Arrowroot
Arrowroot is a fine, flavorless starch extracted from the rhizome of a tropical plant (Maranta arundinacea), valued in the kitchen purely as a thickener rather than for any flavor of its own. It's a popular gluten-free substitute for cornstarch, thickening liquids to a glossier, clearer finish.
Where It Comes From
Arrowroot needs a warm, humid, frost-free climate and a long growing season to bulk up its starchy rhizome, making it impractical for most home gardens outside the tropics. Nearly everyone encounters arrowroot only as a purchased powder rather than a home-grown crop.
Culinary Uses
Arrowroot thickens sauces, pie fillings, and glazes to a clear, glossy finish without the cloudiness cornstarch can leave behind, and it holds up better than cornstarch in acidic mixtures like fruit fillings. Unlike flour-based thickeners, it doesn't need long cooking to lose a raw taste, so it's often stirred in near the end of cooking.
Mix arrowroot with cold liquid before adding it to a hot dish — adding the dry powder directly to heat causes it to clump instead of thickening smoothly.