A tub of Tartaric Acid by Handcraft Supplies. Tartaric acid is an organic acid in crystal form that occurs naturally in many fruits, including grapes. Handcraft Supplies Tartaric Acid can be added to juice, homemade wine or cider to achieve target acidity. Instructions for use are included on the label. The 50g of Tartaric Acid is sealed in a tamper proof and resealable tub.