How To Dehydrate Onions – Plus the Secret to Getting the Onion Smell Out!

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Dehydrating onions is simple and one of the most practical things to dehydrate, especially if you grow your own onions or get them on sale at a great price. Of course, it makes sense to have them in your food storage too. Canning or freezing onions changes the texture and taste, but dehydrating them then re-hydrating them when you’re ready to cook is like having fresh onions. I can’t tell that they have been dehydrated when I cook with re-hydrated onions. On top of that, they’re super convenient and as I mentioned economical.

How to Dehydrate Onions Step by Step:



Wash and peel your onions.


 Cut your onions in half.


 Then cut them just small enough to fit into a food processor.


 I can usually get about eight pieces out of a big onion.


Place the onions in a food processor.  Pulse them until they are chopped. Do not just let the machine run or you’ll wind up with onion juice.


 Here they are chopped.


Place them on your dehydrating trays. Here I have my non-stick dehydrator sheets on my trays. These sheets come in handy for small pieces that might fall through the trays. You can find them here on Amazon.


 Here is a closer look.


As you might have already guessed, I don’t blanch my onions before I dehydrate them. I also am dehydrating chopped onions, not onion rings. Cutting the onions into rings is a popular way to dehydrate them, but it seems to be a bit more work, and since the only way my family likes cooked onions is chopped, I do what’s easiest. You can blanch onions before you dehydrate them but it is not necessary; however, blanching onions will cut down on the smell of the dehydrating onions which can be quite potent. Instead of blanching I just start the process outside. Here you can see I have seven trays of a nine tray dehydrator filled. I started with a ten-pound bag of onions.


Here you can see I have my Excalibur hooked up and ready to go.


Set the control for vegetable and let it start outside for about five hours. I usually start the dehydrator in the late afternoon then bring it inside to run the rest of night.


This is what the onion looks like dehydrated. The pink color is from the sugar in the onion. I put the onions in the freezer for two weeks to pasteurize them, then store them in Mason jars until needed. To re-hydrate onions place them in a pan and cover with water. Let them sit for about ten minutes. Pour off excess water and saute or brown as you would fresh onions.

Now, you have to clean your dehydrator and try to get the onion smell out! And you’re waiting for me to tell you what the secret is! Right? The truth is it’s a whole other blog post.  So you’ll have to wait a few days. I promise it’s worth waiting for because it’s so simple and easy!

Update: The secret is out! Go here to read all about it!

  • Velma says:

    My onions are really pink after drying, mostly toward the center of the trays.
    I dried them at 135 degrees.
    Are they OK?

    • Jennifer Osuch says:

      Hi Velma,

      Yes, they are fine. They just have a lot of sugar in them. That’s what is making them red.

  • Loupy says:

    Is there any way of dehydrating onion circles? Do I have to make a paste out of them? And…big question…I am allergic to the oil in onions. Does this evaporate the oil out? I can use granulated onions for myself, but my husband loves to cook onions and peppers. I was hoping to dehydrate some for him when I can get them at a good price at Costco. And, has anyone dehydrated red/purple onions? Do they all work the same? Sorry, I am very new at this. We had a new dehydrator and food saver. I want to have some things on hand that we use all the time. Thanks.

    • Jennifer Osuch says:

      Hi Loupy,
      Yes, you can dehydrate onions when you cut them into rings. No, you don’t have to make a paste out of them. Dehydrating them will not remove oil, it removes only the water. Yes, you can dehydrate red and purple onions. Yes, they will dehydrate at the the same tempeture and time.

  • Betty says:

    After you freeze the onions for two weeks, you said you can then put them in mason jars.
    So what is the process , do you let them thaw first? how do you get the moisture out of them before putting in the jars

    • Jennifer Osuch says:

      Hi Betty,

      There should not be any moisture in the jars. There might be condensation on the outside of the jars but not on the inside. If there is condensation on the outside let it evaporate and dry before placing the onions in their room temperature storage container if it is different than the container you froze them in.

  • Jeanne says:

    Hi, I just bought a cheap dehydrator. Didn’t know you have to rotate every 2-4 hours, which I’m not sure how you manage when dehydrating time is 24 hours. So much for how simple the ad said the thing was to use. I love dehydrated onions, and that is why as an impulse I ordered the thing. No mention in manual about the smell, which I have learned about on your website. Don’t want to pay shipping to return it, so I’m going to try it today with onion & zucchini strips, but I’m not going to rotate the trays. I’m pretty lazy.

    • Jennifer Osuch says:

      Hi Jeanne,

      I’m not sure which dehydrator you have, but rotating the trays can be annoying! There are other dehydrators out there that don’t require tray rotation every 2-4 hours, so don’t give up….:)

  • Meri says:

    The only way this could be better is if there were instructions on how to dehydrate all these foods in a regular oven. I don’t have a dehydrator and never learned how to use one… I always use the oven and prefer it. There are quite a few large families out there that can’t affored to run out and buy one… Maybe you might consider them? Other wise… This is great and I love it. Thanks for the trouble you went to to make this info available on the interweb.

    • LindaS says:

      Meri, you don’t have to buy an expensive dehydrator to start. Oven drying is not as controlled and you must take the time to really watch it closely. I started out with an inexpensive dehydrator that I got at Aldi’s for $30.00. It doesn’t have all the “bells & whistles” and it probably takes longer to complete the job, but it works for the things I need. I even saw a small Excalibur one, like the one shown above, at Walmart today for $99.00. It doesn’t have as many trays as the one shown but it is a less expensive alternative.

  • Pallavi Bohra says:

    Very good article. Do have any recipe or reference for osmotic dehydration of fruits. I am looking this for long time.Help share if you have any idea. Thank you

  • Maj says:

    Tried with 3 onions in dehydrator, after about an hour couldn’t take the smell any more. Even kIeenex in the nostrils didn’t help! Live in a small one room apt and the whole place just stunk so bad. I have a box fan, would that help if cranked up to full power for the entire day?

    It’s winter now, so pretty much no way to leave the windows open 🙁

    • Jennifer Osuch says:

      Hi Maj,
      I know dehydrating onions in the winter is hard. I usually do them in the summer outside. If I do dehydrate onions in the winter I usually leave them on downstairs right before I go upstairs to bed. Then as the night goes on and the onions get more and more dry the smell is not so overpowering. I know none of that helps you in a small apartment. No, I don’t think a fan would help. It would probably just circulate the smell….:) You might try dehydrating a smaller amount of onions. Also, you might try dehydrating some potatoes with the onion. But if I were you, I’d wait for a nice day outside and start them outside for a few hours even if you have to bring them inside after that. Like I said, the really overwhelming smell is just right there at the beginning of the dehydrating process.

  • Jennifer says:

    After dehydrating onions the last time, I used a coffee grinder to grind them for powder. After a couple of months in a Mason jar the powder turned into one giant hard clump. I had to scrape it out with a knife. Can I put rice in the jar to keep this from happening? Or do you have another tip or suggestion?

    • Jennifer Osuch says:

      Hi Jennifer,
      Putting rice in the jar to keep your onion powder from caking is a good idea. The thing is that if you live in an area that has a lot of humidity then caking will occur. The trick is to keep the air (because it has moisture in it) away from the powder. The best way to do this is with a vacuum sealer. My next choice would be an oxygen absorber. Then if I didn’t have either of those I might try rice.

      • Ann R says:

        I’ve found that using dry navy beans works well. The rice just came through the holes in the container top, so I had to use a tea strainer to keep the rice grains out of my food. The beans are bigger, so they can’t escape through the holes.

  • Sally K. says:

    I ran out of onion flakes, and this tutorial was very handy for me today. Thank you so much for a thorough method.

  • Frances D. Bruner says:

    Is there a way that I can dry onions in a low oven or by air drying? I don’t have a dehydrator. I have been given some onions and need to do something with them. I know that I can freeze them, but I would rather hve them air dryed so that they can be put in jars and save my freezer space for fresh vegetables that will be in soon (if they are not alredy). Thank you.

    • Jennifer Osuch says:

      You can dry them in the oven at a low temperature. You can try air drying if you live in a dry climate, but you need to make sure you have a fan on them and be vigilant about spotting mold. I honestly, don’t recommend air drying.

  • Teresa Hovland says:

    What do you suggest about removing the odor of onion from plastic dehydrator trays? I just have a small counter top dehydrator that really works great for what it does. Just did a bunch of apples. Was just going to try some onions when I thought hmmm … I wonder if the odor will be forever in the plastic. I am wondering if cookie sheets in the oven would be a better idea and save the plastic for less smelly foods. Hmmm … but then how long would we have to stay at a motel or go on vacation waiting for the smell to dissipate?

    • Jennifer says:

      You could try using potatoes in your dehydrator after you dehydrate the onions to get the smell out. You can dehydrate them in the oven as well. I would just make sure it was on a day you could open the windows….:)

      • Elishia says:

        just remember when dehydrating potatoes to boil them prior to dehydrating them to get all the starch out or they will turn black in your dehydrator

    • Jeannine says:

      I don’t find that the onion smell stays in the plastic tray liners. In fact, after I wash them in hot soapy water, I don’t smell anything at all. I suppose you could always add a tiny bit of bleach. When I can, I also hang mine out on the clothesline for a couple of days.

      I know you can dehydrate in the oven, but I’ve found that it just doesn’t work as well.

  • Deb Hendrickson says:

    can you just leave the onions in freezer bags in the freezer and use them like that instead of transferring to mason jars?

  • A mandolin slicer (>$14 for one you will use a few years) makes short work of 5 pounds of onions – seriously, under a minute and you have them all sliced to rings in uniform width!

  • Jeannine says:

    My Excalibur runs day and night for at least 2 months every fall as I dehydrate my onions, garlic, carrots, smoked jalapenños for chipotles and tomatoes. I’ve had it for 11 years and am amazed it keeps working. Jennifer, I found your blog by asking why my dehydrated onions turn pink! Now I know. I do roughly 100 lbs of onions every fall. I grow my own so I know they have never been exposed to pesticides. Have you tried garlic? I grow my own and get roughly 20 lbs of cleaned garlic bulbs every year. I clean the cloves, put in my food processor with a little dry white wine (water would work, but why use water when you can use wine!) and process into a rough paste. Spread on the racks and dehydrate at the vegetable setting. I use a heavy rolling pin on the backs of the plastic tray liners (I use the ones with the holes) to get it off and pulverize into minced garlic. I grind some into garlic powder and just store the rest in Mason jars. Yes, my friends and family love me!

    • Jennifer says:

      Hi Jeannine,

      Sounds like you are busy! Yes, I have tried garlic, but have not dehydrated it with the wine/water. That sounds like a great idea! I’ll have to try it.

  • Doreen says:

    I don’t have a processor. Could I just dice up the onions and dehydrate it that way?

  • Lyn says:

    My dehydrator is new and I have only used it twice so far. I have some apples to do and as luck would have it came across celery really cheap today, so that is being processed right now, which means I keep putting my apples off. I hadn’t given it much thought about the odour of drying onions and as I was thinking of doing some onion and I am so pleased to have come across your blog, so thanks. My question is – would the same thing apply if dehydrating Sweet Potato as ordinary potato? Have you tried it? Not sure whether it would be the starch which would be the secret ingredient in neutralizing the odour or not. Does anyone have any thoughts?

    • Jennifer says:

      No, I have not tried sweet potatoes but they might work. I guess it depends weather you like your sweet potatoes savory or on the sweet side. If you like yours savory then a little hint of onion might be a good thing. I generally like mine sweet so I probably wouldn’t dehydrate sweet potatoes right after onions. But if you try it let me know! Now, I’m curious as to whether it will work….:)

  • Handful says:

    Why do they have to be frozen/ pasteurized?

    • Jennifer says:

      When you dehydrate food you don’t heat the food to a high enough temperature to kill insect eggs or bacteria. Freezing the food in a deep freezer for several weeks takes care of the majority of problems that might arise from bugs and bacteria. It’s not 100% full proof some bacteria freezes just fine and will thaw out and still be active. Obviously the ancient Egyptians did not have freezers but they did live in a very dry climate which is helpful in dehydrating. Since I do not live in a dry climate and I have the freezer option available to me it’s just an extra precaution that I take. In addition I find the freezer continues to dry the food out just a bit and as a result I get food that is very similar to freeze dried.

      • G. says:

        The Excalibur dehydrator guide suggests that onions should be 145 degrees. I wash and soak my fruits and vegetables (I don’t worry about onions) with either vinegar or baking soda wash before processing them for the pressure canner, WBC, freezer, or dehydrator. This should help with surface pesticides, or any other unwanted “stuff” on there. It only helps. Our immune system takes care of the rest, but unfortunately not the pesticides. While the freezer will kill any larvae or worms (think meal moths) in dog food or bird seed, it is not pasteurization. That is why food is blanched before it is put into the freezer…to stop the enzymes from continuing to break down the food until it is frozen. It will taste better. That being said, there are foods, such as blueberries that need no blanching.

        We cannot run or hide from “bugs.” If you buy cookies, or flour from the supermarket, it is tested at the processing plant for **how many** bug parts there are, not *if* there are any. I shiver just thinking about food processed and handled in restaurants.

        Look at it this way. There are more of “them,” (undesirable microbes and creepy crawlies) than us. Don’t forget about the mites that live at the base of our eye lashes. “Those are called Demodex, and they’re mites that live on everyone’s eyelashes. They feed off of the dead skin cells and oil that collect in your follicles.” (11 Everyday Things That Are Terrifying)

  • Dorrie says:

    I rinse with vinegar spray

  • Mike the Gardener says:

    Now that is a very in depth and detailed explanation. Thank you for this article!

    I just purchased my first dehydrator and will definitely be using your advice here.

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