Onion powder is an essential part of any spice rack. Of course, it’s incredibly useful for when you’re all out of onions, but it also has unique properties of its own.
It’s hard to put your finger on the difference, but suffice to say that onion powder tastes and smells like onion, but not like 'an onion'. In other words, it contains many of the same notes, albeit with more intensity, and acts more as a spice than an aromatic in the traditional sense. In recipes, onion powder can replace fresh onions (approximately 1 tablespoon of powder to every medium onion), augment them, or even be preferred to them in some cases.
The great news is that onion powder is incredibly easy to make at home. That’s even better news when you consider how onions often come in large bags – or large harvests, if you’re growing your own – and you may find it difficult to eat them all before they start to rot. Well, the solution to all that wasted produce can be as simple as drying and powdering the onions you don’t expect to finish.
All it takes is some time, patience, and a few other things you almost certainly have stocked in your kitchen...
What you’ll need
Onions – the more the merrier. You can buy a bag just for making the powder or simply use any from a batch you don’t think you’ll be able to finish before the start to turn.
Food dehydrator or oven – a dehydrator is better, but there’s no need to fret if you don’t have one. A standard oven will work just fine, albeit with a little extra care.
Food processor or blender – you can also use a good coffee grinder.
Airtight containers – for storage, of course. Mason jars are perfect.
What kind of onions should I use?
You can use any type of onion for onion powder. Red, yellow, white, or even spring onions. They all work, and each will bring its own unique properties to the flavour (and colour) of your powder. For instance, red onion powder will be sweeter. If you like a well stocked spice shelf, why not make a few different ones? You can even use leeks.
If you’re growing your own onions or buying them from a farmer’s market, it’s possible that the onions will be quite leafy. You can use these leaves in the powder as well, although it’s advisable to use a lower amount of leaves than the actual onion bulbs themselves.
It’s also possible to find onions that have begun to flower. While you can still dry and powder these, they won’t work as well because the core of the onion is likely to have become more rigid.
Making onion powder is easy but does require patience. You’ll want to set aside 12 hours for this, although most of that time will be simply waiting for the onions to dry, occasionally checking the dehydrator or oven.
Let’s get started...
1. Clean and peel your onions
You may not need to wash onions bought from the supermarket, but otherwise make sure to clean them first to ensure soil doesn’t get underneath the skin as you peel them.
2. Slice your onions
Use the sharpest knife at your disposal to slice the onions into rings. The thinner they are, the more quickly they’ll dry. However, that isn’t necessarily preferable if you’re using an oven instead of a dehydrator as they’ll also burn quicker (and you obviously don’t want that to happen).
3. Dry your onions
Whether you’re using a dehydrator or an oven, set the appliance to around 100–110°F (approximately 40°C). You can set it a bit higher if you’re in a rush (or just impatient), but higher heats will start killing off the nutritional properties and antioxidants in the onions.
You’ll also want to spread your onions out flat and avoid them touching as much as possible. Leaving space between your onions will help the water particles escape freely, helping to ensure that the onions are dried more consistently.
Any water remaining in the onions will make them harder to grind into a powder and shorten the time the powder can be stored. You’ll know your onions are sufficiently dried when you can snap them in half without them bending.
They should be crispy but, if using an oven, you’ll need to keep an eye on them as they crisp up to ensure they don’t burn. You can help the process by flipping and stirring the onion rings every half an hour. If some turn crispy quicker than others, simply remove those from the tray and leave the softer ones in the oven for a little longer. (The main benefit of using a dehydrator is the security of knowing that the onions won’t burn. Simply leave them be until they’re all sufficiently dry.)
4. Grind your dry onions
Transfer your crispy onion rings to a food processor and blend them into a fine powder. Then transfer the onion powder into airtight containers and store for up to a year.