How to Dehydrate Onions for Long-Term Storage

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Learn to dehydrate onions in a safe way that helps you create awesome minced onions for cooking, and allows you to make your own DIY onion powder that is so much better than storebought!

So before we get started, the first question is always this:

Do Onions Smell Up the House?

Yes, yes they do. So you may want to find a way to dehydrate your onions in the garage or outside if the weather is nice. No high humidity and temps above 70°F for the best efficiency.

In our family, I’m even required to process the onions outside if I’m doing a dehydrator full. Then my machine sits on the back porch until dusk until I bring it in to finish overnight and into the next morning. The smell is less obvious by then for our family.

TIP FOR SMELL: You can blanch your onions before dehydrating them. Not only does it help cut down on the oils that smell, it helps drying time go a little faster, as well. You can cut, then blanch for 30 seconds or so, dip into an ice bath and dry, or you can caramelize onions for a richer, deeper flavor, too.

How to Dehydrate Onions

Quick Instructions: Chop or slice onions, dry at 125°F/52° for 10-18 hours.

Equipment Needed:

• Knife or vegetable chopper or food processor
• Cutting board
• Dehydrator mesh or parchment paper
• Dehydrator

Instructions:

1. Wash onions.
2. Cut off the root end and peel away the skins (but save them to make onion broth* or vegetable broth later!)
3. Cut into slices or pieces of your choice. I use a Fullstar Vegetable Chopper for doing in bulk, but a knife is all you need.
4. Place on dehydrator trays – separating the layers for better drying efficiency.
5. Dry at 125°F / 52°C for 10-18 hrs. * (
6. Condition.
7. Store in airtight containers.

* Drying times are variable. Depending on the size of the onion (more moisture and sugar), your home’s humidity, the power of your machine, you could dry in as little as 10-12 hours, or from 15-18 hrs. I tend to push the longer end for drying my onions because I want them as dry as possible.

Geta dehydrating magnet for your machine and you’ll never have to wonder about temperatures again!

* ONION BROTH: I throw it in with some more onions and onion skins, and lots of water, and let it go overnight to create a dark, rich, onion broth. Use to cook grains with, to put into other soups, to use as a means of liquid when water is called for in cooking. It’s good stuff!

When are Dehydrated Onions Done?

Check by cooling a few samples of your onions to room temperature. They should be a little pliable, but dry.

If you blanched first, your onions should snap apart when dry.

Oven Directions:

1. Wash and chop onions as above.
2. Spread onions onto a parchment paper-lined baking sheet. I prefer to put the parchment paper on top of a cooking rack that goes on top of the baking sheet to help stop hot spots.
3. Place into an oven preheated to it’s lowest temperature (below 200F is preferred. The lower the better).
4. Crack the door with a wooden spoon or silicone spatula to help the moisture escape and reduce the temperature.
5. Dry for 3-6 hours until onions are completely and snap once samples are cooled.
6. Condition.
7. Store.

Do I Need to Condition Dried Onions?

Yes, as with all dehydrated foods, conditioning is a vital step in the storage process.

Learn more: Using Dried Onions in creating Mirepoix and The Holy Trinity

How to Store Dried Onions

Store in an airtight container.

Dried onions will generally last two years, but you will likely get much longer storage.

DIY Onion Powder

Creating your own onion powder is as easy as 1. 2. 3.

1. Put your fully dried and conditioned minced onion pieces into a grinder of your choice (a coffee grinder, bullet blender or blender).
2. Pulse until a powder forms.
3. Store in an airtight container. Use the following tips to keep your powder from clumping.

Tips for creating your own powders

• Powder only as much as you need for a month or two. Sometimes, especially with fruit powders and onion powder, natural sugars can make clumping an issue (and there are even more ways to help stop clumping). So only can as much as you need at for a short tie and store the rest whole.
• Use arrowroot powder to help keep onion powder from clumping. I use about 1 tsp per cup of powder, but you may find you need to make other adjustments.
• Dry them again – you can put them back into your dehydrator to dry again before storing if you find that maybe they are clumping more than you are happy with while grinding. I prefer placing the onion on a cookie sheet in preheated oven (lowest temp) that is then turned off, for about 20 minutes.

Dried Onion Conversion

1 small onion equals 1/4 cup of minced dried onion equals about 1.5 tablespoons of onion powder.

Frequently Asked Questions

More Dried Onion Ideas