Lemon Barley Water

1. Rinse the barley thoroughly in a sieve under cold running water until the water runs clear.

2. Cover with 1.5 litres of water, bring to the boil and simmer gently for 30 minutes.

3. Meanwhile pare the zest thinly from the lemons – avoid the white pith, which is bitter.

4. Strain the hot barley liquid into a jug and add the lemon zest and sugar straight away.

5. Stir to dissolve the sugar, then leave to cool completely while the zest infuses.

6. Remove the zest, stir in the lemon juice and serve ice cold with a slice of lemon.

Tip: The traditional drink of the Wimbledon championships since 1935. It looks slightly cloudy – that is the barley starch, not a fault. Keeps 3 days in the fridge.