Truth to be told, I love onion powder, and it’s one of my favorite homemade seasonings that I love to add to my recipes. Learn how to prepare onion powder using a dehydrator, oven, or air drying. It is a great way to preserve onions so you can make any dish delicious and savory. 

It is no secret that we all love dehydrating things, since you can preserve so much food by doing it! You can easily turn your excess onions into powder during onion season for long-term usage and storage. For this how-to and any of your other drying needs, try this COSORI Food Dehydrator.

Making your own onion powder from scratch will prove that there is no need to buy pre-packaged onion powder from the grocery store ever again. This method is so quick and easy! This post will help you to walk through the process of preparing onion powder. 

Also see How To Make Almond Flour, Tapioca Starch, Dried Onion Slices.

How to make onion powder?

The hardest yet easiest part of this recipe is chopping the onions, and that’s if you do it by hand. If you have a food processor, then forget about doing it by hand. When using a food processor, this process is beyond simple as it practically makes itself. 

As always, when you are drying foods and herbs, a food dehydrator will be perfect. You can also even do it in the oven by putting all the chopped onions in the baking sheets. You can wait for it to dehydrate while doing other chores. 

However, I do prefer using a dehydrator, and it’s a great purchase if you are planning on doing lots of drying. The good part of using a dehydrator is you can have a much more controlled drying environment. You do not need to check the onions often while they are dehydrated. They are way less likely to be burned.

Why make homemade onion powder?

I know you think that onion powder is so cheap, and why should you bother making your own? Well, homemade onion powder is much better in every way! About the store-bought ones, who knows how long it’s been since it has been sitting on the shelves!

Have you ever read those ingredients of store-bought onion powder? You can see there is always a strange “anti-caking agent” on the label. You do not need that to prepare an onion powder. There is only one ingredient required to prepare onion powder and it’s onion!

Once you start to prepare your own, you will never want to use the weird crumble chalk from the grocery shop again!

What kind of onion for onion powder?

I am happy to say that you only need one item to prepare the recipe and its onions! You only need to have fresh onions to prepare the onion powder. I have used yellow onions for this recipe, but you can use any type of onion. Just keep in mind that the flavors will slightly vary. 

Onion powder benefits:

Though all kinds of vegetables are good for our health, certain kinds are available that offer unique beneficial points. Onions have various essential vitamins, minerals, and potent plant compounds, which can promote our health in many ways.  

In fact, the medical properties of onions have been recognized since ancient times, and they are used to prepare delicious meals to treat ailments like headaches, mouth sores, and heart issues. 

Onion powder is prepared from fresh dehydrated onions that have a good balance and flavors of onions. However, you can see some potential beneficial points below. 

  • Treats Infections: Onion powder has antibacterial, antiseptic, and antimicrobial properties making them an ideal choice of spice to add to dishes. 
  • Boost Immunity: The bioactive components of onion powder can power up our immunity level, prevent bacterial infestation, and aid our body in preventing various unwanted bacterial and fungal infections.
  • Treats Cough and Cold: It is naturally high in vitamin C, which can treat common cold, cough, and flu issues. 
  • Prevents the Risk of Cancer: Onions may be beneficial in treating cancer, and they can boost fight cancer-building cells, including stomach and colorectal cancer.
  • Manage Diabetes: The potential properties of onion powder can reduce the blood sugar level. 
  • Promotes Bone Health: It has an excellent source of calcium which can promote bone functionality and prevent free radical damage. 
  • Enhance Digestion: Onion powder reduces stomach bloating, flatulence, and abdominal distension. 

Supplies needed:

Preparing the onions:

There are quite a few options for preparing the onions. You can peel the onions, then chop with a knife or mandoline to at least 1/8 inch thickness (3 mm). 

onion processed in food processor

Otherwise, you can grate the onions with a box grater, or use a mortar and pestle. This procedure will help you to get a cup of onion juice which way you can easily drain the excess moisture. However, If you chop the onion with your hand, you will not receive any excess onion juice. 

pounding onion in mortar and pestle

After chopping, grating, or using a food processor (pulse setting) to get onions pureed, it’s time to drain the excess moisture. To drain it, put the onions on a fine mesh strainer and press the onions gently with a large spoon to get rid of the juice. 

Draining excess onion juice

How to dry onions in a dehydrator?

Lay the grated or sliced onions on top of the dehydrator trays in a single layer and avoid overlapping them. Start dehydrating the onions at 150ºF or 66ºC for 6 to 8 hours, if the humidity is around 80%. Dehydrate for 4 to 6 hours if the humidity is low until you achieve completely dried powder. 

If you are dehydrating onion slices, then you will notice that the dried onion slices will snap into pieces when they are ready. If the onion slices are pliable, they are not ready yet and need more time. 

How to dry onions in the oven?

Spread the onion pieces or grated onion on top of the parchment-lined baking sheet. Make sure the onion pieces are not touching each other and put them in the oven at the lowest temperature, about 120- 150ºF or 54-66ºC. 

pureed onion

If the oven does not have the lowest temperature, slightly open the oven door with a wooden spoon or something similar to achieve a better airflow and let the inside steam escape to dehydrate the onions properly. Check on the onions frequently and flip them over a couple of times to dry faster.

Take it out from the oven when it snaps or at least has a little bend as it should when you let the dehydrated onions sit for cooling. If they are still very flexible, you probably need to put them back in the oven again for longer.  

Sun drying:

Put the onion slices on a large kitchen cloth or paper towel or paper-lined baking tray and keep them in a well-ventilated area, near the window if possible. 

The best option is to place them in a warmer and sunny spot where there is necessary airflow. Do not do it in colder and humid climates, as it will affect the drying time. Flip the onion pieces a few times to speed up the drying process between dehydrating time. This drying procedure will take a few days to prepare based on the onion thickness, weather, and humidity.  

You will know the onions are well dehydrated once they start to crumble in your hand. 

dehydrated onions

Grinding dried onions

To achieve a tasty onion powder, there are a few options to prepare it. You can use a food processor to grind the onion powder at your desired consistency. For even finer grain, you can use mortar and pestle. 

One more suggestion I have seen people use is a coffee grinder. But I am warning you that if you use a coffee grinder, you may not be able to use it again for other purposes.

If you grind coffee in that grinder, the oils from the coffee will pick up the flavor of onion which is gross to have. Have a separate old coffee grinder that is strictly used for grinding all kinds of herbs.

I prefer to use my trusty Blendtec blender to process my onion powder.

Blending dehydrated onions

How To Use Onion Powder?

Usage of Leftover Onion Juice

After chopping or grating the onion, do not throw away the onion juice. You can add it to many recipes, and it will last in the refrigerator for about two weeks. Use this onion juice to marinade tofu, drizzle on top of potatoes, add it on soups, sauces, or dips, or simply add it to any recipe where you want a little onion flavor. 

Moreover, onion juice is not only for cooking, and you can use it for hair care. So get ready to use the onion, get your onion powder and onion juice ready for varieties usage! 

How to store onion powder?

Store the finished onion powder in an airtight container or tiny mason jar (half-pint or pint-sized depending on how much you prepare). Like other dried spices or herbs, it is ideal for shaking the jar once a day for the first week, so it does not stick or glob together. Moreover, shaking the onion powder will benefit you as it can even out leftover moisture and prevent mold from growing. 

Be sure to label the jar so that you do not make any mistakes with other spices like garlic powder. There is an inexpensive option to detect the jars, which are painters or pieces of masking tape used on recycled jars. These tapes are sticky residue, easily removable but adhere well, which is removed by washing the jar. 

Another way to preserve the onion powder is by adding a few grains of uncooked rice. This method will work like our not-so-strange anti-caking agent. After that, store the prepared onion powder in the kitchen cupboard’s cool, dry space. 

Onion powder has a longer shelf life even if you prepare them at home. Store-bought onion powder will last at least 3 to 4 years, while homemade ones will not meet those standards. Depending on how well it is dried and stored, expect it to stay flavorful for up to a year. Since it is so easy and cheap to prepare, you can make your own batch as often as twice per year. 

Recipe notes and information

  • 1 tablespoon of onion powder contains one medium onion or ¼ cup of minced onion or around ½ cup of chopped onions. 
  • You might think there is not a huge difference between onion powder and onion salt, and honestly they are not too different. Onion salt is a combination of onion powder and sea salt. To make it, use a ratio of 3:1 parts of salt and onion powder. 
  • If you are using a food processor to grind the dried onions into powder, then allow it to sit for a minute or two. Or else, the prepared onion powder will spread everywhere.
  • You can use the onion variety of your preference, although they will affect the flavors in various ways.  

Is onion powder as good as fresh onion?

Onion powder is much easier and quicker to use than fresh onion as 1 cup of fresh onion is equal to 1 tablespoon of onion powder. Similarly, suppose you are using a recipe that calls for 1 tablespoon of onion powder. In that case, you need to substitute it with 3 tablespoons of dried minced onion or 1 cup finely chopped fresh onion.

homemade onion powder

If you are preparing a recipe that calls for onions, but you are out of fresh onions, then use onion powder to get the perfect onion flavor.

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