Half a kilo of pineapple blended with water and ice and strained to take out the fibre. Five minutes for six glasses.
Straining matters more with pineapple than with most fruit, because the fibres are tough and stay stringy however long you blend. A ripe pineapple needs no sugar at all, so taste before adding any. One thing worth knowing: fresh pineapple contains bromelain, an enzyme that breaks down protein, so a pineapple juice made with milk turns bitter within an hour and fresh pineapple will not set in gelatine. Neither is a problem here, where it is blended with water and drunk straight away.