Rorie’s Arrowroot starch. Arrowroot is an easier to digest, lower glycemic neutral tasting starch that can be used cup for cup in some recipes that call for potato starch. In many recipes you will need to use less arrowroot starch as arrowroot has a higher hydration than potato starch.
Use this approximate guide that @naomi_tgis came up with when testing out your favorite recipes using arrowroot starch in place of potato starch.
2 tsp arrowroot = 1 tbsp potato starch
1/3 arrowroot = 1/2 c potato starch
1/2 c arrowroot =3/4 c potato starch
2/3 c arrowroot = 1 c potato starch

Our top tips after tons of arrowroot starch recipe testing!
* In most cases arrowroot starch works best in baking when combined with other flours.
* Arrowroot starch works best with recipes that have a lower fat content. Recipes that call for a lot of oil will not be as good.
* You can substitute two teaspoons of arrowroot for one tablespoon ( 3 tsp) of cornstarch.
*Use arrowroot starch to thicken stews, gravies, sauces, pie fillings, puddings and custards.
*Coat chicken or fish in arrowroot starch before dipping into egg, followed by my coating crumbs for frying or baking.
*Arrowroot starch works great with everything but dairy.
* As an egg replacer, mix together 1 tablespoon arrowroot, 1 tablespoon oil, and ¼ cup water for each egg.