Freeze dry some strawberries and you'll be sending them into the culinary equivalent of suspended animation. They might look dry and feel dry to the touch, yet, by simply tearing open the foil outer and popping these fancies into the mouth (thereby re-hydrating them in the process) you'll find that, more often than not, the unappetising-looking blobs explode with flavour and swiftly return to a version of their former selves. All of which makes this authentic all-American astro-snack a technological marvel in its own right. How on earth can this be? Freeze drying is the process that has been applied to astronaut food since the early days when eating the right stuff was as important as having it. It's a fiendishly complex process that can be summarised thus: The strawberries are placed in a vacuum chamber and frozen until the water crystallises.

The air pressure is lowered, forcing air out of the chamber. Next heat is applied, vaporizing the crystallised ice. Finally, a freezing coil traps the vaporised water. This process continues for hours, resulting, over time in perfectly freeze-dried strawbs where the fruit is kept completely intact, minus any moisture. Amazing.