We have come a long way as a society. Nowadays we are able to buy and utilize commodities that not so long ago were kept as a secret and used only by selected groups, like military or astronauts. This is exactly the road that freeze-drying, also known as lyophilisation, took. Did you know that true jumpstart of this process happened in 1950’s? Despite being first documented as an industrial process in 1890, as a method to keep tissues intact for medical purposes, it took so many years to be used as a method of preparing food for soldiers during Cold War and, during the famous space race, it was a focal point of preparations for space travels. And yet nowadays freeze-dried fruits and vegetables are available to buy in so many places, affordable for pretty much anyone! How is that possible? What is so phenomenal in this process? Let me explain.
Dehydration – advanced, yet so simple
Entire process bases on – to put it simply – removing from our product in low temperature. In order to eliminate almost all of the water contained in our fruits or veggies we have to take four simple steps: selection, freezing, sublimation and packaging.
The first step on our journey is a proper selection. Only the best, freshest crops are used for the next steps. We always strive for the highest quality of our products, and to use subpar ingredients would be a grave mistake. After picking the finest ones, we move on to the freezing process. Here comes the intriguing distinction between the scientific and industrial application. Generally speaking, creating larger ice crystals is preferred; that result can be obtained by freezing it slowly, or by cycling the temperature up and down. With food or medical materials, like cells or tissues, crystallizing big chunks of ice may rupture the biological structure of the cells, which may result in poor texture and loss of nutritive content, as well as damaging the sample for medical purposes. That is why we freeze those materials quickly, utilizing temperatures ranging from -50 to -80° C.
The next phase is drying, where the pressure is lowered and the material is gently heated. By reducing the pressure in the vacuum, the ice sublimes – that is, changes from ice straight to water vapor. Instantly after this process, the second session of drying begins, this time at slightly higher temperature. The goal is to remove any remaining water molecules inside. Finally - the packaging. Last step on our journey, where the final product is packaged into special bags and pouches, crafted perfectly to suit those long-lasting treats.
But why do we freeze-dry food at all?
Lyophilisation came a long way as an industrial way of dehydrating food. From being futuristic way to prepare meals for astronauts to feed them in space, it became ubiquitous, mundane even – and yet still as exceptional and amazing as it was before. We offer fruits dehydrated this way especially because of their mixture of convenience and prolonged shelf life. By removing water from the product it becomes very light – it may lose up to 90% of the original weight. Obviously, it allows for easier transportation and storage. In addition to that, the low moisture content inhibits enzymes and microorganisms, which also makes it long lasting. In hermetic packaging, even without refrigeration, those products are fresh and tasty for many years. And yet the most amazing property of this method is that it keeps the nutritional value practically unchanged. While negligible part of them – around 2% - evaporates along with ice during the sublimation step, the rest is kept inside. That means that our freeze-dried fruits do not need any artificial coloring, food enhancers or preservatives. They are still bursting with flavor and are filled to the brim with natural nutrients. Feel free to browse and enjoy our lyophilized treats with your new knowledge of the entire process of freeze-drying.