This recipe and photographs have been provided courtesy of Nancy Singleton Hachisu, author of Preserving the Japanese Way. Use your miso in Nancy's recipe for miso squid.
Homemade brown rice miso | TEZUKURI GENMAI MISO
MAKES 6 POUNDS (3.5 KG)
Although tackling making miso may seem intimidating, it is really much simpler than you may imagine. I encourage you to take the plunge because when you end up with a vat of homemade miso that has your own taste, the sense of accomplishment is unrivaled.
Mitoku organic brown rice koji and barley koji can be ordered through the Natural Import Company, an excellent source for top-quality Japanese ingredients, and white rice koji is available online at South River in Massachusetts or Cold Mountain Miso. This method follows the one used at the Yamaki Jozo miso-making workshop. The large percentage of koji results in a full-flavored, almost sweet miso. Good-quality dried soybeans are readily found in the bulk organic section of your best organic shop. Though I use Japanese sea salt, just use a good-quality local or even Italian white sea salt, preferably naturally dried. Make miso in the cool months from late November through early March to give it time to rest before the fermentation arc starts to climb as the weather warms in the spring and summer.
2 pounds (1 kg) best-quality non-GMO dried soybeans
2 teaspoons best-quality organic miso (or previous year’s homemade) to use as seed miso for the new batch
2 pounds (1 kg) brown rice koji
14 ounces (400 g) fine white sea salt
Soak the soybeans for 18 hours in a large pot of cold filtered water. Drain the beans, return them to the pot, and refill the pot to about 5 inches (10 cm) above the beans. Bring to a boil over high heat, lower to a simmer, and cook for about 1 1/2to 2 hours, uncovered, until the beans are soft. The idea here is to simmer the beans in just enough liquid so they cook well but eventually most of the liquid is boiled away by the time the beans are cooked. Traditionally, the beans are steamed for 1 1/2 hours in wooden steaming boxes stacked over a large cauldron set over a very hot wood fire. The beans can also be cooked in batches in a pressure cooker for about 20 minutes over high heat. (N.B.: If you steam the beans you will need to double the amount of seed miso and water that you add to the mash with the koji and salt.) While the beans are cooking, slowly whisk 1/2 cup (125 cc) of hot water into the 2 teaspoons seed miso and cool to room temperature (the solution should be like a very thin miso soup in consistency).
Drain the cooked beans and start mashing them to a coarse consistency. I like to grind them roughly in batches in the Japanese grinding bowl (suribachi). Alternatively, you could run the cooked soybeans through a sterilized meat grinder. Or you can opt for the low-tech squeeze between your thumb and index finger method. When the beans are smashed to your satisfaction (chunky or smooth), they will also be cooled enough to measure in the koji—they should be just off warm at the most (too hot and it kills the spores). Sprinkle in about 80% of the salt along with the seed miso (miso thinned with water). Knead well to distribute the koji and salt with the mashed beans.
Form tennis ball—sized spheres of bean mash and throw them into a large crockery pot, small wooden barrel, or food-grade plastic vat with all of your might. Whack! Splot! The container should be set on the floor, and it probably makes sense to have a piece of plastic sheeting underneath the container to catch any misthrows. You are looking for a satisfying splat that sounds like thunk rather than a weak glurp. Or (if you are lazy like me, with stunningly bad aim), you might mash the balls in with your fist and the heel of your hand to ensure that all air pockets have been filled. The bean mash should only fill the container about half full. Pat down the surface of the mash with the flat of your palm and sprinkle with the remaining 20% portion of salt.
Smooth a clean muslin cloth across the surface of the mash and let it drape down over the sides of the container to keep out flying leaves or other debris. Place a wooden or plastic drop lid on top of the cloth-covered mash surface and weight evenly with rocks or heavy objects that equal at least the weight of the mash. Cover with one more large muslin cloth and wind some twine a couple of times around the circumference of the barrel to tie the cloth in place. The cloth will act as a mold barrier and will become scarily dusted with green mold spores, so don’t skip or replace with plastic. Carefully remove to wash when you stir the miso.
Let the young miso sit undisturbed in a shaded area outside until the weather warms. From May, start stirring the miso about once a month to avoid mold as the fermentation arc starts to ramp up. During the hottest period, you should probably stir the miso (from the bottom up) every 2 weeks to avoid mold forming. Ideally the weather should become muggy, and the temperatures should rise to about 100°F (38°C) at the height of the summer. But avoid direct sunlight. If you see any mold on the surface, carefully scrape it off. Clean the inside surface walls of the container with a vodka- or shochu-soaked cloth to deter mold. If you are feeling particularly adventurous, you could smooth a 1-inch (2.5-cm) layer of sake lees across the surface of the miso in June or July to seal and inhibit mold produced by oxidization. In this case, you really want to completely cover the surface to make a homogeneous layer (you still need to use the cloth, drop lid, weights, and outside cloth cover). Peel off the sake lees when the weather turns cool in the late fall, and recycle the lees as an instant pickling bed.
If you have not sealed the miso with sake lees, check the miso after the summer to see if it has mellowed to your liking. At this point, you can refrigerate it or just leave the miso in its fermenting container until you start your next batch in the coming winter. No need for weights once the miso is done—you can leave it outside if the weather is cool; otherwise store it in the fridge.
VARIATIONS: I have heard of people using different beans such as chickpeas or azuki; I would not. In Japan miso is always made from soybeans. Also it is fine to use white rice koji instead of the brown rice koji.