A gave me a koji / miso making kit. Exciting, but several days' work followed by a wait of at least a month to see if even the quickest kind of miso is good...
I wasn't sure when I would get around to it, but travel plans this weekend fell through, and S is away, so I thought: why not do it now? And, you know, I just realised, incubating the koji felt a little like looking after a pet or a baby. So, it kept me company!
The starter (and instructions) came from
this awesome website.
6 cups of polished rice
2 tsp koji starter
Day 1 (evening):
Rinse the rice until the water runs clear. Put in a large container, cover to double its depth with fresh, cold water and leave to soak for 6-12 hours.
Day 2:
Put ~1 1/2 inches of fresh water in the bottom of a large pan for steaming. Put steamer in it and line the steamer with a ~1 foot square of muslin or cheesecloth. Put the rice inside the muslin. Cover the pan and bring to a boil. Steam the rice for 50 min starting from when the steam rises through the rice as well as round the edges.
Meanwhile, toast 1/4 cup of flour in a frying pan to sanitise, then tip into a bowl and let cool. Add 2 tsp of koji starter to the flour and mix well.
Lay out two layers of towel in a 2 foot square, with another two layers
of towel in the middle and a 2 foot layer of sheeting in the middle. When 50 min is up, lift the rice out of the steamer carefully along with the muslin. Carefully transfer the rice from the muslin to the middle of the sheet. Spread out to into a square about a foot long, about 1 inch thick, mixing the rice with your fingers (I wore fresh lab gloves anytime I handled the rice) to break down any lumps and spread out any pockets of wetness or stickiness.
Let the rice cool to ~ 40C, then wrap it up, first in the sheet, then in the towel layers. Transfer the bundle to a 30C incubator (I used my oven, which is gas and always a bit warm due to pilot light). Ideally you would wrap a thermometer in the middle of the rice so you can monitor the internal temperature - I only have a outdoor-style thermometer, so I monitored the temperature in the oven (typically ~32C) but not inside the bundle - tried to keep track just by comparing with body temperature using my fingers.
Every couple of hours, unwrap the rice, mix it and check the temperature. Continue for 24 hours - check it before and after going to sleep.
Day 3:
Check the rice when you wake up. Prepare a large (8x12x3 in) pyrex dish by washing in hot soapy water, pouring boiling water oven, then inverting and leaving to air dry.
When the rice has been incubating for 24 hours open it up and check on it. The rice should look as it is covered with white floury stuff. Mix well, breaking up any lumps, and transfer to the prepared dish. Spread out evenly, then create furrows 1 inch deep and 2 inches apart (to help it not to overheat in the middle). Cover with a 'lid' made of clingfilm, touching the surface of the rice to keep in the moisture. Wrap back up in the towels and put back in the 30C incubator. Check it every 4 hours, stirring and recreating the furrows each time. Modify the amount of insulation (and temperature if you can) if it is overheating. Check just before and after going to sleep.
Day 4:
Check in the morning and keep incubating until ~ 48h. It should look nice and white and powdery, grains should break easily and show the powderiness extending about halfway through. When it's ready take it out of the incubator and let cool to room temperature, stirring occasionally. Now it is ready for
miso making!
Notes: I used the rice Anna left (cheap long grain). It was not cooked when I stopped steaming it - not sure if it should have been? I got a bit confused about steaming time, so... On Day 4 (48h) the powderiness did not seem to have extended all the way through the grains - perhaps due to undercooking rice? But it did smell good and look reasonably powdery so I decided to try some anyway. I set
some miso up that day (used 3 1/2 cups), left the remaining koji @ 30C for another ~12 hours before setting up more miso (used another 3 1/2 cups), and after that stored the remaining koji (2 3/4 cups) in the freezer). So, total koji yield was nearly 10 cups - enough for approx. three batches of light miso.