Arrowroot powder is a type of starch that can be used in place of cornflour. It is often used in baking, but is best used to thicken liquids – it's ideal for making clear jellies.
Victorians credited arrowroot as having many health benefits, noting that it was very easily digested. Now, we know that while it's not particularly nutritious, it is high in carbohydrates and low in protein (or gluten). It's not a suitable wheat flour substitute for breadmaking, but it adds good flavour to biscuits.
Arrowroot is made from the tuberous roots of a number of South American plants. Any use of ‘arrowroot’ in connection with tapioca or tapioca root is incorrect and misleading.
Choose the best
Look for pure, unadulterated arrowroot.
Arrowroot has a very long shelf life if kept in a cool, dry place.
Arrowroot thickens more efficiently than other starches, so use 2 tsp arrowroot for every 1 tbsp cornflour, or 1 tsp arrowroot for 1 tbsp flour.
If you're making a clear jelly, mix arrowroot powder into a loose slurry with cool water or other liquid before adding to hot wine or fruit juice. Green or herbal teas also make wonderful clear jellies to serve with savoury or sweet dishes.
If used to thicken a custard or other cream sauce, you should also make a slurry before adding it to the hot mixture. You can do this with milk, if you like.
It’s important to remove any arrowroot-thickened mixture from the heat as soon as it's thickened to the correct consistency, because it will start to thin again if it's heated longer. Serve sauces that should be hot as soon as they're ready.