from  “A choice selection of Regency Recipes you can now make at home” – published by Arundel Press for the Royal Pavilion Brighton (UK)

Picked up by sister T at the Brighton Royal Pavilion when she interviewed Adrian Joly, interpreter (i.e. very knowledgeable person) for that amazing building.  Worth a detour to Brighton, if only for the magnificent airy kitchen – the king was so proud of it he used to drag his guests in for a tour.  This is a drink that sister B remembers having as a kid, supposed to be very good for you.

BARLEY WATER

juice and grated zest of 2 juicy unwaxed lemons [probably 2 standard lemons here]
100 g. pearl barley [available in any health food shop]
50 g. sugar

Bring to the boil 1 litre of water with the lemon zest.  Add barley, sugar and juice and return to the boil.  Reduce the heat a little and simmer for about 10
minutes.
Take off the heat, leave until cold and strain through a muslin [cheesecloth] lined sieve.  Chill until needed and drink very cold.