Agar-agar, sometimes referred to as China grass, kanten, or just agar, is a gelatinous polysaccharide derived from red algae. Agar is used to gel many food products, such as puddings, desserts, jelly candy, soups, sauces, and more. It is a popular vegetarian alternative to gelatin. Vegetarians and vegans do not use gelatin because it is made from animal bones, skin, and connective tissue.
Characteristics of Agar
Agar is a prized ingredient for more reasons than just being vegetarian. Unlike gelatin, which melts at around body temperature, agar will stay solid at warmer temperatures. In fact, agar solidifies at temperatures below 122 F/50 C, which means that refrigeration is not required to set an agar gel.
Agar is also a much more powerful gelling agent than gelatin. One teaspoon of agar will give as much thickening power as 8 teaspoons of gelatin. It is important to note that although both agar and gelatin will solidify liquids, the resulting textures are slightly different.
Agar will not impart any color, flavor, or odor to the food to which it is added.
Nutritional Value of Agar
Agar is 80 percent fiber, contains no fat, no protein, and only a small amount of carbohydrates. Ten grams (2 tablespoons) of agar contains only 3 calories, derived from its small amount of carbohydrates. Due to agar's high levels of fiber, agar is sometimes used as a dietary aid to promote fullness or as a laxative. Agar also contains a small amount of iodine and other trace minerals.
How to Use Agar
Because of agar's high melting point, it must be dissolved in hot water before using. Typically, agar is added to a liquid and brought to a boil to ensure it is completely dissolved. Other ingredients can be added at that time, but the temperature of the mixture must remain above 122 F/50 C, or the mixture will instantly solidify.
Once all of the ingredients are added, the mixture can be poured into a mold and allowed to cool and solidify. No refrigeration is needed to solidify the mixture, but you may want to refrigerate for food safety reasons, depending on the ingredients used.
The amount of agar needed will depend on the variety used. Agar flakes are not as dense as agar powder, and more will be needed to gel the same amount of fluid. One teaspoon of agar powder will thicken approximately 1 cup of liquid, whereas 1 tablespoon of agar flakes will be needed to thicken 1 cup of liquid. Always refer to the package directions to get the exact ratio needed.
Where to Purchase Agar
Because agar is a popular vegetarian alternative to gelatin, it is commonly sold at health food stores. Larger grocery stores that have an adequate natural or health foods selection may also carry agar. Agar is also a common ingredient in many Asian desserts, so it can easily be found in Asian and other ethnic markets. You can also buy agar from online vendors if that is more convenient.