Arrowroot
A root starch that sets clearer and softer than cornflour and tolerates acid better — and breaks down if held at heat.
Also called arrowroot powder (US); arrowroot starch (INTERNATIONAL); arrowroot flour (US)
Arrowroot is starch extracted from the rhizome of several tropical plants. It behaves like the other pure starches in outline and differs in three ways that decide when it is chosen.
It gelatinises at a lower temperature than cornflour and sets to a notably clearer, glossier gel — which is why it is preferred for fruit glazes and anything meant to look transparent.
It tolerates acid better than cornflour, whose thickening weakens in an acidic mixture. That makes it the sensible starch for a sharp fruit filling.
And it breaks down with prolonged heat or vigorous stirring, thinning back out after it has thickened. That is the reverse of cornflour’s behaviour and it is the reason arrowroot is added late and cooked briefly.
In gluten-free blends it appears alongside tapioca and potato starch as one of the light starches that give lift and a tender crumb, and in that role the differences between them are much smaller than they are in a sauce.
What changes if it is left out
Cornflour thickens comparably at a slightly higher temperature, sets cloudier and firmer, and handles a long cook better while handling acid worse. Tapioca sits between them and sets stringier.
Directional comparisons that are consistent across the professional literature consulted. No controlled measurement of the differences was read, and no temperatures are asserted.
RecordedEstablished practice, not a measured result
Related
What it does
Structure building
A root starch that gelatinises clearer and at a lower temperature than cornflour, and breaks down if held at heat.
Compared in
Cornflour vs tapioca vs potato starch vs arrowroot
A subject of the comparison, so it is reachable from the record a reader is more likely to land on first.