Tauco

Step 1: Soak 1 ⅛ lb dried yellow soybeans in plenty of cold water for 12 hours, until plump.

Step 2: Rub the beans between your hands in the water to slip off the skins, then swirl and pour off the floating skins; repeat until most are gone.

Step 3: Boil the beans in fresh water for about 60 minutes, until soft enough to crush between finger and thumb but still holding their shape.

Step 4: Drain well and spread on a clean tray. Pat with a clean cloth and leave until just warm (about 95°F) and only slightly moist on the surface.

Step 5: Dry-roast 2 ⅛ oz rice flour in a pan over a low heat for 5–8 minutes, stirring, until ivory and toasty-smelling. Cool, then mix with oz koji spores (Aspergillus oryzae, for miso or soy sauce) and dust over the beans, tossing until each is coated.

Step 6: Spread the beans 2–3 cm deep on a tray lined with a clean cloth or banana leaves, cover with a cloth (not plastic) and keep at 28–90°F, for example in an oven with only the light on, for 2–3 days. After about 24 hours they warm up by themselves; break them up and spread them thinner so they do not overheat.

Step 7: Check twice a day. Normal: a white fluffy mycelium that knits the beans together, later turning pale yellow-green as the koji forms spores, and a sweet, chestnut-like smell. Discard the batch if you see black, pink, red or orange patches, wet slime, or it smells strongly of ammonia or rot.

Step 8: Dry the moulded beans in the sun or in a 113°F oven for 3–4 hours, until the surface feels dry. Do not wash off the spores.

Step 9: Sterilise a 2-litre glass or ceramic jar and lid: wash in hot soapy water, rinse, then dry in a 250°F oven for 10 minutes (or in strong sun for a few hours). Cool completely; the jar, bowls, spoons and your hands must be bone dry.

Step 10: Dissolve 7 oz coarse salt in 1 litre water, boiled and cooled. Add the beans, stir with a clean dry spoon and cover with a cloth and loose lid. Leave in a warm, sunny spot for 3–4 weeks, stirring every day. Normal: the brine turns brown, a few bubbles rise and it smells like soy sauce; a flat white film can be skimmed. Fuzzy coloured mould or a putrid smell mean discard.

Step 11: Tip the beans and brine into a wide pan with 7 oz palm sugar (gula aren), plus 1 pandan leaf and ¾ in galangal if using. Simmer over a low heat, stirring often, for 30–40 minutes, until the sauce is thick, glossy and some beans have broken down.

Step 12: Remove the pandan and galangal and cool. Spoon into clean sterilised jars and keep in the fridge for up to 6 months, always with a clean dry spoon. Discard if mould, fizzing or an off smell appears.