To store celery, wrap it tightly in aluminum foil and keep it in the refrigerator. Because foil permits ethylene, the ripening hormone, to escape, it prevents the celery from losing moisture and spoiling. Plastic bags on the other hand trap ethylene. Previously frozen celery is no longer crisp, but is still useful for dishes such as sauces, casseroles, stocks and other hot dishes. If freezing celery without blanching, use the celery within a few months.
If blanching the celery, first chop it into 1-inch pieces. Blanch the stalks for three minutes, and then cool them and pack them into containers or freezer bags. If desired, flash freeze the celery by placing them on a tray lined with parchment paper in the freezer. Once the individual pieces are frozen, transfer them to plastic bags. Flash freezing allows you to use a small amount of celery as desired.
Alternatively, place coarsely chopped celery into muffin tins and freeze. Once the celery chunks are frozen, place them in freezer bags. Then remove a chunk of celery, and let it thaw as it cooks with the hot dish. If desired, saute celery stalks and leaves in olive oil prior to freezing. Consider sauteeing celery along with garlic, onions and parsley. Then puree the mixture in a food processor, and freeze the puree in ice cube trays. Add a cube to sauces, skillet dishes or soups for extra flavor.