For the raw paste, mix approximately:
1 part mochiko (sweet rice flour) 1 part komon nuka (de-fatted rice bran) 1 part water (cool tap)
Amounts depend upon how much you need for your project. 1 cup of each is a good place to start, and will be plenty to paste at least 1 yard of fabric with approx. 50% paste coverage.
Mixing the raw paste
Sift or strain the two rice flours together so there are no lumps. Add cold water a little bit at a time, mixing after each addition with your hands. The purpose of this thorough mixing is to ensure a smooth, lump-free paste.
Keep adding a little water at a time and mixing thoroughly until the raw paste feels somewhat like wood putty, pie crust, your ear lobe, or soft clay. It will hold together easily when you squeeze it in your hands, but it won’t be sticky or dripping wet. Break it up into loose chunks and cover it with a damp cloth. Let it sit for about 30-60 minutes before steaming. Better yet, let it sit overnight in a cool place, but refrigeration is not necessary (except perhaps in summer).
To steam, use a set up like a double boiler or layered Asian style steamer. Line the top steamer basket with a damp cloth.
Form golf-ball size round chunks (no need to be fussy here) of the raw paste and put them in the steamer basket, on the damp cloth. Cover over them with the edges of the damp cloth, then put the cover on the steamer. Once the water boils, turn down to low, and steam for about one hour.
When is it done?
It’s done when the color (all the way to the center of each ball) turns from a light brown almost like a manila folder to a darker brown, somewhat like peanut butter. Insert a stainless steel knife to check this.
While the paste is steaming, prepare your ingredients for the final mashing/mixing step. You’ll want some cool tap water and also some salt water in separate containers. Add a bit of salt to one cup (i.e. 1 tsp. for average batch of paste); stir to dissolve. Amounts depend upon how much paste you are making, but if you prepare 1 cup of each you’ll have plenty.
Get out your bowl and pestle, scraper, and the optional ingredients (see below) if you are using them.
Mashing the paste after steaming:
Quickly dump the cooked paste into a warm bowl. Immediately begin beating thoroughly with a wooden pestle, wooden broom handle, or large wooden spoon. The paste will be very sticky.
Begin adding plain water and/or salt water little by little, beating after each addition. The salt water will help the paste hold on to moisture from the air, more crucial during the cold, dry winter here in the upper Midwest than in the humid summers. You can leave it out during humid summer days.
The consistency of the paste should be such that, when you mound it in the center of the bowl, it will gradually return to a flat surface (or almost flat) after about 10-15 seconds. It will also plop of your spatula or spoon on it’s own. But it should not be too drippy. Experience is the best teacher here.
It's best to allow it to reach room temperature before using it. Sometimes you'll need to mix in a bit more water before using it because it thickens as it cools.
Finally, the paste can be kept in the refrigerator 2-3 days while you are using it. Put a little tap water on the top surface to keep it from drying out (pour this off before use), cover, and refrigerate. You may also use plastic wrap, just try not to trap air bubbles on top of the paste. Do not freeze. If you've wondered whether you've kept it too long, in my experience it gets slimy before it gets moldy. You will know when it's time to toss it out!
Additional optional ingredients to add while doing the final mixing:
CALX: (calcium hydroxide – a.k.a. lime, chalk, etc.) – for extra elasticity; add a little to water (i.e. 1 tsp); let it settle to the bottom, and then decant some of this water into your paste while mixing. It will turn the paste slightly yellowish.
GLYCERIN helps keep the paste the right consistency when dry on the cloth (it is an immolient), so it isn’t as susceptible to changes in humidity and weather. Just add a few drops to your paste while mashing.
For more information on making rice paste resist, see John's Marshall's detailed instructions.