Hojo Biden Yamahai Recipe

Polish and wash rice

If starting with unpolished rice, ensure a polishing rate appropriate for sake (50–70% remaining). Rinse the rice under cold running water until the rinse water runs clear to remove surface starch. Soak the rice in cold water for 45–60 minutes (longer for more-polished rice). Drain thoroughly.

Steam the rice

Steam the drained rice for 40–50 minutes until the grains are cooked through but still slightly firm at the center. Avoid boiling; steaming preserves texture for koji and fermentation. Spread steamed rice thinly on a sanitized tray to cool briefly to around 30–35°C (86–95°F).

Prepare koji

If making koji yourself, inoculate a portion of cooled steamed rice (1.25 kg) with koji spores and incubate at 30–32°C (86–90°F) for ~48 hours, turning periodically to ensure even growth until fragrant and covered in white mold. If using pre-made koji, ensure it is fresh and at room temperature before use.

Day 1 — Mix moto base

Sanitize your fermentation vessel. Warm approximately 3 liters of water to 30–33°C (86–91°F). In the vessel, combine 1.5 kg steamed rice (coarsely crumbled or in a sanitized muslin bag), 375 g koji, the warmed water, and 2–3 ml lactic acid (optional) to adjust pH. Stir thoroughly until a uniform porridge forms. The yamahai method traditionally allows natural lactic acid bacteria to develop, so omit lactic acid if you prefer a wholly traditional approach. Add 2 g of yeast nutrient if available. Cover with a breathable cloth and keep at 25–30°C (77–86°F).

Day 2–7 — Allow lactic fermentation (natural lactic acid development)

Every 12 hours for the first 3–4 days, stir the mash vigorously for 3–5 minutes; then reduce stirring frequency to once daily. This oxygenates the mash and encourages lactic acid bacteria (especially in yamahai). Maintain temperature between 20–30°C (68–86°F). You should observe a mild sour smell and some bubbling as lactic acid bacteria develop. If you added lactic acid at the start, this serves only to stabilize pH; the yamahai method relies on native bacteria so expect slower pH drop than modern sokujo moto.

Day 7 — Inoculate with yeast

When the mash smells pleasantly sour (not rotten) and has reached a slightly acidic state, add the brewer's yeast (10 g). If you have a small moto starter from a previous batch (100 ml), add it now to boost yeast activity. Stir gently to incorporate. Continue keeping the vessel at 18–22°C (64–72°F) to allow yeast to take hold. Over the next 2–4 days you should see fermentation activity increase (bubbling, foaming beginning).

Day 0 of moromi — First addition (Hatsuzoe)

In a larger sanitized fermentation vessel (10–20 L), combine 3.5 kg steamed rice (cooled to ~30°C), 375 g koji, and 6 liters of water. Add the entire moto starter (from previous section) to this mixture and stir gently to homogeneity. Keep temperature controlled at 12–18°C (54–64°F) for a slow, clean fermentation. Cover with breathable cloth and allow active fermentation to continue; you should see steady CO2 release within 24–72 hours.

Day 3 — Second addition (O-zoe)

After 2–4 days of active fermentation, add the second batch: 1 kg steamed rice, 375 g koji, and 3.5 liters of water warmed to ~25°C. Stir gently to incorporate. This builds the mash up and supplies more starch for koji enzymes and yeast to work on. Maintain fermentation temperature at 12–18°C and stir once daily to keep solids suspended and oxygenated slightly.

Day 7 — Final addition (Tomezoe)

Seven days after the first addition (or when the mash shows vigorous activity and has partially thinned), add the remaining 1 kg steamed rice and 125 g koji with 2 liters of water. Stir thoroughly to mix. At this stage, the total volume should be approachable in the vessel with space for foam. Continue fermentation at 10–16°C for the next 2–3 weeks. Stir every 1–3 days, more often early on to prevent clumps and ensure even fermentation.

Monitoring

Monitor smell and activity: yamahai will display a more complex, lactic/silky acidity and occasional farmhouse funk. Use a hydrometer if desired to track specific gravity; expect a gradual drop over 2–4 weeks. Keep the vessel covered but not airtight to allow traditional lactobacilli and other organisms to breathe.

End of fermentation

After 2–4 weeks (when bubbling slows significantly and gravity stabilizes), stop fermentation. Let solids settle for 24–48 hours in a cool place (5–10°C if possible) to allow clearer sake to separate. Optional: rack off clear liquid above the lees into a sanitized container.

Pressing (naka or fune style)

Press the moromi through a sanitized mesh bag or press (if available) to separate sake from kasu (sake lees). If you used a muslin bag, squeeze slowly with sanitized hands or press plate to extract as much liquid as practical without forcing solids through. Collect the free-run first for higher quality; press-run yields secondary quality but still fine for home purposes.

Filtration & settling

Allow the pressed sake to sit in a cool, sanitized carboy for a few days to drop fine sediments. If desired, cold-settle at 0–5°C for several days to further clarify. Siphon (rack) off clear sake from lees into another sanitized vessel.

Pasteurization & bottling

To stabilize the sake, pasteurize gently by heating to 60–65°C (140–149°F) for 15–20 minutes in a water bath while stirring gently, then cool quickly. Alternatively, you may choose to leave it namazake (unpasteurized) and keep refrigerated. Bottle into sanitized bottles, leaving appropriate headspace, and cap. Age bottles for at least 1–3 months to allow flavors to marry; yamahai often improves with 6–12 months of aging.

Thoroughly sanitize all equipment after use. Save a small portion (100 ml) of healthy moto as a starter for future batches if desired. Tasting notes: Expect a full-bodied, earthy, lactic-acid-accented sake with richer umami and gentle acidity. Adjust water profile, rice polishing, and fermentation temperature to refine flavor across batches.