Archives for posts with tag: Heat chamber

During the 48 hours of koji cultivation one must take care of it.

I open the heat chamber every morning and evening if not more often. I check the moisture (if the inoculated rice is getting too wet or too dry), the thermometer to make sure that the temperature is around 30 centigrade and then add air by paddling the mass back and forth a few times.

Then back into the warmth for a while.

The koji incubates for 2 days at 30 degrees centigrade in the heat chamber. 

Air must be mixed in and moisture spread twice daily. 


I’ve had a lot of questions about my heat chamber. I found it in a dumpster about 40 years ago. It was made for keeping workplace lunch boxes warm, and have since been superceded by microwaves. The company that made it doesn’t make them anymore. 

Similar heat cabinets can be found new or used on the internet. A laboratory supply company, for instance, would have such. 

Or you could easily make your own as I did  when I started. All you need is a box or cabinet of a proper size,  a low energy lamp and a thermometer. Just check the temperature often and turn the lamp on or off to keep it fairly close to 30 degrees (between 25 and 35 is good enough).