Agar - agar

Agar-agar or simply agar — texture, widely used for gelling liquids. It can be used to create cold and hot gels that do not melt at room temperature, thicken liquids and clean broths (one of the filtration methods).

Ferran Adria used agar to create spaghetti and spherify drops of liquids in chilled oil.
Agar is a natural polysaccharide (starch) found in some types of red algae. It consists of agarose and agaropectin. Unlike gelatin, whose hydrocolloidal due to proteins of animal origin, the properties of the agar obtained from bacteria. Prior to the opening of agar in modern cuisine, it was widely used in the Asian region to create desserts and jellies. Agar-Malaysian name of the ingredient derived from algae agar-agar (this explains the name). Other definitions-Japanese gelatin, Ceylon moss, kanten.

The Function Of Agar :

In small quantities, its action is similar to the action of gelatin. At higher concentrations, agar forms a strong gel that does not lose its properties at room temperature.

The Use Of Agar :

Agar is used in molecular gastronomy to create spaghetti, caviar, hot and cold gels, broth cleaning. Also agar can be used in ice cream to improve the structure.
Spaghetti using agar (also known as molecular spaghetti) - the creation of chef Ferrand Adria. They are a noodle with a width of 3-5 mm and a length of 2 m, of the liquid, Tagliavini with agar. Spaghetti can be served both cold and hot.
Cold oil spherification is a method in which a liquid containing a hydrocolloid is cooled below 32 C. Drops falling into the oil are cooled, and as they sink to the bottom take the form of a sphere.
Agar can also be used to clean broths — a method developed by Harold McGee. It is to freeze the broth containing agar, and then let it thaw in the refrigerator, on a sieve with gauze. The result is a pure consomme containing only water and taste molecules.

Properties of agar :

Temperature (gelation and melting): Heat to boiling point and keep on fire for 2 minutes. Forms a gel when cooled below 32 C. the Gel melts at a temperature above 85 C.
Texture: a Similar texture to gelatin, but is more fragile. Agar can be combined with other hydrocolloids (eg, Gellan gum) to change the texture of jelly.
Appearance: Translucent. Jelly is not as clean as when using gelatin, which should be taken into account when thinking about the appearance of the dish.
Taste: Excellent for hard gel.
Mouthfeel: may Vary depending on the content of the agar. But I think it's jelly.
Freeze/ Thaw: Not stable releases water.
Syneresis (water release): Yes, especially at low concentrations. To prevent syneresis, it is recommended to replace 0.1%-0.2% agar with carob gum.
Sharing: Allows you to create liquid gels when broken in a blender.
Hysteresis: 60 S (approximately)
Agar interaction and tolerance :

Acidity: when acidity is below 6.0, there is a weakening of properties.
Sugar content: the higher the sugar, the texture becomes firmer, but less smooth.
Alcohol: Forms gels, but as the alcohol concentration increases, the properties weaken.
The use of agar :

Concentration: 0.5 to 2% of the total liquid mass.
Dissolution in water: agar does not dissolve in cold water, the best way is to stir the agar in water, then heat and let boil for a few minutes. If you add agar already in hot water, instead of a homogeneous gel, you can get separate clots. You can also heat the agar in a small amount of liquid, and then pour into the total mass.
Principle of operation :

Agar has a double helical structure. It forms a three-dimensional framework that holds water molecules. The gelling properties of agar provide three Equatorial hydrogen atoms on 3,6-anhydro-L-galactose, forming a spiral. The interaction of spirals leads to the formation of gel.