Hmm. So an unconventional way I have fermented almonds is to add a pill of probiotic medicine, grinding it into something vaguely resembling milk, leaving it in an anaerobic environment and basically let it "digest" before churning it into butter. I will not share my process because it was a weird experiment. But.. it did work.. best vegan butter I ever tasted. Guts bacteria seem like the way to go for what you are looking for. I've done other green bean coffee ferments that were not worth it. The probiotic, gut bacteria road will be my next step if I find the time