Pastry thickeners: choosing starch, agar agar or pectin

Creams, sliceable inserts, jams and mousses need different structures. In pastry-making, choose a thickener according to the method and mouthfeel, rather than simply looking for a powder that makes something thicker.

Distinguish the functions

Starches increase the consistency of the water phase. Traditional starches require cooking; a product such as Ultratex can also work without heat. Agar agar, by contrast, forms a more clearly defined gel after dissolving and cooling.

Pectin is a family of ingredients: a pectin for high-sugar jam does not automatically work like a low-methoxyl pectin or an NH formulation. Identify the type before specifying a dose.

Design the process

• For a cooked cream, consider the temperature and time needed by the starch.
• For a fruit insert, check sugar, acidity and setting.
• For a mousse, plan air incorporation, structure and temperature sequence separately.
• For freezing and thawing, test the complete preparation on a small scale.

Do not heat any mixture indiscriminately and assume it can then be whipped. A cream already combined with other ingredients and heated needs a method formulated for that process.

Assess more than the cut

Taste after resting and at serving temperature. A cream that looks ideal when freshly made may become too firm; a jelly that holds well in a mould may be unpleasant in a large portion.

Read the comparison of pectin, agar and carrageenan and the mango and coconut terrine recipe, where the textures of both layers need to be considered together.