How to Dehydrate Onions
Slice onions thinly and dry at 125 to 135F (52 to 57C) until brittle, usually 6 to 12 hours. Dry them somewhere ventilated (the smell is strong), then store airtight as flakes or grind into onion powder.
Dried onions are one of the handiest pantry staples you can make, flakes for cooking or powder for seasoning, from a glut of onions. They dry easily, with just one warning: the smell.
Prep
Peel and slice onions thinly and evenly, no blanching needed. Thin, uniform slices dry fastest and most evenly.
Dry until brittle
Dry at 125–135F (52–57C) until fully brittle, usually 6–12 hours. As a stored vegetable, they must be brittle, not bendy.
Flakes or powder
Cool fully, then store airtight as flakes, or grind into onion powder in a spice grinder. Powder can cake, so keep it very dry. See how to dehydrate garlic, shelf life, and the best dehydrators.
Frequently asked questions
Do onions need blanching before drying?
No. Onions dry well without blanching, slice thin and dry until brittle. That makes them one of the easiest vegetables to dehydrate.
How do I make onion powder?
Dry onions until fully brittle, then grind them in a spice grinder to a powder. Store airtight; it can cake, so add a desiccant or shake before use.