What Is Agar Agar?

Agar-agar, sometimes referred to simply as agar, is also called Kanten, Japenese gelatine, or China grass. It is a gum derived from red seaweeds of the genera Gelidium Gracilaria and Eucheuma or from others of related species of the class Rhodophyceae. It contains the polysaccharides agarose and agaropectin and is usually used to form gels for cooking, to make dental impressions, or as a culture for bacteria, which is its main use in the West, where it is not used for cooking as often as in the East. ^{1 2}

Agar is produced in Portugal, Spain, Morocco, and Japan. The seaweeds used to derive it are gathered in similar ways as the seaweeds for carrageenan production but it is more expensive than all the other seaweed products and much effort has been made to substitute carrageenan. ³

Unlike gelatin, agar both melts and sets at a higher temperature. It needs 95°C (203°F) to melt and so it will not dissolve in a bowl of soup and is insoluble in cold water. To gel, it only requires 32 to 40°C (90 to 104°F), making refrigeration completely unnecessary, although the cold will speed up the cooling and thus the gelling of the mold.

Grayish white in color, Agar-Agar is used extensively in Japanese, Chinese, and Southeast Asian cooking. In Japan it may be called Kanten and it was originally extracted from a Japenese red alga called tengusa. It is used to make gelatinous, slippery sweets which are flavored with almond, coconut, or black soybeans as well as small molded jellies flavored with jasmine, pandan, or, in Southeast Asia, creamed corn. In those countries, it is sold in most food markets where it comes as either long strands or feathery rectangular sticks. The long strands are sometimes used as noodles in cold Chinese salads with chicken, meat, and vegetables. It is the “bird’s nest” in the famous Chinese soup called Bird’s Nest Soup. Otherwise, it is boiled until it dissolves (possibly with sugar) and then molded along with other ingredients. It may be sold also in powder form, and can be used as a general thickening agent for soups or sauces. ^{4 5 6}

Agar is used to make a very popular but unusual cold drink in Mauritius, the small island nation off the southeast coast of Africa. There, chopped agar-agar strips are added to a cold sweet milk drink called Alooda Glacée, which is flavored with basil, vanilla and/or almond.

Use in Manufactured Foods

Agar’s advantages in foods comes from the heat tolerance of the gels, stability in acids, and a lack of reactivity of other food ingredients. It makes a firm gel at very low concentrations and is used typically between 0.5 and 2.0%. The high melting temperature means that once the gel is formed, it remains stable up to 80°C. It can gel in a wide range of pH conditions, except in very high temperatures, where it may be hydrolized by acid. It has no metallic taste, as may be found with alginates or carrageenan. Also, since it does not inhibit the growth of bacteria, is is useful in fermented like yogurt. Some general uses are:

• water dessert jellies
• vegetable, meat, and fish aspics
• artificial caviar
• candies, fruit jellies, nougat, candy fillings, piping gels, jellies, jams
• icings and glazes for pastries, cakes, and doughnuts
• dairy products like flans, puddings, custards, creams, flavored milks, and ice cream
• fermented products like yogurt and sour cream
• canned meat and fish products
• soups and sauces
• clarifying agent for wine, juice, and vinegar
• fiber component in health foods

Agar is used differently for manufactured foods in different parts of the world, where it is closely linked to tradition. Even though it was introduced to Europe and the United States over a century ago, it has only had limited use in food products, although professional chefs are growing more familiar with it. In the Americas, Europe, and Asia, it finds moderate use in ice cream, sherbert, custard puddings, cookies, candies, jams, jellies, and fruit desserts, where it is used more extensively in Asia. In the USA and Europe, it is sometimes used in processed cheese. The powdered form has come to largely replace the traditional strips or sheets.

It is used extensively to make packaged versions of a traditional dessert from Argentina, Paraguay and Uruguay called Dulce de batata, a sticky sweet potato paste or “jam”, sometimes called the poorman’s or “Policeman’s” desert (el postre del pobre or el postre del vigilante).

Substitute for Agar In Recipes

Generally, granular gelatin can be substituted for agar agar in recipes. Use 1 3/4 teaspoons of gelatin for every teaspoon of agar. Agar however, behaves differently from gelatin. It sets at room temperature, and to a much firmer consistency. Also, it will not melt in your mouth like gelatin, but will crumble down into smaller and smaller pieces. Products made with gelatin instead of agar will not be exactly the same. Vegan cooks should keep in mind that agar is vegetarian, being derived from seaweed, while gelatin is often animal-derived.

Safety Legislation

The FDA classified Agar as GRAS (Generally Recognized as Safe) in 1972. It was permitted in food with specified maximum levels:

In Europe, it is permitted for use in food quantum satis, meaning whatever level is required for the desired effect in a product. ^{7 8}

Want to know more about Asian ingredients? Check out Asian Ingredients: A Guide to the Foodstuffs of China, Japan, Korea, Thailand and Vietnam by Bruce Cost.

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1. Cost, Bruce. Asian Ingredients: A Guide to the Foodstuffs of China, Japan, Korea, Thailand, and Vietnam. New York: HarperPerennial, 2000.
2. Igoe, Robert S., and Y. H. Hui. Dictionary of Food Ingredients. Gaithersburg, MD: Aspen, 2001.
3. Somogyi, Laszlo P., Yiu Hin. Hui, and Diane M. Barrett. Processing Fruits: Science and Technology. Lancaster: Technomic Publ., 1996
4. Cost, Bruce. Asian Ingredients: A Guide to the Foodstuffs of China, Japan, Korea, Thailand, and Vietnam. New York: HarperPerennial, 2000.
5.  Igoe, Robert S., and Y. H. Hui. Dictionary of Food Ingredients. Gaithersburg, MD: Aspen, 2001.
6. Imeson, A. Food Stabilisers, Thickeners and Gelling Agents. Chichester, U.K.: Wiley-Blackwell Pub., 2010.
7. Imeson, A. Food Stabilisers, Thickeners and Gelling Agents. Chichester, U.K.: Wiley-Blackwell Pub., 2010.
8. Food and Drug Administration. Code of Federal Regulations, Title 21, Food and Drugs, Pt. 170-199, Revised as of April 1, 2011