Begin by removing stems and washing your chokecherries.
Combine the chokecherries and water in a large kettle.
Cover and bring to a boil, then simmer for 15 minutes.
Let the cherries cool; then pour them into an old, clean T-shirt or pillowcase set in a large bowl or pan. (This apparatus may then be suspended over the pan for several hours to allow as much of the juice as possible to drip out. It’s ok to help the process along by squeezing the T-shirt or pillowcase. The remains (pits and pulp) can then be thrown away.)
One pound of berries will yield approximately 1 cup of juice.