Harvest the berries once they change from pink to purple or deep red. Light-colored berries aren't fully matured.
Hold a bowl beneath a bunch of ripe berries. Pull the bunch of berries through the open fingers of your other hand, raking the ripe berries from the bush and into the bowl.
Fill the bowl with cold water once you finish harvesting. Swirl the water and berries around the bowl two or three times so any stems or shriveled berries float to the surface of the water.
Skim the stems and plant debris from the surface of the water with a ladle. Drain the water from the cleaned berries in a colander.