Introduction to Food dehydration

Overview of food dehydration

Food dehydration has been around for a long time and has been used by many different civilisations to preserve food. It essentially reduces the water content of food by using air warmed to low temperatures. The reduction in the foods moisture content means that moulds, yeasts and spores cannot grow on the food and spoil it.

Dehydration has the great advantage of preserving the essential nutritional values of the food including enzymes that help our bodies have a feeling of great energy and vitality. It can be used as an alternative to freezing or in combination with freezing to further expand the time a food can be preserved for.

Dehydrating Food Benefits

• Preserve food so that is can be consumed at a later date when it would normally have perished and be inedible.
• Preserve the essential nutritional content of the food such as enzymes and proteins
• Reduce the weight of food - dehydrated foods are often used when hiking
• Foods have wonderfully concentrated flavour
• Create your own tasty, super healthy snacks at a much lower cost than health shop alternatives
• Modern kitchen tools make it very easy and safe to create your own dehydrated food snacks
• After dehydration food weights less so can be carried more easily
• After dehydration no energy is used for storing the food e.g. as opposed to freezing

What kinds of food can I dehydrate?

• Fruits
• Vegetables
• Meats (usually minced) often known as jerky
• Nuts and seeds
• Herbs
• Fish

Rate of dehydration

The rate of food dehydration is effected by a number of factors:

• Temperature - the higher the temperature the quicker the dehydration. However care must be taken not to use too high a temperature as this can cook the food which results in a hard outside and soft inside which will enable moulds to form spoiling the food.
• Air humidity - the lower the humidity of the air, the quicker the dehydration process will be as air moves from the food into the air
• Air circulation - the higher the rate of air circulation, the quicker the dehydration process will be. This is because moist air will be moved away from the food and dry air that takes its place will be more able to take on the moisture from the food.
• The moisture content of the food, the higher the moisture content the longer the dehydration will take

How can I dehydrate food?

A food dehydrator is the tool of choice for dehydrating foods. It is essentially a cabinet that houses a number of trays on which you place your food that you want dehydrating. The cabinet has a heating element inside it along with a fan that disperses the warm air around the trays in the cabinet so that the food on the trays is dehydrated evenly.

The temperature of the circulated air in the cabinet is set so that the food is dehydrated, not cooked. Cooking food denatures the protein structures and destroys enzymes contained in the food. By using lower temperatures for a long period of time dehydrators preserve the enzymes and other important nutrients in your food.

There are many different models of food dehydrator that have different characteristics and features. These features can affect the ease of use, quality of results obtained, ease of cleaning etc. To find out more about what features you may require read our guide on choosing a dehydrator.

Alternatives to using a food dehydrator are using the sun (e.g. sun dried tomatoes) or using an oven (with the door open to allow air circulation). However these methods are much more prone to error, much less convenient and more time consuming due to an inability to control the temperature and air circulation accurately and the limited shelf space of an oven.