@rettus360
This is a duplicate message that I sent to loriesco, but I wanted to make sure you saw it.

I would suggest looking at an 8 minute video by "Natto Dad" which helped me ger started many years ago. He experimented for a year before developing a method for good natto. If you are interested after viewing the video, let me know and I will give you my "fine tuning" tips that I do. It is a 3 day process from soaking soybeans to the final fermenting.

Natto is known to have a strong smell and a stringy, slimly texture, which is the "good stuff". If you have not had natto before, it would be good to try some so you know what natto is. You can obtain some from an Asian food store in their frozen section. As with most foods, frozen is not as good as fresh and the only place I know of to purchase fresh natto in the US is New York Natto, which I use for the starter in my batches. The link is: https://www.nyrture.com/order-natto

The owner is amazing with a PhD in microbiology. It is pricey at $13 to $15 a jar and the shipping is expensive because they ship by air in large ice pack but the shipping cost does not increase with larger orders so I order 12 and freeze most of them. It arrives quickly and cold. A minimum order of 4 jars is required. But I only use a 1/3 cup of the New York natto as a starter for a batch that lasts me a couple weeks, so overall it is a reasonable cost.

I feel natto has been a major factor for me with controlling my psoriatic arthritis without being on meds. My GP calls me "Amazing" and I am 81. Let me know what you think and I would be glad to further discuss my experience.