Probiotics and Natto

I have been wanting to experiment making my own probiotics due to the rising cost of store bought probiotic foods and my probiotic pickles went so well I want to try making other probiotic foods. I am investing in a yogurt machine next month.

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I just stumbled on this video that tells you how to make natto. I think I also want to try to make natto by cooking the soybeans in my pressure cooker and then using the yogurt machine to culture the beans. I need to find some natto to inoculate the beans with which means I will probably have to wait until the next time I can make it to the Asian import store in Medford being that there are no local Asian import stores.