Arrowroot powder is a type of starch that can be used instead of cornflour in many ways, including baking, but is most appreciated as a thickener of liquids because it makes sparkling clear jellies, whereas using cornflour always gives cloudy results.
Victorians credited arrowroot with many health-giving properties, noting that it was very easily digested and tolerated by children and invalids. Now we know it is not particularly nutritious, is quite high in carbohydrates and quite low in protein (gluten). It is not a wheat flour substitute in bread making but when included in biscuits it gives a specially satisfying and mild flavour.
It is made from the tuberous roots of a number of South American plants but the use of ‘arrowroot’ in connection with tapioca or tapioca root products is incorrect and misleading.
Choose the best
It should be unadulterated.
A long life if kept dry.
Arrowroot thickens more than other starches, so use two teaspoons of arrowroot instead of one tablespoon of cornflour, or one teaspoon of arrowroot for one tablespoon of flour.
If you are making a clear jelly, arrowroot powder should first be mixed into a loose slurry with cool water or other liquid before adding to a hot liquid, red or white wine or clear fruit juice, for instance; green and other aromatic teas or herb tisanes make wonderful clear jellies to serve with savoury or sweet dishes.
If used to thicken a custard or other type of cream sauce, a slurry should also be first made.
It’s important to take any arrow root mixture from the heat as soon as it has thickened, because further heating will thin it. Thus sauces intended to be served hot should be served as soon as they are ready.