Where can we find the origin of such an innovative technique as freeze-drying in the ancient alchemy of Egypt, Persia, China or Greece? It would be logical to think so, but the reality is further away, on the other side of the world.
Let’s start by travelling to South America, to the ancient indigenous cultures of the Andes, to find the Aymara, a pre-Inca tribe that controlled the regions around Lake Titicaca. There, at almost 4,000 metres above sea level, the terrible weather conditions posed a constant challenge to survival.
The diet of the Aymara, primarily based on agricultural products, was based on the potato as one of their most important substances (the same potato that the Spanish would later bring to old Europe). You may not know that the potato generates a toxic substance, solanine, if it is subjected, for example, to excessive exposure to the sun, and can generate severe symptoms of poisoning.
Well, the Aymara discovered how to eliminate these toxins and at the same time preserve the potatoes for long periods of time. For more than 1,500 years they have been preparing a local staple food they call “chuno” with these freeze-dried “potatoes” in a rudimentary but incredibly perfect way.
The ancestral process of freeze-dried “papa“
The “papas” were left outside the Aymara houses all night, so at that altitude they would freeze easily. Later, they were trampled, as is done with grapes in our Mediterranean cultures, and then placed in loose wicker baskets and left in streams for a few weeks (in this way, the wild tubers released up to 97% of their toxins).
After this time, the potatoes were again left on the doorstep of the houses, where they were frozen at night and dried in the sun during the day, squeezed occasionally, and so on until the product managed to evaporate all the water it contained.
In this simple (but ingenious) way, the Aymara used the tools provided by their natural environment: high altitude, low pressure and bright sunshine to do an effective job: the first freeze-drying in history!
From then until now, the basics have remained the same. Freeze-drying involves using low pressure, extreme cold and gentle heat to remove that solid water from the frozen food, without having to melt it first. The result, even then, allowed the Aymara people to obtain food that was edible and storable for up to 20 years.