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Usually the key question – freeze-dried or sun-dried? Which of the two loses less nutrition? Which is cheaper? Which tastes better? – is a tangle of diminishing returns, because most of us simply aren’t sure what’s going on in scientific terms when it comes to each method. We thought we’d settle the question from a scientific point of view and come up with some answers.

Introduction to Food Preservation

Since the beginning of civilisation, salting, smoking, curing and even drying foodstuffs have been used to preserve us for longer than we could possibly survive on only fresh food, and modern methods such as freeze-drying, dehydrating, vacuum drying and even canning relied on these earlier innovations.

The Science of Dehydration

Food undergoing the process of dehydration in a dryer has the water removed, which inhibits bacterial, yeast and mould growth.

The Dehydration Process

When food is dehydrated, a constant flow of heat, undisturbed except by smooth changes, comes in from the outside. This heat inside the food in turn flows to water inside the food, which transforms to water vapour and flows to the air surrounding it.

The Benefits of Dehydrated Food

However, being light and compact and long-lasting, things such as dehydrated foods are a wonderful alternative to fresh foods when it comes to backpacking. And all I can add is that intense flavours can be a wonderful surprise!

The Science of Freeze-Drying

Now dried by freezing. First we freeze the food and then the process of drying.

The Freeze-Drying Process

In the water involved in the freeze-drying of our product, going back from ice to water vapour, the water does not go through the liquid phase. The water goes from ice directly to water vapour, and this happens in the vacuum chamber.

The Benefits of Freeze-Dried Food

This process led to food that wasn’t just like wholefoods in texture and flavour, but also in its nutritional value. Freeze-dried food retains far more of this value, since the environment is less aggressive on the structure than space is This is why foods that have been freeze-dried have the longest shelf-life and freshest flavours and textures of all dried foods.

Comparing Dehydrated and Freeze-Dried Foods

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