From preserving and conservation: Drying & Dehydrating

Preserving food to build up sufficient winter stocks – this is no longer a necessity these days. It’s still a lot of fun to preserve fruits and vegetables, especially if they come from your own garden. In addition to making fruity treats like jams and marmalades or juice, syrup and jelly, you can also preserve or freeze food.

Drying and dehydrating are age-old methods, but they’re still super convenient. Let’s take a closer look. Let’s go!

How it works: some dry theory

Preserving food by removing the moisture from it is simple and practical and has therefore long been popular as a preservation method. Hardly any aids are needed, because in principle the sun can also do all the work.

This brings us to the small difference between drying and dehydration. The term drying is more coarse and describes mainly the air drying. The food is cut into thin slices or small pieces and placed in the sun or hung up. The heat of the sun causes the water contained in the food to evaporate – fruit and vegetables first become wrinkled and later crispy.

Drying works the same way, except that some help is given in the drying process. By using an additional heat source such as an oven, a special dehydrator or even a fire, the water evaporates more quickly.

But not only fruits and vegetables can be dried. Smoking is also a form of drying, which is used for fish and meat. Crispbread and rusks are dried and also noodles are dehydrated to make them storable. These are just a few examples – if you take a look in your pantry, you will realize how important this method is: cornflakes, oatmeal, rice, tea… all dried.

The food industry uses a variety of drying methods that are faster and therefore cheaper than the “tried and true methods.” For example, fruit for muesli is usually freeze-dried, as is instant coffee or the little vegetable crumbs in powder for vegetable broth or cup soups. Freeze-drying is quite complicated; the short version: the water it contains does not change from liquid to gas, instead the products are deep-frozen and a special process turns the frozen water directly into gas, without any liquid intermediate stage.

Why all the work? Advantages of drying

Dry foods are less susceptible to being invaded by bacteria and fungi. These, in fact, need sufficient moisture to survive. However, all dried products retain some residual moisture – depending on which drying method was used. Purely air-dried apple rings, for example, usually still contain more water than those that have been dried in a dehydrator or oven. The more moisture that is still present, the greater the risk that the food will mold. They should therefore always be stored in an airtight and moisture-proof container.

Another advantage: you save space. Due to the removal of water, the food shrinks and becomes smaller; it can then be stored in cans, jars or bags. They also lose weight – a bag of apple chips is as light as a feather. At the same time, vitamins, minerals and fiber are largely preserved. The taste does not suffer either, but it usually changes a little. Many fruits taste more intense and sweeter.

From preserving and conservation: Drying & Dehydrating
Ripe tomatoes still taste wonderfully aromatic when dried

Suitable food

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No matter what you want to dry or dehydrate, the food must always be fresh and undamaged. Only then will they taste delicious in the dry state and keep longer.

You should wash off any impurities beforehand, but otherwise refrain from using more water, as the slices and pieces should not become unnecessarily wet. So dry or pat the food well after you’ve washed it.


  • Small berries and grapes are dried whole, you just need to remove the small stems beforehand.
  • Larger but soft fruits like strawberries or apricots are cut in half.
  • Firm fruits like apples and pears can be cut into thin slices. Depending on taste, they can be peeled; in the case of apples, you should remove the core, as it is larger and harder than in a pear.
  • The thicker the slices, the longer the drying process and the softer the fruit will remain. With apples, for example, a distinction is made between softer apple rings and wafer-thin, crispy apple chips.

Vegetables, herbs and mushrooms:

  • Herbs do not need to be chopped beforehand; it is more convenient to chop them afterwards.
  • Tomatoes are very watery on the inside and can be patted a little dry beforehand.
  • Vegetables that are very hard when raw (beet, celery, …) can be cooked very briefly beforehand and then patted dry.
  • Smaller chilies and peperonis can be left whole and thus dry in the air without problems.
  • Legumes such as peas and beans can be dried without the pods.
  • Mushrooms can be dried very well when sliced. Their aroma is preserved and even intensified.

Do-it-yourself drying: Get into the hot air

Now that you’ve gotten the urge to try drying and dehydrating yourself, we’ll introduce you to three methods. There’s bound to be a suitable option for you.

Air drying

Air drying can be done in different ways. Apple rings are traditionally threaded onto strings, as the slices have a hole after the core is removed – super practical! However, the slices or other prepared foods can also be laid out on a support. Perfectly suited are lattice frames, which you can also build yourself relatively inexpensively. The advantage of this is that air can also reach the dried food from below and moisture can escape. But you can also start drying on an oven rack, wooden boards or trays, provided you turn the slices and pieces regularly.

Herbs can be tied in small bunches, and chili peppers are easy to hang.

How long it takes to dry depends on the temperature and how good the ventilation and humidity are. And, of course, whether you want to dry thin slices or thicker pieces. You’ll probably have to do some trial and error to see what works best for you.

But you should definitely pay attention to these points:

  • Humidity must be low. Often temperatures drop at night, even in summer, and there is dew on the plants in the morning: so the humidity has increased. If the weather doesn’t cooperate, you sometimes have to be proactive: bring the food inside if you let it dry outside and continue drying in the oven if necessary. Longer delays will harm the quality, and in the worst case mold will form.
  • Check the food regularly even under good conditions. If mold forms, you must immediately discard the corresponding pieces.
  • Sunny places are of course great, but the food should not be in the blazing sun. UV radiation can cause discoloration and affects the vitamin and mineral content. So treat them to a cover under which it is still airy. Herbs dry best in the dark, otherwise they lose flavor and color.
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Why not get inventive? On hot summer days, there are places that are so warm that it’s almost too bad not to take advantage of this ideal drying climate. Attics and attic rooms can get really warm and even in the car it often gets unbearably hot – good places to make apple chips & co in. But beware: the smell of dried mushrooms can be penetrating and linger undesirably long in the car.

Drying in the oven

This method may seem a bit daunting at first, as the oven runs for several hours and high electricity costs are feared. However, at the low temperatures required for dehydrating, the power consumption does not exceed that of most commercially available dehydrators.

Temperatures around 40 degrees are already sufficient for vitamin-preserving dehydration. On most models, the temperature scale starts at 50 degrees, so you can set a little lower and check the temperature with a thermometer if needed. At such low temperatures, you don’t even need a special oven thermometer.

By the way, often temperatures around 30 degrees are reached just by turning on the lights.

You can use either a rack or a baking tray. Some fruit sticks quite a bit, baking paper is definitely helpful.

To make everything work, here are the most important points:

  • The humidity must be able to escape, so leave the oven door open a small crack. You can use a wooden spoon or spatula to keep the door from closing on its own.
  • Set the oven to circulate air so that the warm air is well distributed and the moist air is removed more effectively.
  • The fruit or vegetable pieces should be moved or turned regularly.
  • Again, the duration depends on how thick the pieces are and how high the water content is.

Drying in a dehydrator

Dehydrators come in many different sizes and price ranges. Simple models you just have to turn on, the temperature is controlled automatically. However, there are also models with more extensive setting options. In the manual of your model you will certainly find time specifications for drying the different foods.

Dehydrators consist of several stackable grids or are constructed like a small cabinet, into which you can slide the grids. Warm air then flows from the bottom to the top, reliably drying fruits, vegetables, herbs and mushrooms.

Some models allow you to insert baking paper. Check to see if the extra layer impedes airflow. The paper is handy because otherwise sugary fruit can quickly stick to the grids and very watery pieces (for example, tomatoes) drip onto deeper layers.

Delicious ideas
Fruit pieces for muesli or porridge

Dried fruit or dried fruit are perfect ingredients for a fruity muesli or porridge. Apples are particularly suitable because they can be dried very easily both in the air (for example, suspended on a string) and in the dehydrator or oven. In addition, they are available almost all year round from regional cultivation. But dried plums, dried apricots or figs are also very popular.

It makes sense to use seasonal produce. For example, in summer you can pick delicious fruits yourself in many places and pay a low price per kilo. Even better, of course, is to harvest fruit from your own garden or balcony. When the harvest is bountiful enough and you’ve had enough of strawberry jam or raspberry syrup, you can dry the fruit and use it as a sweet ingredient.

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Dried fruit can also be soaked overnight in a little water, and it will regain volume and change consistency.

Don’t be surprised if your home-dried fruits look different in color than store-bought products. These are often treated before drying, for example with ascorbic acid (vitamin C) or sulfuric acid, so that they keep their beautiful colors and look more appetizing.

Base for vegetable soups

Commercial broth powders are often full of flavorings, additives and palm oil. But the basis for delicious soups is quickly made by yourself. Choose your favorite vegetables and let them dry well in very fine slices or small pieces. It should dry more than, for example, dried fruit, which you quickly snack away, because the broth powder should also be stored for some time.

Ideal ingredients are carrots, kohlrabi, beet and celeriac. You can dice them very finely or slice them very thinly and dry them directly. For larger pieces and a rather short cooking time of the soup, you should blanch them before drying. Otherwise, raw and still hard vegetable pieces will float in your soup later.

Leeks, onions and celery also add flavor. The rather fine vegetables can be dried raw, as they will cook quickly in the later soup. What else goes into your vegetable broth powder is up to you and your taste: how about zucchini, pumpkin or some chili?

It is also possible to finely chop the dried pieces in a mortar or with a chopper.

Salt mixes with chili, herbs or mushrooms.

This idea is perfect for you if you want to try drying first and don’t want to go big yet. Chilies, herbs and even mushrooms can all be dried easily and without any tools. Chilies and herbs can be hung up in a warm, dry place. For herbs, darkness is also important, otherwise they lose their color and aroma. Mushrooms dry well in thin slices laid out on baking paper; follow the tips for air drying.

There are two ways to do it:

Grind the ingredients first before you mix them with the salt. For example, you can pound them in a mortar and then mix them with coarse sea salt, which looks great.
You can also add the salt first and chop or grind everything together. This makes the salt very fine.

Works just as well: make your own bath salts! Take a look here: Three herbal ideas for cold days.


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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