Iota carrageenan is most commonly used to set dairy-based puddings, as it reacts so strongly with the protein casein, found in milk and cream. The natural powder is extracted from a red seaweed, though the carrageenan powder itself is odourless, without a strong taste.
Iota carrageenan creates a beautifully smooth, melt-in-the-mouth feel, and more elastic than kappa carrageenan. Iota carrageenan dissolves in liquids to be both colourless and odourless, which means that it doesn¡řt affect natural colours or taste. Gels or jellies created with iota carrageenan are also thermo-reversible, meaning that they can be frozen, reheated, re-cooled and re-moulded.¡Å
Iota carrageenan is at its best when used for a thick-set custard, with the ratio of 0.15g iota carrageenan per 100g milk or cream. Using this ratio, the custard holds its shape in a glass or a ramekin, though it won¡řt stand alone. Using¡Å1.5g iota carrageenan with 100g cream¡Åthe pudding can be turned out and holds its shape ¡šÅthough it loses its soft mouth feel.