View All Molecular Gastronomy Glossary

Sodium Alginate

What is Sodium Alginate?

Sodium alginate, which is also called Algin is a natural gelling agent taken from the cell walls of certain brown seaweed species. This salt is obtained by drying the seaweed, followed by cleaning, boiling, gelling and pulverizing it. A light yellow powder is produced from the process.

When dissolved in liquids, sodium alginate acts as a thickener, creating a viscous fluid. Conversely, when this is used with calcium it forms a gel through a cold process.

In molecular gastronomy, sodium alginate is most commonly used as a texturizing agent. Foams and sauces may be created with use of this. It is also used in spherification for the creation of pearls, raviolis, mock caviar, marbles and spheres.

A concentration of 0.5g to 1g for every 100g is often used. Sodium alginate can be used both directly by dissolving it into the liquid that needs to be gelled, such as in the case of basic spherification.

It may also be used inversely, by adding it directly to a bath, as in the case of reverse spherification. Since it is versatile, sodium alginate is soluble in both hot and cold liquids, and gels made with it will set at any temperature.