Very much so. Viscosity, stability, texture, and translucency are all affected because the molecular structure differs with each type of starch, be it derived from wheat, corn, rice, rye, oats, millet, barley, or other cereal grain; from cassava, potato, or other root or tuber; from soybeans, peanuts, or other legumes; or from almonds or other nuts.

For example, if you substitute cornstarch for white wheat flour, you will have to alter the formulas given earlier. Use half the quantity of cornstarch because it has twice the thickening power of white wheat flour. If you substitute arrowroot, use slightly less than half the quantity because arrowroot has slightly more than double the thickening power of white wheat flour.

Whole wheat flour is less practical as a thickener than white wheat flour because the refined product has a higher starch content. Our experiments indicate that cake or pastry white wheat flour is more suitable than its all-purpose counterpart, which in turn is better than baker's flour. The last type produces a grainy sauce reminiscent of the pastes we used in elementary school. Specially processed instant wheat flours, such as the Wondra brand, can be sprinkled directly into sauces but direly lack stability.

Regular white wheat flour is superior to cornstarch and arrowroot in stability; a sauce made with it is less likely to separate and break down when subjected to prolonged heat. Both cornstarch and arrowroot produce a sauce that is smoother and more transparent, desirable qualities for many sophisticated dishes. Those two starches are generally incorporated into a sauce by means of using slurry (a fluid blend of flour and a liquid such as water) rather than the roux or beurre manie method, and this addition is usually done near the end, rather than at the beginning, of the sauce-making process.

** Asian Recipes **