Rinse the pearl barley at least twice and drain the water. In a saucepan, add the cereal and 4 cups of water and simmer it over medium heat for 30 minutes or until the liquid reduces to half in quantity.
Filter out the water, and you will get about 2 to 2.5 cups of barley water and allow it to cool.
When barley water is cooled down, add the lemon juice, sugar, ground pepper, and black salt. Mix until the sugar dissolves.
Refrigerate and serve cold. You can add ice-cubes also.
As mentioned in the post, you can use regular salt and cumin powder or chaat masala instead of black salt.
There is no set recipe for the lemonade; you can adjust the sugar, salt, and spice according to your preference.
If you feel the barley water too, concentrated, then do not let the water to reduce in half the measure. Just simmer the barley until it comes to a rolling boil. Then turn off the heat and strain the water. Depending upon the barley water measure, adjust the lemonade condiments. The above quantity is for two cups of barley water.