Corn in the process of being inoculated with Aspergillus oryzae or koji (こうじー麹) It’s a pretty high maintenance process. The corn is not nixtamalized for this go around. This will be ground into masa or made into miso or a dessert. Hopefully a book will be ready by an upcoming forum.
When we make corn based horchata we typically nixtamalize the corn with which we make corn amasake, our horchata base, but not the koji. In a pinch you could use rice or oat koji. We always sour some out to a pulque type drink using some thick cooking water and yeast.
After soaking the corn, and other grains, we typically pressure steam large amounts in an 8 quart steamer. Why such a small steamer? We reuse the steaming water until the final water is almost a thickened sauce. Many of the things you can do with this corny, carbohydrate rich liquid will surprise you. There are several recipes in the book.