Why Dehydrated and Freeze Dried Food Lasts the Longest

If you’re looking for a food items that will last the longest, you should consider dehydrated and freeze dried food. These foods can last for years, making them a good option for long-term storage. In this article, we’ll explain why dehydrated and freeze dried food last so long and give you some tips on how to store it.

What is dehydrated food?

Dehydration is a process that removes the water content from food to prolong its shelf life. This is done by either exposing food to extreme heat or by using a special dehydration machine that gradually removes the water content from the food. The heat method requires you to bake, roast or fry your food before you dehydrate it. The dehydration machine is used to remove water from the food while it is fresh, raw and unprocessed, which preserves the nutrients and enzymes. Foods that are good candidates for dehydration include vegetables, fruits and meats. Dehydration is a good option if you are trying to store food for the medium to long-term.

What is freeze dried food?

Freeze drying is another method of removing water from food. It is a process that uses low temperatures and reduces the surrounding pressure to allow water to evaporate. Once the water has been removed, the food is placed in vacuum machines. A vacuum is created inside the freeze dried machine to remove the remaining moisture. The vacuum process has been proven to preserve the taste, flavour and nutritional value of foods.

Why does dehydrated and freeze dried food last so long?

The removal of water is one of the key factors in food preservation as this limits the growth of bacteria and other microorganisms that cause food to spoil and rot quickly. For example, many breakfast cereals have their moisture content reduced to between 3% – 5%, which essentially allows them to have shelf lives of around 12 months.

The challenge for food manufacturers is not just one relating to moisture extraction however, as to enable foods to last a long time, they need to be able to block moisture from entering back into the food right up until it is consumed.  They address this challenge by using packaging with a moisture barrier – the higher the moisture barrier properties, the longer the likely shelf life.

Dehydrated food typically has approximately 90% of the moisture removed, whilst freeze dried food is considerably higher at around 98-99%.  Therefore freeze dried meals set the benchmark in having the potential to be extremely long lasting food.

Tips for storing dehydrated and freeze dried food

  • Store dehydrated and freeze dried foods in tightly sealed water-resistant containers. The containers will help protect the food from moisture and insects.
  • Store your dehydrated and freeze dried foods in a cool, dark and dry place away from direct sunlight. Make sure that the temperature does not go above 20ºC.
  • Ensure your food is labelled up, so you’re clear what it is and when it was produced.
  • Once a year, open the containers and check to see if the food looks or smells rancid. If it does, discard it and replace it with fresh food.
  • Consider adding moisture absorbers to remove any potential moisture that may migrate into the container. The size of the moisture absorber will be dependent on the size of the container and the amount of food stored within, so you’ll need to do your research.


When it comes to long term storage, freeze dried food is superior to dehydrated food. This is because it is processed at low temperatures, preserving the flavour, nutrients and vitamins in the food. Both dehydrated and freeze dried foods last the longest when stored in water-resistant containers in a cool, dark and dry place. Dehydrated foods are usually cheaper than freeze dried foods due to the difference in the production processes, and in addition, dehydration can be carried out at home using equipment that costs just a few hundred pounds. As a final note, always pay attention to packaging, as the better quality the packaging is, the longer the shelf life is likely to be.