Dehydrating your produce
Written by Cassy
Dehydrating in a great way to store home-grown produce, foraged fruit or market bargains and turn them into a variety of ingredients.
Dried goods can be eaten dry, be rehydrated, or added straight to cooking.
In the UK most people use an electric dehydrator due to our inconsistent weather but if you live somewhere with a good amount of sun, you'll be able to dry produce outside, strung on thread on the washing line or laid out on trays. The colour seems to be preserved better by using an electric dryer but obviously requires power. If you're worried about the electricity usage, you can plug in a power monitor to keep track of it.
An electric dehydrator can be used off-grid with a PV system to make use of the power produced in the summer to reduce winter power requirements from a freezer.
Electric dehydrators consist of a box with shelves, a heating element and a fan. Warm air is circulated through the mesh shelves to dry all the contents evenly although there are still areas which dry quicker so you should rotate and change the order of the shelves during the drying period.
Some electric dehydrators have thermostats so that the temperature can be varied. The instruction manuals should give the temperature recommendations for each model. In general, herbs and flowers are dried at a low temperature to prevent oils being lost and to prevent discolouring. Fruit and veg is done at a slightly higher temperature depending on the robustness of the item e.g. thin kale leaves can be dried at a lower temperature than apple slices. Meat and fish is usually dried at the highest setting available.
The time taken to dry depends on the moisture content of the fresh produce, the size of the pieces, the temperature and the airflow. If you only use the dehydrator during the day, the pieces will absorb moisture at night and so the process will take longer. There are also differences between type of produce e.g. herbs take longer to dry than veg leaves of the same thickness. The moisture content and temperature of the surrounding air also make a difference and it's best to site the dehydrator in a dry, airy location.
Table of some examples of moisture content, drying temps, approximate drying times and power used per 1kg dried material or per leather sheet. Time taken and power used will vary considerably with the amount of material being dried and the way in which the dehydrator is used e.g if the dehydrator is turned off at night.
As drying time depends on the size of pieces to be dried, veg is usually sliced, fruit halved, quartered or sliced and herbs separated into sprigs or leaves. Root veg can be put through one of those gadgets to make spirals, which makes pieces thinner than slicing but thicker than paring with a peeler.
Leathers (fruit and veg) are made by lightly cooking and puréeing then passing through a food mill to get rid of seeds and skins. The purée is poured onto the plastic sheets which sit on top of the shelf mesh. Adding apple or plum to juicier fruit will help them to bind together and frozen fruit can be used as well. For eating as is, dry the leather to a tacky consistency and roll in caster sugar to stop sticking. To rehydrate or to use in cooking, dry till papery to the touch, roll up while still warm and crumble off pieces as needed.
Below left – redcurrant and apple fruit leather, just poured. Below right - dried, rolled fruit leathers.
Fruit with waxy skins can be 'checked' by pouring boiling water over them or by immersing them briefly in hot water, to disrupt the waxy coating and allow quicker drying. Otherwise, currants and small berries dry very hard and are best used powdered.
If you want to check how dry the produce is and how much water it has lost, you can weigh it when fresh and then re-weight once dry. You can work out the moisture content -
Moisture Content % = ((weight of fresh produce - weight of dry produce) divided by weight of wet produce) x 100
Fruit and veg tend to have a moisture content between 80% and 90%, so you'd expect the weight of the dry produce to decrease by that percentage.
However, you quickly get the feel for when produce is dry enough. Fruit becomes rattly, veg is crisp or crunchy and herbs and flowers are crisp. Leather becomes shiny and will hold together in one piece. Test pieces by touch when they have cooled, as warm items appear less dry than they actually are.
Leave the dried items in the dehydrator or in a large sealed plastic box overnight to cool thoroughly then put them into preserving jars, jam jars or boxes with tightly fitting lids the next day. Veg for adding to cooking can be crumbled to reduce the amount of space they take up but aromatic herbs are best left in as large pieces as possible to preserve the flavour.
Ideas to try
Veg for adding to cooking – carrot, beetroot, tomatoes, peppers, chillies, greens (carrot tops, fat hen, cabbage, kale), aubergine, pumpkin, courgette, onions/shallots, garlic (puréed first then used as powder as pieces dry too hard to be easily usable).
Veg for snacks – pumpkin, courgette, cucumber, marrow, kale. Veg can be soaked briefly in a marinade e.g. soy sauce, cider vinegar etc.
Veg for salt substitutes – celery, cucumber.
Veg for stocks – tomato leather, mushroom powder or rehydrated pieces, giant puffball powder.
Herbs for cooking – parsley, coriander, mint, basil, thyme, marjoram, basil etc.
Herbs and flowers for teas – mint, chamomile, elderflower, lemon verbena etc.
Dried fruit – for snacks, in baking, in liqueurs (more flavour than fresh), and use finish off glacé fruits.
Fruit leather – flat pieces to roll while still warm or use a petit fours silicon moulds to make fruit pastils.
Suggestions for specific fruits-
Strawberry – slices, strawberry and mint leather
Apple rings and chips (for muesli)
Lemon – purée whole, dry, then powder and use with hot water to make drinks, in ice-cream, pancake mix, sprinkled onto cereal etc.
Rowan berries – dried, ground and added to bread flour
Currants (black, red, white) and small berries – dried till hard, ground and used to make fruit tea fruit squash
As well as drying home-grown produce, dehydrators can also be used to dry commercial products e.g. baked beans for snacks, or to dry home cooking for convenient meals when you're camping, back-packing or at festivals.
Contributors – Andrea, Mustang, Wildfoodie, Bloke Off The Telly,