Here's the recipe I got while in Korea earlier this year:
DONG DONG JU Recipe
Korean rice: 1KG
Yeast – 8 gm., any wine yeast will do for DDJ in Korea.
Nooruk - enzyme 200gm. - made with crushed wheat malt.
Clean water - 1.6 liter, I used filtered water
Method: (all equipment must be sanitized, hands included)
1) Wash 1KG of Korean rice and soak overnight.
2) Allow to drain for at least 2 hours prior to steaming.
3) Into the steamer for 1 hour of steam cooking.
4) After rice is well cooked, spread it onto a tray to cool to room temperature.
5) After it is cooled, add crushed Nooruk and yeast. (wear a disposable plastic glove, sprayed with Iodophor to mix thoroughly by hand).
6) Once thoroughly mixed, the rice is ready to be placed into a fermenter.
7) Add 1.6L of clean or bottled water into the mixture.
Basically what happens is the nooruk (amylase enzyme) converts the steamed rice into sugar for fermentation. Nooruk is made with crushed wheat malt and water. It is a mold that occurs naturally with wheat malt.
Almost 2 hours after the mash is in the fermenter, all water is absorbed by the rice malt
After 3 days stir the mash twice a day until it is ready to serve in 10 days.
I haven't made this yet because I don't have a steamer, but I have all the other ingredients.
Dong means sh*t in Korean. Dongdongju is basically an unfiltered mokeli (no shi*t floating in it).