dehydrate onions

Buying onions in bulk or harvesting them from your garden, and then dehydrating them is a great way to save money. Dehydrated onions are shelf stable, and are fantastic way to add flavor to soups, stews, stir fries and more. When you are ready to use them, simply rehydrate them and enjoy the delicious flavor they add to your food. 

In this article, I’ll provide step-by-step instructions for dehydrating onions. I’ll also give you tips for storing and using dehydrated onions. As an added bonus, I provide step-by-step instructions for making dehydrated caramelized onions and using powdered caramelized onions to make a delicious dip.

This article includes affiliate links.

Choosing the Best Onions for Dehydrating 

The great news is you can dehydrate any type of onion.

However, as you’ll see below, there is a different process for dehydrating different types of onions, as well as different dryness tests. 

Pros and Cons of Dehydrating Red Onions and Green Onions

While you can dehydrate any type of onion, my two least favorite types of onions to dehydrate are green onions and red onions.

Dehydrating Red Onions

First, let’s look at dehydrating red onions. Red onions dehydrate very well, But I personally prefer to eat red onions raw, either in a salad or on a sandwich. While you can sauté red onions or use them in a soup, the best all-purpose onions for cooking are yellow and white onions.

Having said that, since you can sauté red onions, and since it’s better to dehydrate red onions than have them go to waste, if you have an abundance of red onions, by all means, feel free to dehydrate them.

Pro Tip: Pickling is my favorite way to preserve red onions. Check out my article, Water Bath Canning Pickled Onions in the Nesco Smart Canner.

Dehydrating Green Onions

Personally, I’m also not a big fan of dehydrating green onions. The reason is that I most often enjoy the crispness of green onions in a salad, or as a baked potato topping. Unfortunately, in the process of dehydrating green onions, they lose their crispness, and the crispness doesn’t return when rehydrating.

Having said that, dehydrated green onions still make a nice soup garnish because they add flavor and taste, and I don’t really miss the crispness in soup. By all means, if you have an abundance of green onions either through your garden or because you got them on sale, go ahead and dehydrate them to use as a soup or stir fry garnish.

Now that you know the pros and cons of dehydrating different types of onions, let’s get into the specifics for how to dehydrate onions.

Preparing Red, Yellow and White Onions for Dehydrating 

Start by peeling the onions. I also like to remove the first outer layer of the onion.
I typically coarsely chop onions before dehydrating.

Depending on how you want to use your dehydrated onions, after peeling, you will need to slice or chop them before dehydrating.  

If you are planning to use them in stir fries or onion rings (or any recipe where you want larger onion pieces, simply peel the outer skin and slice the onion into thin rings.  

If you are looking for a more fine-chopped onion, you can peel the skin and chop the onion into small pieces.  Since I like to use fairly large onion pieces in my cooking, I roughly chopped the onions before dehydrating.

For either method, it is important to separate the rings or pieces so that they will dehydrate evenly.  

If your onions are particularly strong, you may want to blanch them before dehydrating. To do so, simply boil the sliced or chopped onions for 15 – 30 seconds, and then immediately place them in ice water.  

Blanching helps to mellow the taste of the onions and prevent them from becoming too chewy when dried.  

Preparing Green Onions and Shallots for Dehydrating 

The process is slightly different for dehydrating green onions, shallots, etc.  

For green onions and scallions, start by washing them thoroughly to remove any dirt or debris. Trim the root end and cut off any blemishes.  

Then, slice the onions into thin rings or lengthwise strips.  

For shallots, cipollini, and pearl onions, begin by peeling off the skin. Cut the onions into thin slices, and then separate the rings.  

Place the Onions on the Dehydrator Trays 

Spread the onions out on the dehydrator tray. A bit of overlapping is fine, but the thicker the layer of onions, the longer it takes to dehydrate.

Regardless of the type of onions you’re dehydrating, you’ll want to spread them out evenly on your dehydrator trays. 

As is always the case with dehydrating, a single layer is best, but I often dehydrate a lot of onions at a time, and because of that, they end up piled up pretty high sometimes.  

This works fine but takes longer. Also, if you have a thick layer of onions, you may want to spread them out a bit as they shrink during the dehydration process.  

Time and Temperature for Dehydrating Onions 

Set the temperature on your dehydrator to between 125 and 135 degrees Fahrenheit.

Once your onions are prepped, simply place them on your dehydrator trays and set the temperature between 125-135 degrees Fahrenheit.  

Depending on the size and thickness of your onion slices, red, yellow, and white onions should be ready in 8-12 hours.  

Green onions typically take between 6-8 hours to dehydrate.  

Since Onions are Smelly, Dehydrate Outside the First 6 Hours

When dehydrating onions, place the dehydrator outdoors to avoid making your house smell like onions.

If you don’t blanch your onions first, they will likely emit a very strong, pungent smell when dehydrating. Because of that, I put the dehydrator outside for the first 4-6 hours.

Dehydrated Onions after 3 Hours

Above is how the onions looked after 3 hours in the dehydrator. You can see that they were starting to dry some but were still very moist.

Onions after 5.5 Hours in the Dehydrator

Here’s how the onions looked after about 5 1/2 hours in the dehydrator. You can see that the edges look yellow and dry, but the onions are still quite moist at this point.

The good news is, the onion smell wasn’t as strong, and since it was starting to get dark outside, I brought the dehydrator inside.

Dehydrated Onions after 9 Hours

After 9 hours in the dehydrator, the onions were almost completely dry, but since there was a tiny bit of moisture in the onions, I decided to let them finish dehydrating over night while I was sleeping.

As expected, the next morning, the onions were bone dry. After letting them come to room temperature, I put them into a mason jar.

Testing to See if Onions are Fully Dehydrated 

Testing for dryness is an important part of the dehydrating process. After all, you want your onions to be dried completely so that they will store properly and be safe to eat. 

There are different ways to test red, yellow and white onions compared to green onions, shallots, etc. So, we’ll look at each category of onion separately.  

How to Test Red, Yellow and White Onions for Dryness 

Red, yellow and white onions should be dry to the touch and brittle before they are considered fully dehydrated. To test an onion for dryness, simply crush it in your hand. If it crumbles easily, it is ready to be stored.  

If not, continue dehydrating until it reaches the desired level of dryness.  

Pro tip: If you placed more than a single layer of onions on the dehydrator tray, be sure to separate the onion pieces when testing for dryness to make sure there is no moisture with any onion pieces that are stuck together. 

How to Test Green Onions, Shallots, Scallions, and Cipollini for Dryness 

There are a few different ways to test green onions, shallots, scallions, and cipollini for dryness.  

First, you can simply touch the onions. They should be dry and papery to the touch. You should also be able to see that they have shrunk in size and lost much of their moisture. Another way to test for dryness is to try bending the onions.  

They should be flexible, but not too soft or mushy. Finally, you can cut open an onion piece to check its center. The center should be dry and free of any moisture. If it is still slightly moist, then the onion needs more time to dehydrate.  

By following these simple guidelines, you can ensure that your onions are properly dried and ready for storage. 

Yield of Fresh Vs. Dehydrated Onions

8 cups of chopped fresh onions
8 cups of fresh chopped onions equals 2 cups of dehydrated onions.
2 cups of dehydrated onions

I started off with 3 pounds of fresh onions. After I removed the onion skins, cut off the bad spots, and chopped the onions, I ended up with about 8 cups of roughly chopped onions.

After dehydrating the onions, I ended up with about 2 cups of dehydrated onions

Making Onion Powder

The onion powder is darker in color because these were dehydrated and powdered caramelized onions.

It’s super easy to make onion powder with dehydrated onions. You can powder the dehydrated onions in a blender, but I find it easier to use a coffee grinder.

Once I powder the onions, I typically run them through a sieve to make sure they are finely ground. This also helps me to discover any moisture in the dehydrated onions since moisture keeps the onions from powdering completely. As a safety measure, after powdering, I run the onion powder through the dehydrator for another hour or two to make sure the onion powder is completely dry before storing.

Pro Tip: Here is the coffee grinder I use, that’s available on Amazon. It’s best to use a separate coffee grinder for coffee and another one for powdering dehydrated food and spices.

To prevent moisture from seeping into your onion powder, I recommend storing your onion powder in a mason jar. You can also add a desiccant pack to the jar, and either vacuum seal it or use oxygen absorbers. If, like me, you like you vacuum seal dehydrated food in mason jars, be sure to pick up these attachments. (All of the items linked to are available on Amazon.)

Dehydrating Caramelized Onions

Dehydrating caramelized onions is definitely possible, but it requires looking at caramelized onions a bit differently. Here’s why. Typically, when you caramelize onions, you use a lot of butter. And fats such as butter are a no-no when it comes to dehydrating. The reason for this is that fats go rancid, so they don’t store well.

Because of that, when it comes to dehydrating caramelized onions, it’s important to sauté the onions in water, instead of butter.

Check out the images below for step-by-step instructions for dehydrating caramelized onions.

simmering onions in water to make dehydrated caramelized onions.
Simmer 2 cups chopped onions in 1/2 cup water
Continuing frying and stirring the onions even after the water evaporates and until the onions turn brown.
Spread the browned onions on dehydrator trays.
Dehydrate at 135 degrees for 8-12 hours until completely dry and brittle.

Once the caramelized onions are completely dehydrated, you can powder them in a coffee grinder or blender to make caramelized onion powder.

Making Onion Dip with Dehydrated Caramelized Onions

a dip made with dehydrated caramelized onions
Caramelized onion dip is fantastic as a vegetable dip or spread on crackers or bagels.

The whole reason I made dehydrated caramelized onions was to make this dip. The dip is inspired by a recipe in the book, Dehydrated Meals in a Bag, by Tammy Gangloff, (Amazon) but I added a couple of extra ingredients.

Here is my version of the recipe.


  • 4 oz cream cheese – let sit at room temp for about an hour to soften
  • 16 ounces sour cream
  • 2 tablespoons powdered caramelized onion powder
  • 1 Tablespoon beef bouillon granules
  • Optional – 1/2 tablespoon minced dried onions

Blend the softened cream cheese and sour cream together until smooth. Add in the caramelized onion powder, beef bouillon granules, and the dehydrated minced onion flakes.

Refrigerate for at least an hour before serving.

How to Store Dehydrated Onions 

store dehydrated onions in an airtight container such as a mason jar.
I personally like to store most dehydrated food, including onions, in mason jars.

It’s important to store dehydrated onions properly to ensure that they retain their flavor and texture.  

First, allow the onions to cool completely before putting them into an airtight container. Mason jars work well for this purpose.  

Next, condition the dehydrated onions by sealing the jar and letting it sit for at least 24 hours. After this time has elapsed, open the jar and check to see if any moisture has accumulated. If so, the onions are not fully dehydrated and should be returned to the dehydrator for additional drying time.  

Finally, vacuum seal the jars (if desired) and store them in a cool, dry place away from light.  

By following these simple storage tips, you can enjoy your dehydrated onions for months, or even years to come. 

Rehydrating Dehydrated Onions

Depending on how you’re going to use your dehydrated onions, you may or may not need to rehydrate them first. When using dehydrated onions in anything with a lot of liquid such as a soup, or if you’re adding them along with something such as dried beans that require a lot of cooking time, simply add the dehydrated onions without rehydrating.

However, if you’re going to sauté them, it’s best to rehydrate them first. The process of rehydrating dehydrated onions is simple: just soak the dehydrated onions in water for about 10 minutes. Then, drain the water and use the onions as you would any other type of onion.

Keep in mind that you’ll need to use dehydrated onions more sparingly than fresh onions, as they are more concentrated. Depending on how strong of an onion flavor you’re going for, I recommend using 50% to 75% less dehydrated onions compared to fresh.

Additional Tips and Information for Dehydrating Onions 

Here are a few additional tips related to dehydrating onions.

  • When dehydrating, onions have a strong smell. Place the dehydrator outside the first few hours and then finish dehydrating indoors. Also, while blanching onions isn’t essential, if you blanch your onions before dehydrating them, they will have a less strong smell during the dehydration process and will also dehydrate faster. 
  • Due to the strong smell and flavor, dehydrate onions separate from other foods so the other food doesn’t end up tasting like onions. 
  • To keep from crying when chopping onions, place the onions in the freezer for an hour before cutting 
  • Onions with a high sugar content may turn pink when dehydrated. This is nothing to worry about. The pink color goes away when rehydrated and cooked. 

How to Use Dehydrated Onions 

Dehydrated onions are a versatile ingredient that can be used in a variety of recipes. Here are my top 10 ways to use dehydrated onions 

1. In place of fresh onions in any recipe 

2. In homemade soups, stews, and chili 

3. In casseroles or other baked dishes 

4. As a topping for pizza, burgers, or tacos 

5. In homemade salad dressings or dips 

6. In marinades for meat or poultry 

7. As a flavoring for popcorn 

8. To make onion powder 

9. To make onion soup mix 

10. In stir fries 


Now that you know how to dehydrate onions, it’s time to start cooking! By following the simple steps outlined in this article, you can create delicious and healthy meals using your home-dehydrated onions.  

Be sure to experiment with different recipes and flavors and enjoy the convenience of having a pantry full of dehydrated onions. 

If you enjoyed this article, you will also likely enjoy these related food dehydrating articles.

Leave a Reply

Your email address will not be published. Required fields are marked *