Freeze-Dried Ice Cream

This freeze-dried ice cream was commissioned by NASA for the Apollo missions in the 1960s but since its first trip into space it has not made it onto any future missions, as it was found to crumble into really small fragments that could be dangerous for astronauts and their equipment under zero gravity conditions. It is made by freeze-drying a mixture of coconut cream, milk and sugar. This freeze-drying process, otherwise known as lyophilisation, removes all the water from the material in a way that avoids much shrinkage or toughening of the material and retains flavour, smell and nutritional content. The liquid is frozen and then the temperature carefully increased whilst it is under pressure so that the frozen water in the material sublimates directly from a solid into a gas. The resulting light and sugary foam is then coated in edible gelatine to hold the chunk together.

This sample has fractured and absorbed some moisture during its time sitting in the Materials Library and now feels slightly chewy and slightly sticky to the touch, but when fresh, it is a wonderfully crumbly, sweet and powdery foam that produced a peculiar sensation of chalk and toffee on the tongue all at once. As long as this ice cream is sealed to prevent it from hydrating, it can be kept at room temperature for years without spoiling. This is because the reduced water content inhibits the action of enzymes and microorganisms that would normally act to break down the substance.