If you’re brand spanking new to using a dehydrator, it can be tough to decide what to do experiment with first. Personally, I suggest fruit. Dried fruits are the easiest to use and store, great for snacking or for making things like trail mix, granola bars and muesli. They’re light, travel well, and store well for months and in some cases even up to a year.
Fruit is also the easiest thing to begin using your dehydrator with. Many fruits require no special pre-treatment whatsoever and many of the ones that are often pre-treated are simply dipped in a liquid containing ascorbic acid.
What does pre-treatment entail?
There are several forms of pretreatment for fruit, but I’m not going to recommend sulphuring or sulphites. Stick with one of these more natural treatments:
- Ascorbic acid in Fruit Juice – If you’ve ever made fruit salad with a squirt of lemon to prevent apples and pears from browning, well then, principle is the same! You can buy ascorbic acid powder in the canning equipment aisle, but… why? Most of those powders are derived from GMO and inorganic sources. Use natural ascorbic acid in lemon, lime, orange, grape, cranberry or pineapple juice. Then you also have the added benefit of colouring/flavouring. Do a quick dip just to prevent browning without adding much flavor, or soak fruit for 3-5 minutes.
- Honey Dip – Everyone knows honey lasts forever, and sugar has been used as a preservative for hundreds of years. It will add a sweetness that makes some fruits more like store-bought dried fruit. Downsides: added sugar and calories. Mix 1/2 cup sugar into 1 1/2 cup hot water. Cool to lukewarm and add 1/2 cup honey. Soak fruit for 3-5 minutes and drain well before putting on the dryer tray.
- Steam Blanching – Steaming does help reduce browning, but it changes the flavour and texture. Sometimes the change in texture can be good. It makes apples and pears lighter and less chewy, if you’re adverse to that sort of thing. Steam fruit a scant 3-4 minutes in a steamer basket, and rinse immediately with cold water when time’s up. Drain and pat the fruit dry well before dehydrating.
So when to pre-treat, and when do you not have to?
On fruit, pre-treatment is (mostly) an optional step because fruit isn’t as prone to decomposing due to enzyme action. Treatment with ascorbic acid is most frequently done for aesthetic reasons (to prevent browning) although using ascorbic acid in the form of juice does have a side benefit of extending shelf life and providing a tart flavour to some things that you may find are otherwise lacklustre when dried, like apples.
Berry-type fruit that doesn’t need to be cored, like blueberries and grapes, dry better when their skins are cracked. How much better? Depending on conditions, you may find that you save almost a whole day of dehydrating time. To crack the skins of fruit, drop them in boiling water for about 30 seconds, and then transfer them to icy water. You can also peel fruit like peaches and tomatoes this way.
And when is it done?
Unlike with vegetables, the moisture content of dehydrated fruits is considered generally acceptable around 20%. Touch it. It should be dry, but not so dry that it’s brittle. Tear it. It should be leathery but flexible. When you look along the tear, there should be no moisture beading.
Pasteurizing and curing
If your dehydrator is running at a low temperature, you have opted for dehydrating via a solar method, or intend to store for very long-periods, you should pasteurize the fruits of your efforts (ba dum ching). Either bake your dehydrated fruit in a single layer on a tray in the oven at 160F for 30 minutes, or freeze it at 0F (fridge freezers don’t often go this low), for 48 hours.
Fruit that passes the seems-to-be dry test and/or has been pasteurized should be transferred into a container (preferably glass) for curing, if you intend to store it for a length of time. Curing helps balance the moisture levels between irregularly shaped pieces of fruit which may not have all dried the same amount. Place the fruit in your jar and leave it in a dark, cool area. For 5-7 days, examine the jar for signs of condensation. If any moisture forms on the jar, your fruit isn’t dry enough and needs to be returned to the dehydrator. Shake the jar every day to separate the fruit.
The shelf life of your product is affected by many variables, but nothing will decrease your shelf life more than if you don’t store it properly. Light, oxygen, temperature and moisture will all play a key role in determining ultimate storage time.
You want to find a storage area that is cool, dry and dark. Storing 10 degrees F (5.5C) above or below room temperature (~70F/21C) can respectively halve or double, the life of your dried food.
The ideal storage container for your dehydrated goods is sterile, air-tight, and impervious to pests. For shelf-stable items that you intend to use within 6-12 months, you don’t have to be terribly picky–a glass thread-top jar or the pyrex containers with lids are just fine.