Miso is a fermented paste made from a mash of cooked soybeans, koji and salt. Like vinegar, miso is a two-stage fermentation. First the fungus Aspergillus oryzae is grown on either rice or barley to produce koji (read the koji chapter page 211) for a deeper understanding of this process). Then the powerful enzymes produced by koji, namely protease and amylase, are harnessed to dismantle the protein and starch in another substrate (traditionally soybeans), cleaving them into amino acids and simple sugars, respectively. Wild yeast, lactic acid bacteria and acetic acid bacteria also add to the fugue of flavours as the miso ages.
My plan is to use a repurposed electric oven with a RS I will cast using refractory materials.