I just realize something about mold:
Most molds are aerobic, they require oxygen. Koji mold used in making Sake, Miso, etc... is part of the Aspergillus genus of molds, which are highly aerobic.
Beer, on the other hand (once fermentation has begun), is a largely anaerobic environment.
If you wanted to use Koji in your beer, I'd suggest using it in your mash. I have read that it is most active around 140 degrees F, but will die off much higher than that.
Keep in mind, mold is a subset of the fungus kingdom. The yeasts which we use to ferment and mature our beer (including both Sach. and Brett.) are of the fungi kingdom. Not all fungus is aerobic, but it seems that molds are generally aerobic, which is probably one of the reasons they are never traditionally use to ferment beers.
Thanks for the info. I thought using the koji in the mash but I'm not going to for several reasons. First, I would lose any of the volatile flavors from the koji in the boil. Second, I would have to have a fairly good infection going to get a good effect from the koji. It might be interesting though to infect your mash at room temperature or close to it and let it sit around for a couple of days (3,5,7?) and then precede with the normal mashing process. Probably get very good conversion from it but, again, would lose any of the volatiles in the boil.
So this is my plan right now - first, I will make a starter for the koji by cooking up a couple cups of white rice and letting ferment for a couple days. Then I will cook up 2-4 pounds of either rice, wheat or oats. Right now I am leaning towards wheat but I am little concerned about all the extra crap it might leave behind. Not too concerned though. Next, I am going put the cooked grain into a bucket with the koji starter and some brett. and let the whole thing ferment for a while with a dry airlock on so that oxygen can still get in. After it ferments for three to seven days (I'll play this by ear or find some more Sake info) I'll make up a normal batch of beer, probably a mildish brown, and pitch it over the infected grain cake and ferment. Ta da!
One thing I am interested/concerned about with this whole process is the effect of having the live koji will have on the body of the beer. Since I will not be heating the koji cake, any of enzymes which the koji uses to break down the starches will still be present during the primary fermentation, which might break down the dextrins and such in the wort, leaving me with a very thin beer. Anyway, we shall see and to counteract this somewhat I'll mash the beer fairly hot (~158).
I will probably start this whole process the beginning of next week but I am going back to Seattle this weekend and the heather is blooming. I love me some heather beer!
Fresh heather >>>> dried heather, BTW.
And...many anaerobic molds & other organisms will kill
Yowser, I am going to be using commercially purchased koji which has been used for centuries to make Sake, soy sauce, miso, etc. I am not going to be scraping the black mold out of my shower and infecting my beer with it. Well, not yet, at least. Well not the black mold, there is this pink stuff...