Koji Box

Well, finally got my koji box installed in … the basement. That was what I was trying to avoid the entire time, with the nice finish and all . It is a box after all.

On the bottom I have a 2x1 fermwrap taped down, with a turkey pan filled with pearlite and some water. It’s plugged into an internal power strip, on second thought the power strip may have been a stupid idea.

I have a 200watt ceramic heater (either on or off) connected to a temp controller. Half of the box gets to 104 in 5 minutes. I adjusted the heater from blowing up to blowing across the bottom on a bottom shelf. I will need to install small fans to take air from above and shoot it down to maintain a constant heat.

I could prob. take out the fermwrap heater, but the 200watt heats up the box quite well. I think for fun I will attempt 115F.

I have cooler temps on the bottom with condensation. I need much less water :slight_smile:

I seals up quite well. I have some picks. Gonna steam some rice tonight and start a batch to see what happens.

Probably taste like pine :wink:

Here are some pics. Koji Box in Operation

Hopefully the cotton cloth doesn’t have basement mold spores…
The rice is on a aluminium cookie sheet wrapped in a coarse cotton sheet cut-out.

The 200 watt heater is on the bottom and is temperature controlled.

The fermwrap just heats a tray full of pearlite and some water.

I end up getting a little condensation on the walls, but can easily maintain 110F internal temperature.
Currently set for 100F.

The crappy hygrometer says I can get around 80%.

Will see how it turns out in a few days.

Smartly done! I am very interested in seeing how it turns out.


Updated the shared google drive. Pics from IMAG0483 on are pics of the koji.

Will start the moto tonight with it, as well as make more koji with the Vision spores. I have a miso project on standby as well…

Oh, and the 115F didn’t work. Looks like 104F is about the highest it will go/maintain. Another 200 watt heater would make it work.

I was fairly surprised with this batch. Growth was very uniform and it didn’t get too wet or dry (other than the initial growth). No green/yellow. It was basically done at the 40 or so hr mark. I was afraid to let it go too long.

The air flow inside seems to be good. I can’t seem to get above 85-88% humidity. The door being the thinnest condensation was forming on it as well as the staples fastening the bubble insulator.

Looks like I will need to add a dampened cloth on top for 12 hrs or so.

The one thing I noticed, I could smell the koji before i could see it grow. Maybe I should remove the moisture at smelling the koji?

Nice box Dray, I had same issues with rice drying out with a fan no matter what the humidity was. If you lower humidity at the end of the cycle the koji grows into the rice deeper.

2nd batch of koji using vision spores. They are little bit older, being kept in the fridge but they still work.

Definite difference between sake spores from Akita Konno. The Konno spores make for much brighter white and more close to the grain. The vision spores are a slight yellow-tan/white. They both smell pretty much the same with a little more cheese/body odor-ish going toward Vision. I’ve always picked up a body odor like smell when growing koji. Not the offensive ‘you stink!’ kind, but a reminiscent light twang mixed with cheese, and chestnuts.

I use a plain cotton cloth cut into 1 yard squares, and use them as covers. This time I used a spray bottle and got the top wet/moist with water for the first 36 hrs. Really helped cut down on the dry rice pieces.

My steaming technique seems to be a making not enough wet steam. The rice gets well gelatinized, but prob. should absorb a little more water in the process. They seem a little dry.