Sodium alginate, also called algin, is a salt of the natural polysaccharide alginic acid 1 that is found in brown algae (seaweed) in the class Phaeophyceae. Alginic acid was discovered in 1881 by ...

Cut and mixed with water to make a thick gel. Diluted with more water and filtered. Mixture evaporated and further processed to make sodium alginate powder.