Dilute 200 ml of concentrated juice with water and season with sugar. Bring the juice to the boil and add the semolina while constantly stirring. Boil on low heat for about 10–15 minutes, until the semolina has expanded. The porridge must be rather liquid, like a soup, for making a mousse. Let it cool down a little and whisk into a fluffy foam with a mixer. Serve with cold milk and berries.