Gelatine is a thickening agent made from either collagen (a protein found in animal connective tissue and bone) or algae (known as agar-agar).
Also known by its Japanese name Kanten, Agar is derived from Gracilaria (Gelidium species) a bright red sea vegetable (Gleidium purpurascens)Agar agar has stronger setting properties and, unlike gelatin which requires refrigeration to set, it will set at room temperature after about an hour. The gelling ability of agar agar is affected by the acidity or alkalinity of the ingredients it is mixed with. More acidic foods, such as citrus fruits and strawberries, may require higher amounts of agar agar. Some ingredients will not set with it at all such as: kiwi fruit (too acidic), pineapple, fresh figs, paw paws, papaya, mango and peaches, which contain enzymes which break down the gelling ability.For a firm jelly you require approximately 2 teaspoons of powder or 2 Tablespoons of flakes (lower quality) per 1600ml of liquid.