I guess this is the place to report on a pleasant summer alternative.

Found a box of 'House' brand Mugi cha (House foods corporation 6-3 Kioi-cho, Chiyoda-ku, Tokyo - 2.09GBP 16 tea bags - this brand includes some rye in their cold drink formula - US version here)

Each bag makes up nearly 1.5 litres of barley tea.

You just drop a bag into cold water, put it in the fridge and half an hour to an hour later you have a refreshing jug of mugicha (very similar to the Alicantinian classic, Agua de Cebada - but without the sugar)

According to this Spanish link it contains soluble fibre and proteins, calcium, phosphorus and potassium. Also good for your heart and good for steadying your nerves, and recommended for convalescents, children and expectant mothers.

I still like sencha better, but MrLapLap is a mugi fan and I've developed a taste for this unsugared non-slushy variety of barley drink. The ease of preparation is definitely a plus (it's actually ready in 10-15 minutes if the water is already cold)

Thanks again to QShoeGuy and valve bouncer for your kindness :-::-::-: