Rice flour for Wagashi
Mochi-ko is a glutinous rice flour, it is made from mochigome(glutinous, short grain rice). Glutinous rice is washed, dried and then ground very fine. Mochiko is used for making mochigashi(all kinds of mochi-based sweets). It is more complicated to use at home then the other glutinous rice flour called shiratama-ko, this is more elastic. In Germany you can get Japanese mochiko flour at Dae Yang(online), in USA there is a brand from Koda Farms.
もち とりこ Mochitori-ko is a mixture of starch and mochiko (not a special mochi flour), it is mostly used to prevent mochi cakes to stick to everything.
Shiratama-ko is the other widely used glutinous rice flour. Like mochiko, it's made from mochigome rice; however through the special processing its properties are significantly changed: mochi rice is washed, soaked in water and ground very finely in water (in a kind of special mill).The milk white liquid is then pressed, dried and crushed. The flour isn’t a fine powder but coarse granules.
Shiratama-ko was formerly known as 寒晒粉 kan-sarashi-ko. Soaking was always done in very cold water in winter, and without refrigerators this flour could be produced only in the cold season.
Difference between shiratamako and mochiko?
There is a huge difference in taste and texture between both rice flours.
Mochi made with shiratamako are more elastic but also “rubbery”. However shiratamako is much easier to use, especially for beginners, if you like to make mochi at home. But not everyone likes the consistency, so often both flours are mixed; sometimes it is helpful to add also small part joushinko flour.
Mochiko flour is less elastic but has a nice "mouth feeling", it dissolves faster, but, the taste of shiratamako is better, finer(more "creamy").
Both flours are available in different levels depending on rice quality, for example, habutae mochiko is the "highest class", named after habutae=silk.
I've tried few different grades of shiratamako, and it is true, you will notice a difference in taste, the quality of the used mochigome plays a major role.
The ordinary glutinous rice flours(pic) available in many shops with asian ingredients are unfortunately not really suitable. They are mostly from Thailand or China and are made from a other rice variety(long grain). The taste is rather different, and there is a difference in water absorption. I have tried to make dango or mochi with this kind of rice flour but unfortunately, it didn't work at all, or the end result was not very good in taste and texture. It was always a big failure and disappointment. The difference between wagashi made with original japanese flours was enormous. Picture:glutinous/white rice flour.