Soy sauce with beer yeast as koji?

Yep! Exactly what you’ve read!
I’ve read some people talking here and other places about making beer with koji, to see what it makes and all.
But… what if we go the other way around?
From what I’ve got, Koji is there just to be a know and safe culture to ferment the soybeans.
So… what if I make it with beer yeast?

I can get Koji, but it’s hard for me since the shipment to my region in Brazil takes really long and because of this is really expensive, so I want to try with some cheaper before trying the real stuff.If you guys think it’s possible, how should I try it? Just pour the liquid starter over the steamed and still wet beans??

hahaha I’m laughing here just for thinking about what the result could be

I was under the impression that Koji was required to convert the starches in the beans into fermentable sugar. I’m not super familiar with soy sauce production, and I’m assuming that there is a way to convert the starches with other means aside from Koji (amylase enzyme, possibly?). I think you still need to find a way to manage the part of the process that koji is traditionally used for. From there, you may be able to ferment with beer yeast, but i don’t think that yeast alone is sufficient.

Soy sauce is already fermented I believe

I guy told me that from what he knows, you are right about the starches. But if I’m doing the soy sauce with east, I would need something to break the starches as Koji does, so he suggested to find some amylase enzymes.

From what I’ve got, it’s possible.
And it will be a fun ride! hahah

yes, its koji (aspergillus oryzae) or a few other moulds that break it down.

the korean way of soy sauce production traditionally is to make blocks of compressed soybean paste that are very hard, let them dry out and let the moulds work on them over months. then the fermented blocks have water added to them in a pot and soy sauce is sort of created. japanese method may be different.

but yeah, basically its taking soy bean paste - having the mould break down the carbohydrates/beans into something fermentable and the yeast does that job.

its been quite a while so i’ve forgotten.

using enzymes is a cheaper/faster way to do it but the taste difference is pretty clear.

commercial soy sauce has improved in north america INSANELY since i was a kid. it used to be super industrial, basically salt in caramel colour water with soy essences. very different now, definitely try out some quality soy sauces