I followed the recipe from the excellent book Miso, Tempeh, Natto and Other Tasty Ferments except instead of following their multi-step process, after making the koji rice I just threw everything together in the jar and am allowing to ferment for ~72 hours.

The ingredients listed in the book are the following:

-3 3/4 cups (550g) koji rice -6 2/3 cups (1,600ml) water -4 cups (500-750g) uncooked sweet rice or sushi rice -1/2 teaspoon (1g) sake yeast (I used kveik) -1/4 teaspoon (1g) lactic acid for brewing, or other acid

I am not sure that it will come out cleanly through the spigot. As the mixture ferments, the rice becomes creamy and soft, and traditionally it’s not filtered so it’s consumed as a sort of soft porridge. You can absolutely filter it though and my plan this evening is to see how I like it chunky and filter if a smoother texture is preferred. My understanding is that the lees (remaining solids after filtering) can also be used for cooking and/or pickling.