Look for kale with firm, deeply colored leaves and moist hardy stems. Kale should be displayed in a cool environment since warm temperatures will cause it to wilt and will negatively affect its flavor. The leaves should look fresh, be unwilted, and be free from signs of browning, yellowing, and small holes.
Kale should be washed in a sink or tub full of cold water. Submerge the leaves in there and agitate them gently
To store, keep kale refrigerated in an airtight bag. It can typically be stored for up to 5 days, but you may notice the flavor increase in bitterness with longer storage. Only wash the kale when you are ready to use it as washing before storage will promote spoilage.