What are examples of hearty foods

Freeze-drying food


If you want to extend the shelf life of food, you have various options to choose from. In addition to freezing and preserving in jars, freeze-drying is a good solution to ensure that food can be used longer. This method is suitable for both fruity foods such as fruits and berries and savory foods such as meat and vegetables. But how exactly does freeze drying work and what are the advantages?

Freeze drying - what is it anyway?

Freeze drying is one of the drying processes that are used to increase the shelf life of food. Freeze-drying removes almost all of the water from the food. The principle of sublimation is used: Thanks to its special physical properties, frozen water immediately changes from a solid to a gaseous state when it is in a vacuum. In order to preserve fruity or savory foods through freeze-drying, they are first deep-frozen at very low temperatures. A vacuum is then created so that the water contained in the food changes directly from the solid to the gaseous state of aggregation. The water vapor escaping through the sublimation removes thermal energy from the surroundings. Therefore, heat has to be fed back into the cold room. In this way, after freeze-drying, a food is created that is still very similar to its original state, but contains almost no water. As a result, it can now be stored for significantly longer. Freeze-drying can take up to 24 hours, depending on the food in question. It is considered to be the gentlest drying method for food, but it is also very expensive. The process is often used when instant coffee is to be produced. But berries and other types of fruit are also sold freeze-dried in stores.

Advantages of freeze drying

In principle, food can also be dried in a much simpler way, such as drying with hot air or directly in the fresh air. These drying options are much simpler and use less energy. Usually, many dried foods such as dried fruit or jerky meat are also produced using simpler processes. However, other drying methods have one disadvantage: they change the food considerably. This is especially true for the structure, because the fruit and the meat literally shrink together. But the taste also changes, because the flavoring substances in the food react with the oxygen in the air. The heat also destroys the vitamins. During freeze-drying, the frozen food is rigid and cannot change its structure. The dried cell components are retained as a shell and can later absorb water again. Since hardly any reactions take place at the molecular level during freeze-drying because there is no ambient air and the temperature is very low, the flavoring substances are almost completely retained. So it is due to the multitude of advantages that freeze-drying is a very popular drying method for food despite the higher effort:

  • The drying process is very gentle because the drying temperatures are low
  • The structure of the food is well preserved
  • The shelf life of freeze-dried foods is very long
  • The quality is higher than that of foods that have been preserved using other drying methods

The biggest advantage of freeze drying is clearly that the food is dried in a very gentle way. Therefore, not only is the structure almost completely preserved, the vitamins are hardly destroyed either. Freeze-drying can significantly extend the shelf life of food. After drying, the food can usually be stored for several years. In terms of quality, freeze-dried foods therefore differ significantly from products that have been treated using other drying processes.

Freeze drying also has disadvantages

Of course, freeze drying also has a few disadvantages that should not be left unmentioned. For example, the process consumes a lot of energy. It also takes significantly more time than other drying methods. The equipment required for freeze drying is relatively expensive. Smaller freeze-drying devices are available in stores for private use, but the acquisition costs are also very high. Real freeze drying is hardly feasible for private households for financial reasons. However, private individuals or companies have the option of freeze drying with Paradise Fruits. Paradiesfrucht GmbH makes it possible to try out your own recipes in the modern test facilities. Raw materials can also be processed in the company's contract drying systems. Small batches are realized as well as extensive production volumes.

Which foods are suitable for freeze drying?

Not all foods are equally suitable for freeze-drying. Foods that contain a lot of water are best. This applies, for example, to fruits such as bananas, apples, grapes or berries. Vegetables such as potatoes, parsnips, carrots and sweet potatoes can also be preserved through freeze-drying. The process is also used for hearty foods: cooked meat, cheese and even entire meals can be freeze-dried. Grain products such as bread, biscuits or cakes are not suitable.