Tech rundown: Dehydrator
14. Jul, 2010 
5 Comments
Not all the equipment used in avant-garde cooking was invented in the past two decades. Some, like the dehydrator, have essentially been around for centuries, if not millennia.
All cooking can be broken down into a few simple processes. One of them is understanding and controlling water, and that’s exactly what a dehydrator allows you to do. By removing water from food, you extend its shelf life and give it a pleasant, crispy texture. Of course, frying also gives you a crispy texture, but it does so by boiling off the water at very high heat, which causes other chemical changes. A dehydrator slowly evaporates the water with gentle heat, preventing some browning reactions and leaving some enzymes and aromatic molecules unchanged. To some extent, dehydrating is to frying what sous vide is to grilling or roasting.
You don’t have to buy a purpose-built dehydrator: historically, food would have been dried by being placed in any warm spot with good air circulation. Many things can also be dried in a very low oven. For some things, though – especially herbs – an oven simply can’t go low enough, and ovens don’t offer the same degree of control as a dedicated dehydrator.
There are lots of ways for modern cooks to use dehydrators creatively. In some cases, pieces of fruits and vegetables are dried whole and used as dramatic garnishes, like the onion garnish in this dish from Atelier. In other cases, you can work with the ingredients after dehydrating. I once made the dish “Salsify, Smoked Salmon, Dill, Caper” from the Alinea cookbook, which involves coating salsify with lemon zest, red bell pepper, caper, ginger, and red onion that were dehydrated individually, then crushed to a powder and blended. Finally, ingredients can be manipulated first, then dehydrated. For example, you could take a head of garlic, roast it, puree it, then spread the puree out on parchment or acetate and dehydrate it for “roast garlic chips.” Or take any liquid, add methylcellulose, whip it, and dehydrate the result for a “puff” texture.
My dehydrator is probably the one “avant-garde” piece of kitchen equipment that I use most often for pedestrian applications, like the dried sour cherries in the photos here, which will go into fruitcake for Christmas. One of my favourite uses for a dehydrator, though, is fruit leather. Take some applesauce, add some other fruit puree if you like (I especially like blackcurrants), spread it evenly on a fruit roll sheet, and dehydrate until it’s no longer tacky. It never lasts more than a couple of days in my house!
Do you use a dehydrator in your kitchen? What for?
Matthew Kayahara
I made onion powder the other day. Here is the video I made
http://www.youtube.com/watch?v=OJkHdGHqhNM
Jerky and fruit leather. Two easy to make foods that taste great and are good for you.
I have a dehydrator, but haven’t used it in a while. Once upon a time, I dried all kinds of fruits and made applesauce leather. I also made beef jerky. I really should get back to this; thanks for reminding me!
@Alan: Great video; thanks for sharing. Favourite uses for onion powder?
@”dehydrator” and Melissa: I keep meaning to make beef jerky, but somehow I’ve never gotten around to it. I need to give this a try!