Gelatin can be defined as a faintly yellow but almost transparent, odorless, and virtually tasteless glutinous substance. It is obtained by boiling the ligaments, bones, skin, etc., of animals in water. Gelatin forms the basis of jellies—as well as glues and perhaps similar items.
Agar-agar is a jelling agent refined from a lacy, bright red seaweed known as Gleidium pupurascens. It is made by cooking, pressing, and freeze-drying this sea vegetable. Rich in iodine, it is used as an emulsifier, for texture, and as a stabilizer in many commercial foods. Some tout agar-agar as an extraordinary food in several ways:
- It makes a firmer jelly than gelatin.
- It can be used by vegetarians because it contains no animal products (gelatin is made from animal bones or pig skin).
- It will jell without refrigeration at 88° F., approximately the temperature of warm tap water.
- It will melt if heated but will become firm again after cooling.