Drying Onions to Make Onion Powder Using a Convection Oven

Why do you want to dry onions?

I want share how easy and tasty it is to dry your own onions. We dried our first Spanish and yellow onions this summer for soups and to make onion powder for cooking. You can also dry chopped green or spring onions as well for dips, soups or baked potatoes. We have a Jenn air convection oven, that we dry many of the herbs from our raised bed vegetable garden. There may be a point where we get a high quality stainless steel dehydrator to shorten drying times even more.

The dried onions are very flavourful, aromatic and sweet- tasting. Bought onion powder is often bulked up with salt and antioxidents to preserve the onion. This makes the onion harder to digest so you get to keep the aroma in your body longer. By taking the time to dry your own onions, you can have your own real tasty convenient onion powder to last all winter through, and it remains flavourful for a couple of years.

If you are growing your own onions, or buying local organic veggies when they are abundant and inexpensive at harvest time, you know sometimes the veggies don’t keep all the way through the year and are wasted after you spent good money on them. Onions can last a while, but you have to keep an eye on them and they can be quite nasty to come across when they have gone bad! We freeze and can many types of vegetables to preserve them, but putting onions in the freezer is asking for the frozen food to pick up some of the aroma! Dried onions are instantly ready for use with no thawing, chopping, cutting or stinging watering eyes.

Onion drying tips

  • Dry onions that are odd shapes and sizes that won’t store well. Bull-necked onions have a very wide neck and don’t store well. Onion bulbs that have split into 2 or three or are inconveniently small are great to use up, as well as undersized onions are a nuisance to deal with at mealtimes.
  • It is more economical to fill the whole oven with vegetables and herbs to dry. Try and dry chives, garlic, green onions and other vegetables you expect to use with the onions in case of any flavour transfer.
  • You will need to make sure you have no soft furnishings, or clothing hanging in the kitchen. The onion aroma can cling for days.
  • As soon as your onions are dry, grind or place them into sealed jars so they don’t rehydrate, soften and spoil.

To make dried onions

  1. Slice onions into thin rings 4mm thick or less – thinness is more important than shape as these will likely be ground for powder and will be easily crumbled apart when dried if kept as dried sliced onions.
  2. Line a cookie sheet with tin foil and place a large cooling rack on the foil
  3. Lay out the onions in a single layer on the rack
  4. Set your convection oven to ‘Drying’ at 140 Fahrenheit
  5. Dry until onions are crispy and break up in your fingers – about 3-4 hours, onions dry and shrink quite fast as they have large cells
  6. Store whole in a sealed container (we use sealer jars) as dried onions for dips, soups, casseroles,
  7. If you want powdered onions grind in a pestle and mortar. If it won’t grind up with a heavy pestle, it is not dry enough.

We use onion powder for donairs, making stock, rubbing on roast beef, tasty home grown dips with dried peppers and herbs, and recipes that call for it. Try it sometime, you won’t believe the difference in the flavour.

Drying garlic for garlic powder is just as easy.