refrigerator for 4-6 days.
NUTRITION Per serving (based on 4): 70 calories, 0 g protein, 2 g carbohydrates, 7 g fat, 1 g saturated fat, 0 mg cholesterol, 65 mg sodium, 0 g dietary fiber, 1 g sugar