I knew there must have been some sort of sorcery behind freeze dried fruit when it was the only way my fussy toddler would consume his 5 a day. Fruit averse, he would happily crunch on freeze dried mango and even ask for more – music to my mummy ears!
This, however, is more than hocus pocus. It is a Sciencey magic called Lyophilisation, first deployed by the clever folk at NASA who needed a lightweight, portable, nutrient rich food for its astronauts.
Apart from munching them whole, we also like to add our freeze dried fruit to our breakfast muesli, bake with them and more recently, steep them in hot water like you would a tea and Abracadabra! The fruit rehydrates and you are left with the most gorgeously scented (and coloured!) fruit tea, perfect for any time of day.
Freeze Drying Science 101:
Freeze Drying is a longer method of dehydration and essentially involves freezing the product at ultra-low temperatures (around -40C), lowering the pressure and then removing the solid ice by sublimation (transition from solid to gas, bypassing the liquid phase). The fruit is then dried further through desorption, where any residual water is removed.
The resulting product is nothing short of magic – compared to other dehydrating methods, it conserves the most of the fruit’s actual vitamins and nutrients (over 90% versus 50-60% for other methods). Due to the low processing temperatures and minimal deterioration associated with Freeze Drying, it is a much more expensive process than conventional drying.