Late last year at Portland, Ore.’s Castagna, a forward thinking restaurant that places a high value on thought-provoking textures—fluffy piles of flavored ice, silken bits of meat—I hit upon a sweet, chewy nubbin in a wintry elk dish that I couldn’t quite identify. Our waiter said it was a carrot that had been through a dehydrator, one of a few “root raisins” in the dish. Dehydration, he explained, concentrates sweetness, and also produces tender-chewiness almost as substantial as that of tender elk flesh.
It made me laugh to think that a high-end chef like Castagna’s Matt Lightner (who’s recently left for a project in New York City), is using the same tool as survival-minded food storage enthusiasts and adherents of the raw food movement. Of course, he’s not alone: Rene Redzepi at NOMA dries his signature savory meringues in a dehydrator, while Grant Achatz of Alinea concentrates the sweetness of grapefruit by drying it for a couple hours. For these chefs, no doubt, dehydrators are just one tool in a fully stocked kitchen, used to pursue the uncanny textures that are the hallmark of contemporary haute cuisine.
Does a dehydrating gadget also have value in a dabbler’s kitchen—like mine? Slate managed to get me a loaner dehydrator, and I played around with it to find out.
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Dehydration is a truly ancient technique. Before refrigeration, a fresh-killed woolly mammoth was a windfall and a bit of a liability—you couldn’t eat it all before it went bad. If, however, you dried out the meat, you’d have lightweight, protein-rich bits of food to nibble on for months and months to come. The lightness and shelf-stability (or in the case of our earlier hominid relatives, cave-ledge stability) of dried food continues to have its appeal: in the broad swaths of the world where electrical refrigerators aren’t a household given, for backpackers seeking minimal weight in their rucksacks, or for apocalyptically minded survivalists who buy emergency food by the yearful.
In the olden days, people dried food with moderate heat (from the sun) and air circulation (from hanging food or placing it on racks). Today there are a few higher tech options, including freeze-drying, which dries food very thoroughly, with an eerie faithfulness of color and aroma, but is prohibitively expensive. The most basic and accessible contraptions, however, still use moderate heat (from a heating coil) and air circulation (from a fan)—like the test dehydrator that Slate obtained for me from TSM. It’s a bit like a CPU tower without the circuitry—just a big (roughly 1 ½ feet cubed) stainless steel box with lots of ventilation, a fan at the back, and a heater that can warm the air up to approximately 155 degrees. There are 10 removable metal grid trays—allowing plenty of space for experimentation. The model costs about $450 retail, more than twice the price of the most basic entry-level versions with plastic trays and smaller capacities.
When life, or a publication, gives you a dehydrator, it’s natural to make beef jerky. I’ve already written about my fondness for jerky in Slate, but I’d only made the stuff in my oven before, which doesn’t go down to such a low temperature or possess the same airflow as a dehydrator, and my results were more brittle and tough than I would have liked. My recent attempt at beef-drying was not a finesse operation by any means. It took me a while to figure out, with the inexactly calibrated temperature dial, how to hold the dryer at around 150 degrees Fahrenheit, a good meat-drying temperature. And even then I had to hang around to check the meat with some frequency to avoid over-desiccation. My efforts paid off, however: I hit just the right balance between rawhide toughness and too-moist mealiness. I passed my homemade jerky (goosed with a bit of chipotle) around at a cocktail party, and though it wasn’t a typical hostess gift, it went over well with the crowd.
I made another dehydrated favorite, fruit leather, by pureeing some strawberries with a bit of honey and a squeeze of lemon, then spreading the mixture on a film of nonstick acetate. The resulting leather was significantly thinner and more vibrantly flavored than the gummy stuff we usually get at the grocery.
For such traditional applications, it became clear to me that one advantage of having your own dehydrator is being able to control “doneness.” If you’re not worried about packaging your food for really long periods of time, you can go for a slightly moister finishing point—something that retains more fresh-fruit flavor than the standard grocery store dried fruit. (Working with just-in-season fruit helps the flavor, too.) You can dehydrate without common additives, like sulfites, or plumpers like coconut oil or apple juice. Or you can purposely add your own outré additives. I made a batch of dried cherries with fruit marinated in sweet vermouth—a ready-to-go Manhattan garnish.
Not everything turned out perfectly: I bungled a few things in the machine. Raw-food devotees like to make flaxseed crackers from a mucilaginous slurry of seeds soaked in water. I’ve had them before and liked them for their unrelenting homespun crispiness—more granola than granola itself—but my own batch turned out wildly oversalty. (Note to self: Dehydration concentrates the effect of salt.) I also tried to make “onion glass”—a sort of ethereal onion wafer—from Aki Kamozawa and H. Alexander Talbot’s Ideas in Food. I didn’t have any glucose syrup in the house and substituted corn syrup, which might explain why my finished product was less like onion glass than leather—which my friends and family agreed, after tasting, is not something the world needs. And I don’t even want to say how badly my own recipeless attempt at carrot “raisins” turned out.
On the lookout for other, possibly more manageable, modern takes on dehydrated food, I called Chris Young, the co-author, with Nathan Myrhvold and Maxime Billet, of Modernist Cuisine, the six-volume epic devoted to contemporary avant-garde cooking. Young told me that almost, but not totally, dried food—say a piece of mostly dehydrated duck skin (or even more unexpectedly, watermelon)—can puff up exuberantly in the deep fryer. He mentioned the carrot tuiles he’d made when he directed the research kitchen at Fat Duck—you just whiz together juiced carrots and a stabilizer like gellan gum, and dry out the mixture until you get translucent wafers, which are pliable when warm but crisp when cooled off. But for a really simple recipe, at least by Modernist Cuisine standards, he sent along a technique for Watermelon Bulgogi: A vegan sweet-soy Korean “beef.” (Watermelon-as-meat is all over the food press these days; see Mark Bittman’s somewhat recent watermelon burgers in the New York Times Magazine).
I did not complete the full watermelon recipe, which calls for a kimchi of watermelon rind and some homemade Korean chili paste, but I did make the centerpiece. I brined watermelon in a vacuum bag, then dried it for several hours, then seared it in a pan and brushed it with a sweet ginger-soy glaze. After all the pressing and drying, the watermelon draped like a piece of raw meat, and the veining in the fruit actually mimicked a well marbled piece of flesh. (The recipe recommends leaving a thin sliver of the white rind to simulate a beefy fat cap.) Even more weirdly, the texture was juicy-slithery and chewy in a way that closely approximated a rare piece of meat. Of course, despite the punchy glaze, the meaty taste wasn’t quite there, and a distinctly familiar, not entirely appealing end-of-picnic smell of hot watermelon lingered in the air.
The experiment definitely took the dehydrator into new territory—an utterly unfamiliar and entertaining frontier of texture. It made me wish I had more free time to play around. Time, by the way, being something you need in spades if you’re planning to try out fan-driven dehydrators. Though none were especially labor-intensive, each project took several hours of monitoring at the minimum. If I weren’t juggling a hectic summer schedule of kid-wrangling, moving house, and crashing deadlines, I would have tried again to make a really flavorful wafer (like those carrot tuiles Chris Young mentioned), maybe an airy meringue or two, and I would also have made a few batches of half-dried tomatoes, which develop a chewy, extra-sweet quality in the dehydrator.
Despite the potential fun to be had, a large, effective dehydrator like the one I tried is a serious investment of not just time, but cash and counter real estate. You probably won’t make watermelon meat in great quantity, so the relative value of an at-home dehydrator depends entirely on your snack habits. If you’re a jerky and trail mix connoisseur, then by all means, get one. You can customize to your own exacting standards, and end up with a better product than what you’d buy at the store. For the rest of us chip and pretzel eaters, Trader Joe’s capaciously stocked dried fruit aisle may be enough.