When it comes to reducing food waste, dehydrating may not be as flashy as preserving or cooking with scraps.
But once you realise what it allows you to do, it doesn't take long to see it as an integral part of minimising your overall carbon footprint in the kitchen. It also lets you be extra creative.
Dehydrating food is simply the act of removing moisture from its cells.
Normally that moisture is involved in the growth of microorganisms like mould and yeast, which speed up decay. By removing it, we're prolonging the life of the food.
Once preserved this way, dried foods can last almost indefinitely.
Unexpected guests? Toss a handful of dried figs, pineapple rings and apricots on a plate with some tasty cheese and crackers and, boom! Fancy platter.
Toddler's taken a single bite out of every piece of fruit in the house? Chop out the chomped bits, stew the rest, spread it out on compostable baking paper to dry and, bam! Waste-free apple roll-ups.
Going camping? Fling some dried veggies and powdered stock at arborio rice, whack it in a jar and, kablammo! Gourmet risotto by the campfire.
Whether you're tapping into your inner witch to mix up a batch of healing herbal tea, or getting inventive with homemade presents by blending your own gin, once you start dehydrating seasonally abundant ingredients, you'll find the pantry a place of endless inspiration.
The basics
There are lots of different ways to dehydrate food, and most of them use easily available equipment.
Whichever method you use, keep the following tips in mind and you'll soon build up your dehydrating skills:
- Cut surfaces allow quicker evaporation. Slices will always dry quicker than a whole item. The smaller the pieces, the quicker they'll dry.
- Ingredients shrink as they dry. Lining trays before drying prevents small pieces getting lost.
- Temperatures will vary, but should never go above 70°C or you'll cook the food instead of drying it.
- The lower the temperature, the longer it takes. Some foods take 24+ hours to dry.
- Low and slow dehydrating conserves better colour, flavour and nutrient content.
- Storage is important. Keep dried ingredients in good airtight containers (jars are brilliant), away from heat and light.
Using a dehydrator
You can find dehydrators at all sorts of price-points, ranging from small round ones for less than $50, to huge industrial rectangular ones. Keep an eye on online marketplaces where you can often nab one second-hand.
Regardless of the type you use, similar principles apply.
It's most cost-effective to run a dehydrator when fully loaded, but avoid over-crowding trays. And keep an eye on trays as you're drying: you may need to switch or rotate them to account for hot spots.
Avoid mixing and matching incompatible ingredients (like garlic and strawberry), as flavours will mingle while drying.
Temperatures vary between units, but a decent guideline is the more fragile the food, the lower you'll set the temperature. Herbs, flowers and leafy greens do best between 30-40°C; fruits or juicy veg at 45-55°C; and more robust foods like root vegetables from 60-70°C.
Using an oven or microwave
Ovens are only suitable if they can drop below 70°C, and it's worth noting that you may need to leave it running for 12–24 hours.
If you can set low enough temperatures, operate on the same principles as a dehydrator. Just make sure to leave the door ajar so moisture can escape.
Alternatively, if you use the oven for daily cooking, place trays into the oven after it's turned off to make the most of the residual heat as it cools.
Just remember to take them out before turning it on the next day!
Microwaves are most suitable for delicate things like herbs, flowers and thinly sliced fruit or veg. Simply place food between paper towel on the turntable, run on medium heat for bursts of 30-60 seconds, and open the door to vent steam between bursts.
Heat from the sun
If you have heating or a wood-stove, use the ambient temperature around the heat source to dry food in baskets, on trays, or even in metal colanders (brilliant for making veggie stock powder).
If you don't have a heater, turn to the sun for the ultimate passive energy source.
Hang loose bunches of herbs or greens in a sunny window, or spread fruit slices on a flat basket or tray on top of the washing line.
Window screens are excellent for drying big batches of fruit or veg outside. Just cover them with light cloth to deter beasties, and prop them up in the hottest spot of your garden for a few days (bring inside at night to avoid damp).
Lastly, my favourite lo-tech method is as easy as laying ingredients on trays, baskets or even just a clean piece of fabric on the dashboard of a car.
Crack the window slightly, park it in the sun for a few hours and come back to passively preserved food.
This is excellent for herbs, flowers and thin-cut produce, but I'd advise against drying onions or chilli this way — unless you're accustomed to tear gas!
Anna is the founder of The Urban Nanna, through which she teaches traditional skills, crafts and methods of living in the modern-day world.
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