Cornstarch is the most common thickener in modern cooking. Here's what to use instead — with exact ratios for each application.
Cornstarch (called cornflour in the UK and Commonwealth countries) is a fine white powder made from the starchy endosperm of corn kernels. It is a pure starch — no protein, no fibre — which gives it a very clean thickening ability. When mixed with cold liquid and heated, the starch granules absorb water, swell, and form a thick, semi-transparent gel.
Cornstarch is used as a thickener (sauces, gravies, pie fillings, puddings), as a coating in deep frying (for extra crispiness), and in small quantities in baking (cake flour can be approximated by replacing some AP flour with cornstarch to lower protein content).
Made from the arrowroot plant. Thickens at a lower temperature than cornstarch, produces a clearer gel, and freezes and thaws without breaking down (cornstarch-thickened sauces can turn watery when frozen). The most versatile cornstarch substitute. Does not hold well at prolonged high heat.
Made from the cassava root. Produces a very clear, slightly glossy gel — ideal for pie fillings and fruit sauces where visual clarity matters. Slightly chewier texture than cornstarch in some applications. Does not break down when frozen.
AP flour thickens through both starch gelatinisation and protein absorption. Less efficient than cornstarch — use double the quantity. Produces an opaque sauce (cornstarch sauces can be semi-transparent). Needs to be cooked for at least 2 minutes to eliminate raw flour taste.
Very fine starch with a neutral flavour. Thickens at lower temperatures than cornstarch. Can become slightly gluey if overcooked. Works well in sauces and soups.
Ground flaxseed absorbs water and creates a thick, slightly gel-like consistency. Adds omega-3 fatty acids and fibre. Has a mild nutty flavour and adds texture — not suitable for clear sauces. Works well in smoothies, oatmeal, and as a thickener in hearty soups.