This hydrocolloid, first produced from red seaweed in Ireland, eventually made its way beyond Europe to North America and the Far East.

Commercially, it comes in three varieties based on the degree of sulfation: Kappa, Lambda, and Iota. Fancy names, right? Kappa carrageenan is sensitive to potassium—it just can’t hide its feelings. Iota, on the other hand, reacts to both potassium and calcium. For both types, the gelling power hits its peak in the presence of these elements.

All carrageenans dissolve in hot water, but only Lambda can dissolve in cold water. Kappa carrageenan forms the strongest gel, while Iota creates a flexible gel with excellent water-holding capacity. Lambda, lacking gelling properties, is perfect for products that need viscosity, like beverages. 

When fully refined during production, carrageenan is clear and neutral in color. If semi-refined, you get a more cost-effective product with a higher gel strength compared to fully refined versions, though it might not be as transparent and glossy. The choice is yours.

Carrageenan varieties work across a broad pH range but can easily degrade at high temperatures. They are thermo-reversible but not stress-reversible.