I learned a ton of kitchen skills when I was a prep cook at a from-scratch restaurant in Providence, Rhode Island. Before entering a commercial kitchen, I’d never broken down a chicken in my life; after my time there, I relished the act (yes, I realize that's a little weird, but it was so satisfying!). Other techniques I learned included how to whip up mayonnaise with an immersion blender, ferment pickles, make hot sauce, and sous vide carrot strips in carrot juice—the works. 

But one thing that really struck me was the restaurant's frequent use of a big, boxy dehydrator. While at home most food scraps were destined for the compost bin, at the restaurant, a good bit of what I had always considered future dirt was saved and dehydrated. The sous chef, Benjamin Stroud, would dehydrate leek tops and even mushroom stems, and once they got nice and papery, we’d blitz them in a powerful Vitamix blender to make powders for seasoning all kinds of dishes.

“When I was working as sous chef at Bayberry Beer Hall in Providence, I was tasked with building a pantry for the kitchen to use, and a dehydrator was one of my primary tools for that,” says Stroud, who currently works as the prep cook (and unofficial pastry chef) at the Eddy bar in Providence. “We dehydrated so many things that our spice shelf was overflowing with powders of different colors. Leek tops became a great substitute for onion powder when you wanted something a little more herbaceous. Fennel fronds became a beautiful dust that could go on a plate as a colorful base for steak tartare or be folded into pasta dough. Woody and otherwise unappetizing mushroom stems, instead of going in the compost, became something we could use to up the umami in a dish.” 

It was the ultimate form of reducing food waste—and it’s also something you can do at home.

A dehydrator works by blowing warm, dry air over foods, slowly removing moisture and drying them out. 

“A dehydrator is a great tool for any cook, as long as you have some space to dedicate and a little patience,” Stroud says. “Dehydrators can run at temperatures much lower than your oven is able to, and with a constant fan they can dry things without ‘cooking’ them, allowing you to preserve color and flavor.” 

They are often made up of multiple trays you can layer with foods and then stack or slide together before you start the machine. 

“Dehydrators are typically very easy to use: load the trays with whatever you’re drying, set the temperature, and wait,” Stroud says. For best results, he recommends only dehydrating one type of thing at a time, since different ingredients require varying temperatures (e.g., herbs are better dried at lower temperatures, while meats need higher temperatures for food-safety purposes). 

Another reason to separate your leek tops from your potato peels is that, as Stroud explains, “aromas tend to marry.” You don’t want your chives tasting like mushrooms (or maybe, you do). 

He also recommends spacing things out on your trays, since cramming them together will impede airflow, and “things might get gross instead of dried.”

While it might seem like a fancy restaurant thing to dehydrate, say, smoked onions to season pastrami carrots (which Stroud has done), dehydrating has its practical, waste-saving (and space-saving) applications at home, too. 

“Waste minimization has always been a big part of my cooking career, and dehydrators can help not only reduce waste but also space,” Stroud says. “How often have you bought a bunch of parsley or dill for a recipe and then ended up throwing out the rest? Some people save vegetable scraps in the freezer to throw into stocks, but there are only so many scraps or so much stock a person can store unless you have a massive amount of freezer space.”

So instead of freezing bags upon bags of frozen leek tops, Stroud says to consider the dehydrator.  

“You can toss some of those veggie scraps in the dehydrator and then grind them into a powder. The veggie powder can be used to fortify stocks, season meats, add flavor to sauces or dips...the list goes on and on. Best of all, powders take up a fraction of the space in your pantry, freeing up your freezer space for better things (ice cream).” 

Have some tomatoes that are looking a bit sad? Save them from the compost bin by creating your very own “sun-dried” tomatoes—minus the sun. 

“The best way to do this is to cut them in half and lay them cut side up on the trays, that way you don’t lose any of the juices, and they all get concentrated back into the tomato,” Stroud says. “Keep in mind some tomatoes definitely work better than others; pastier ones like Roma, San Marzano, or, my personal favorite, Canestrino tomatoes, have a lower moisture content so they dry really well.” 

In addition to helping you reduce food waste, there are a variety of other uses for a dehydrator in a home kitchen—which also, admittedly, reduce waste(!). 

“It isn't all just powders,” says Stroud. “You can make your own fruit roll-ups or beef jerky; there's a range of different applications and textures you can achieve. And while not everything is a winner (sometimes you try something and you just get dry trash), sometimes you get something really fun and interesting. For example, dill, garlic, and bay leaves left over from fermenting dill pickles make a funky, herbaceous, and bold spice that you can use on popcorn, potato chips, or you could use to make dill pickle ranch dressing.” 

In short, with a dehydrator, the options are truly endless. 

In our testing of food dehydrators, our favorites were the Samson "Silent" Dehydrator, and the larger-capacity Excalibur 9-Tray Electric Food Dehydrator, which is the brand Stroud used in the restaurant to make his many powders. You can read more about how we tested food dehydrators and how we picked our winners in our review.

Many food dehydrators have dishwasher-safe trays—but it’s best to check your user manual before you put anything in the dishwasher. If you find out the trays are not dishwasher-safe, the best course of action is to wash them with warm, soapy water, spray them down (if your sink has a spray nozzle), and make sure they are thoroughly dried before using. 

As we mentioned, a food dehydrator is a great way to mitigate food waste. You can use it to dehydrate all manner of food scraps—leek tops, potato peels, mushroom bottoms, parsley stems—to create seasoning powders for amping up the flavor of your cooking. You can also use a food dehydrator to preserve ingredients that are on their way out (for example, you can make sundried tomatoes) or to make snacks like fruit leather or jerky. 

Yes, you can dehydrate food in an air fryer. To do so, just set it on the lowest setting (some air fryers also have a dehydrate function) and let it run for a few hours. However, while you can use an air fryer to dehydrate, the results might not be as good as those from a dedicated dehydrator.