The common flours used in Thai desserts: sticky rice flour, rice flour, cassave starch, wheat flour and mung bean flour.
Sticky Rice Flour: Sticky rice flour is also referred to as “sweet rice powder” or “glutinous rice flour.” It is made from short-grain sticky rice that becomes moist, firm and sticky when cooked. This is due to its proportionally higher number of waxy starch molecules. With its chewy texture, sticky rice flour is a favorite base for buns and pastries. Sticky rice flour is often combined with plain rice flour to create a variety of Thai desserts. In Thailand there are 2 types of sticky rice flour: wet and dry. Wet sticky rice flour is finely milled with water, whereas dry sticky rice flour is finely milled without water. When buying sticky rice flour, choose products that have a white color and no smell or moisture.
Rice Flour: Rice flour is used to thicken various dishes and is also an important ingredient in various Thai desserts. Rice flour is a good substitute for wheat flour, in that the latter causes digestive system irritation in those who are gluten intolerant. However, rice flour should not be used or substituted in some desserts like cakes. This is because rice flour is not finely milled like cake flour, and would not yield the same quality of desserts.Beyond the type of flour, there are many grades for each type. To buy rice flour, choose products with a white color and absence of an old smell. If you plan to make a dessert using rice flour, find flour that was finely milled so your dessert will have a smooth texture.
Wheat Flour: Wheat flour is a fine white powder that has high gluten content. There are different types of wheat flour depending on the characteristics of wheat used and the milling process. The common wheat flours are bread flour, all purpose flour and cake flour. These 3 types of wheat flour are different in the percentage of protein contained in the flour. Bread flour has the highest percentage of protein, 12%-13%, followed by all purpose flour at 9%-10% and cake four at 6%-9%. Protein content is an important key for a buyer to know because it yields different result in cooking. High protein content means more water will be absorbed and there will be a longer mixing time to achieve optimum consistency.
Mung Bean Flour: Mung bean flour is made from mung beans. It is a gluten-free flour. Some brands offer a very fine texture of flour. If the flour is not finely ground, one must grind it before use to prevent lumps. Mung bean flour comes in a variety of colors depending on how much it has been precessed. When cooking mung bean flour (with water on a stove), it turns transparent. One of the most well-known uses for mung bean flour is in so-called glass/clear noodles, very fine noodles made with a highly refined form of mung bean flour. When raw, these noodles are almost transparent, and they turn completely transparent when cooked. Khanom Salim is a Thai dessert that requires mung bean flour and cannot be substituted.
Cassave Starch: Cassave starch is often called tapioca starch (paeng sa koo). It is a refined white flour which is made from cassava root. Cassave starch is very finely textured, and is a common substitute for arrowroot starch and cornstarch. Cassave starch is gluten-free and easy to digest. It is often added to gluten-free baking as a thickener. It is broadly used as a thickener for sauces, soups and desserts in Thailand. In desserts, cassave starch is almost always used in blends with other types of flour so that desserts are more soft and sticky than when using only one type of flour.