Rinse raw pearl barley; Soak it in water for 3 hours; Remove and drain it;
Rinse and drain ginger; Slice it;
Fill a stockpot with 2L water; Add the ginger and the pearl barley into the pot; Bring to the boil over a high heat; Turn to a low heat; Cover the pot with its lid; Cook over a low heat for 90 minutes; Turn off the heat; Let the drink stand for 15 minutes to cool a bit;
Rinse and wipe-dry lemons; Bisect the lemons lengthwise with a knife; Slice an half and remove any seeds; Place the remaining halved lemons over the doom of a lemon squeezer and then press and twist to extract the juice;
Remove the ginger slices from the drink from the step 3; Gradually stir the lemon juice into the drink; Slowly stir 3 tbsp honey into the drink; Arrange the drink in serving bowls; Garnish with the lemon slices; Ready to serve.