Refrigerate kale in an open or perforated plastic bag for 3-5 days. Flavor becomes stronger and more bitter as kale is stored.
Wash kale just before using. Storing it wet can speed spoilage.
Fill a large bowl with cool water and swish loose leaves around.
Let the leaves sit in the water to allow the dirt to settle.
Lift the leaves from the water. Drain and rinse bowl.
Repeat these steps until there is no grit on the bottom of the bowl.
Pat leaves dry if needed.
For best quality, kale is blanched (cooked briefly) before freezing. Use within 1 year.