Just a quick question… does koji die at 104 or 113?
Definitely not 104ºF, as I’ve had koji go well beyond that during the course of a couple batches. So, until tested thoroughly, let’s go with “koji dies at 113ºF.”
I’ve had it up around 114 pretty regular for quite a while without an issue. Don’t know the upper bound.
I asked the folks at Akita Konno to review a document on koji making that I wrote to go along with their “special ginjo” koji-kin that I am just starting to carry. Anyway, in this document I stated that if the temperature goes above 114F you should do something to bring the temperature down. They did not make any comment about that while they commented about possibly short steam times and roasted flour temperatures. I lowered it in my doc to 110F, but I wondered what they might say about the 114F, nothing.
Just received my Akita Konno ginjo koji spores! Very nice document with those Will. It appears I’ve been making the kind of koji that doesn’t completely cover, but goes in deep. About half the koji is that way, the other half fully covered, but 2/3 into the grain. I do have some grains completely solid white.
That would explain the bucket lid exploding off a few years back. I must had OVER 9000!!! enzyme power.
Good to hear the koji-kin made it.
Can’t wait to hear how it does for you; both the koji and the spores. :cheers:
While an organisms such as koji can survive at elevated temperatures close to the maximum of where growth is observed, you csn be certain that what the organism is doing at the different temperatures is not the same in most cases. Especially when the citical temperature where the cells capitulates is reached. So while koji may survive at 113F or higher does not mean necessarily that you will get nearly the same amount of living cells or cells that is programmed to do what you want them to do.
While this is not a direct answer I hope it still gave you something or at least gave someone something 
While an organisms such as koji can survive at elevated temperatures close to the maximum of where growth is observed, you csn be certain that what the organism is doing at the different temperatures is not the same in most cases. Especially when the citical temperature where the cells capitulates is reached. So while koji may survive at 113F or higher does not mean necessarily that you will get nearly the same amount of living cells or cells that is programmed to do what you want them to do.
While this is not a direct answer I hope it still gave you something or at least gave someone something
