Cornstarch and tapioca flour are both silky powders known as starch thickeners. These and other starch thickeners are favored in baking because they don't noticeably alter the finished product's flavor and they don't add much fat, unlike protein thickeners. Tapioca flour is preferred for items baked at a low temperature and that benefit from the glossy sheen it imparts. While cornstarch can serve as a substitute for tapioca flour in many baked goods, it won't ever work perfectly.
1 Divide the required quantity of tapioca flour in your recipe by two; you only need half as much cornstarch. For example, a recipe calling for 2 tablespoons of tapioca flour requires only 1 tablespoon of cornstarch.
2 Measure out the resulting quantity of cornstarch with a measuring spoon or cup. Level the spoon or measuring cup with a knife for precision. Remember that baking, unlike cooking, requires exact measurements for the necessary chemical interactions to work properly.
3 Mix the cornstarch with an equal amount of cold water until it forms a loose paste-like consistency. Stir gently with a spoon. Add this slurry to the batter or sauce you're thickening.
Items you will need
- Measuring spoons or cups
- One tablespoon of cornstarch thickens 1 cup of liquid.
- When baking, measure dry ingredients in measuring spoons or cups made for dry ingredients and measure wet ingredients in measuring cups made for liquids.
- It's not a great idea to substitute cornstarch for tapioca flour if your baked goods will be frozen or if they contain an acidic liquid, such as orange or lemon juice. Cornstarch separates in sauces and becomes spongy when frozen, and breaks down when mixed with an acidic liquid. Arrowroot often makes a better substitute in these instances.
- Substituting cornstarch for tapioca flour will fail to provide the same shiny look to your baked products, so something like a pie filling will look duller.
- Conditions that commonly cause cornstarch to not thicken properly include using more sweetener than liquid, a high proportion of fat in the recipe, using an acidic liquid, excessive or rough stirring of the batter or sauce, and cooking for an excessively long or very short period of time.
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