Rinse the Barley and Qian Shi with water and discard the water. In a big pot, add in 8 cups of water and soak the Barley and Qian Shi overnight
The next day, cook the Barley and Qian Shi with soaking water. Bring to a boil and then lower the heat to low-medium, to let it gently simmer until the Barley and Qian Shi swollen and soft, about 30 minutes or so. Some people like their Barley really really soft - to the extent of mushy, then you need to cook it longer. I like mine soft but still have some chewiness
Add in the dried longan and rock sugar. Continue to cook until the longan plumps up. Turn off the heat. It can be served hot or cold
If you didn't soak the barley:
Rinse the Barley and Qian Shi with water and discard the water. In a big pot, add in 8 cups of water
Bring to a boil and then lower the heat to low-medium, to let it gently simmer until the Barley and Qian Shi swollen and soft, about 1 hour or longer. It should be soft with some chewiness. Stir in the dried longan, rock sugar and cook until the longan plumps up. Have a taste and adjust the level of sweetness to your preference