Miso

Fermented from Glycine max

Miso is a fermented paste made from cooked soybeans, koji, and salt, and it works as a two-stage fermentation.¹ First the mold Aspergillus oryzae is grown on rice or barley to make Koji; then the enzymes that koji produces, chiefly proteases and amylases, dismantle the protein and starch in the beans into amino acids and simple sugars. Wild yeast, lactic acid bacteria, and acetic acid bacteria add to the flavor as the paste ages.¹

Its history traces a Chinese-Japanese exchange. When Chinese monks brought jiangs, fermented bean pastes, to Japan in the sixth century, the jiang evolved into miso, and the liquid that pooled on top of the paste became known as tamari.² For most of its history the work was slow and physical: beans were cooked, crushed, mixed with salt and koji, packed into cedar vats, weighted down to exclude air, and aged for one to three years.³

Regional styles differ mainly in salt and time. White miso, preferred in western Japan, is sweet, lightly salted, and ferments in about a week; Edo miso around Tokyo is low-salt and quick; Sendai and Shinshu misos are saltier and age a year or more; mame miso, made from soybeans alone, ferments for about two years and keeps especially well.⁴ Harold McGee groups miso with soy sauce in the family of traditional fermented soybean seasonings, both rich, savory, and salty.⁵

The Northeast has its own miso tradition. South River Miso Company in Conway, Massachusetts has made wood-fired, certified-organic miso since 1979, turning beans and regional grains into everything from azuki bean miso to dandelion-leek variations.⁶ The experiments in this notebook — barley soy miso, grits miso, and others — continue that thread, treating miso as a destination for local grains and beans.