The sake looks murky, but the aroma and flavour are superb. The mouthfeel is a little creamy to start with, but there's also a lot of fizz too, so it's definitely still fermenting.

During this time the koji will start converting the rice to sugars to feed the yeast, letting it slowly build up and not stressing either the kojinor the yeast.
As we go on we'll add more koji and more rice.

Then we stir in 575ml of water and our yeast before popping it back into the incubation chamber with is now acting as a warm room set to 24c where we'll leave it for a week.

Now we mix in the steamed rice with with 115g of our koji.

Now the rice is steamed we let it cool down for a bit.
We want it to be about 25c to 30c

And now we pop it in the steamer for just over an hour.

We've rinsed and soaked 340g of premium sushi rice (can't get sake rice so have to make do for this batch).
Same rinse and soak method as for the koji.

Mostly by help from @erwinh.bsky.social 🤣

And after 53 hours of innoculation we now have enough koji for a 50l batch of sake.
It's possibly gone a little far, which is why there's a yellow tint to it, but that's likely down to the humidity issues I was having.

I knew little to nothing about biochemistry before starting brewing, and have learned so much since!

(deleted first reply as I misunderstood your post 🤣)

From what I can understand, you get heat generation at a small scale as well as large scale.
With fermentation it changes depending on scale, but doesn't seem to with innoculation.

...I could barely see the rice grains and koji on them so had to try and take an in-focus close up photo to check on progress 🤣

My innoculation chamber *really* needs some dehumidifier set up. It's currently got a humidifier in there, but that was only really in use for the first few hours, since then I've been having to prop the door open occassionally to keep the humidity down.

My eyesight is really getting bad as...

We're now 44 hours into innoculation, and we'll check it again in another 4 hours to see if it's time to remove the trays from the incubation chamber and put them into the fridge to stop any further, unwanted growth before we then use this to make sake!

Looking at the rice this morning, and we have koji!

18 hours sat in the inoculation chamber at 30c and 85% humidity, and we take the trays out to give the rice a good mix.

Time to mix the spires in, then into the inoculation chamber it goes for 18 hours!

That's the first batch of steamed rice now spread out and cooling.
We want to get this down to about 40c before adding our spores.