(Note: edit(s) are at the end of this thread.)
I used the following ingredients:
Wild black rice
Adzuki beans
Mung beans
Chickpeas (garbanzo beans)
Black beans
I soaked, drained, then sprouted all of the above. After sprouting, I put everything in to a slow cooker, and cooked them for 9.5 hours. Also, I read somewhere that a sweet potato can help with fermenting natto. Is this true? I'm sorry that I can't be more precise. I didn't pay any attention to the article, and simply decided to go ahead and use one, and hope for the best. So, alongside the above ingredients, I put one whole unskinned sweet potato in to the slow cooker.
After 9.5 hours had elasped, everything seemed cooked, including the sweet potato. I used a store bought natto packet for the starter culture. Before applying it to the above cooked ingredients, I added hot water to it, and also mixed in a couple of probiotic capsules called Prescript Assist. (Contains Bacillus subtilis.)
I put the drained cooked beans in to two shallow dishes, and also put one third of the sweet potato in to each dish. I mixed everything up well, including putting one tablespoon of my mixed up starter culture in to each dish. I then put the dishes in to a proofer device for 23.5 hours, at a temperature of 38C.
After 23.5 hours, I checked the dishes - please see the photo below. To my untrained/newbie natto eye, it looks fine.
However, the potential problem might be when I stirred the fermented food, because I could immediately see that the food looked soggy. Please see the photo below.
Perhaps the sogginess was caused by the sweet potato? Perhaps I used too much? Perhaps I didn't need to use it at all? Perhaps it won't matter anyway, because before stirring, it looked "nicely fermented", with that fermented "glazed" look.
However, when I stirred the food and saw the sogginess, I couldn't see much stringiness. However, it's possible that the stringiness has been "hidden" by the sogginess? The only thing that concerns me is that I really hope it contains "stringy nutritious goodness". If I can't see the stringiness, because it has been hidden by the sogginess, then I really don't care. However, if the stringiness really isn't there at all, then I will be really disappointed.
Any thoughts or comments would be greatly appreciated. Thanks a lot! Please note as this experiment has only just been done, I have put the fermented food in to jars, and in to the fridge. I haven't tasted it yet. It certainly doesn't smell bad. I'll taste test it in a couple of days time, and report back..
EDIT #1 - I just tasted it, and wow, the "sauce" tastes great! It tastes of coffee/caramel. I reckon most of the sauce is simply the sweet potato. Although it seems to have messed up the characteristic stringiness, I really don't think it's negatively affected the fermentation process, because it really tastes like the store bought natto. However, not all is well, because the beans themselves are very surprisingly hard. I think this must be due to the way in which I cooked them: sprouting them first, and then slow cooking them. I think this hardens the beans. However, I put them in a blender, and whizzed them up, and added them to other food that I am eating, and it seems just fine - both in terms of taste and texture.