To freeze kale without blanching it, wash and dry the kale thoroughly and then transfer the kale leaves to freezer bags. Use the frozen kale in smoothies or soups within four to six weeks.
It is not necessary to blanch kale before freezing it. However, when you skip the blanching step, the enzymes present in kale that cause it to ripen continue to develop. As a result, such kale may develop a bitter flavor when frozen.
There are two ways to wash your kale. Soak the leaves in a solution of roughly 1 to 3 tablespoons of vinegar to a gallon of water and then rinse the leaves under cold running water. You may skip the soaking step and just rinse the kale leaves. Dry the leaves in a salad spinner or gather them into a towel, roll up the towel and gently wring out the excess moisture.
Remove the stems and freeze them separately. You can tear the leaves and freeze them or you can make a chiffonade and freeze the ribbons. To do so, divide the leaves into stacks according to their size. Roll each bundle of kale leaves into a small log and slice into quarter-inch rounds.
Separate the ribbons and allow them additional time to dry. Moisture may result in congealed, frozen lumps of kale.