Name: Royal Sushi & Izakayas Hakkaisan Nama Genshu Recipe
Cook time: 36 h
Total time: 36 h
Yield: 50 servings
Cuisine: Japanese
Ingredients: 6 kg Heirloom sake rice (Yamada Nishiki or local heirloom variety), polished to ~60%; 1.8 kg Koji rice (steamed rice inoculated with Aspergillus oryzae), freshly made; 13.5 L Brew water (soft, low-mineral, neutral pH); 1 L Shubo (yeast starter) - if using prepared starter instead of making from scratch, high-attenuation sake yeast culture; 1 pack Sake yeast (example: K-701 / Kyokai No. 701) - dry or liquid rehydrated; 6 ml Lactic acid (food grade) - to adjust pH in shubo if building from scratch; 5 g Fermentation nutrient (optional, yeast nutrient specialized for sake); 0.5 L Cold, filtered water for final adjustment (if needed); 100 ml Sanitizer (no-rinse) for equipment

Nama Genshu bright, mochi rice, complex, dry, fresh cut herbs

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If you are starting from unpolished heirloom rice, polish rice to approximately 60% of original grain weight. Rinse polished rice repeatedly in cold water until washing water runs clear (typically 4–6 rinses) to remove excess surface starch. Drain and soak rice for 30–60 minutes, depending on ambient temperature (longer in cold conditions).

Polish and wash rice

Steam the soaked, polished rice until cooked through but still slightly firm in the center (approx. 45–60 minutes in a steamer). For koji production, reserve a weighed portion: 1.8 kg of steamed rice for koji cultivation and the remainder (4.2 kg) for moto and main mash.

Steam rice

Cool the 1.8 kg steamed rice to about 30–32°C on a sanitized tray. Inoculate rice evenly with Aspergillus oryzae starter spores (koji-kin) and keep at 30–32°C with high humidity (~90%) for 40–48 hours. Turn and mix rice every 6–8 hours to prevent overheating and to encourage even mold growth. After 40–48 hours, when rice is covered with white hyphae and aromatic nutty, fruity koji aroma develops, chill immediately to stop enzyme activity and store at 4°C until use.

Make koji (if not using pre-made)

Option A (sokujomoto quick starter): In a sanitized 2–3 L vessel, combine 500 g steamed rice (cooled), 500 ml brew water, 150 g koji (finely mashed and mixed), 6 ml lactic acid, and rehydrated sake yeast (per package instructions). Maintain temperature at 18–20°C. Stir gently twice daily and hold for 5–7 days until vigorous fermentation and a pleasant yeasty aroma are present.

Option B (yamahai / kimoto traditional starter): Build the starter over 10–14 days by alternating additions of steamed rice, koji, and water, allowing natural lactic fermentation and longer time for lactic acid bacteria to develop. This produces stronger umami and nutty aroma in the final sake. For a rice-forward, bold profile (like Hakkaisan Nama Genshu), yamahai yields deeper umami; expect longer time and more monitoring.

Prepare shubo (yeast starter/moto) — traditional yamahai or sokujomoto approach

Sanitize a fermenter of at least 25 L. Keep all equipment cool and sanitized. Conduct a san-dan (three-stage) addition over four days: Day 1 (Hatsuzoe): Combine 1.4 kg steamed rice (cooled), 600 g koji, and 2.5 L brew water with 250–300 ml of active shubo. Hold at 12–15°C.

Day 2 (Nakazoe): Add 1.4 kg steamed rice, 600 g koji, and 3.5 L water. Gently mix to incorporate. Maintain temperature 12–15°C.

Day 3 (Tomezoe): Add remaining steamed rice (4.2 kg - 2.8 kg used above = 1.4 kg), 600 g koji, and 3.5 L water, or split remaining quantities so total rice used reaches 6 kg and koji reaches 1.8 kg, and total water reaches approximately 13.5 L. Final moromi consistency should be porridge-like. Stir carefully to avoid introducing oxygen after initial days.

Prepare main mash (moromi) — three-stage method

Maintain fermentation temperature at 12–15°C for 18–28 days for a clean but bold, rice-forward profile. Stir the mash gently once or twice daily during the first week to homogenize and then less frequently as fermentation slows. Monitor gravity (or measure specific gravity / refractometer) and aroma: expect a nutty, umami-rich scent developing after 7–14 days. If fermentation slows prematurely, consider adding small nutrient boost (5 g) or slightly raising temperature by 1–2°C for a few days.

Fermentation

When primary fermentation is complete (attenuation plateaued and solids have compacted, typically 18–28 days), separate the sake from the lees (kasu). For small-scale, use a mesh bag or muslin lining inside a basket press and apply gradual pressure until clear sake runs. Collect first runs (shizuku) separately from later press fractions if desired for quality sorting. Aim to collect clear, rice-forward liquid with pronounced nutty-aromatic notes.

Pressing

Since this recipe targets a 'Nama Genshu' style (unpasteurized, undiluted), skip pasteurization and dilution. Instead, chill the freshly pressed sake to 0–4°C immediately to preserve fresh aromatic (nama) character and slow microbial activity. For stability, filter lightly (paper or coarse cartridge) to remove large particulates, but avoid heavy filtration that strips aroma. Keep bottled sake refrigerated at all times.

Cold stabilization and pasteurization

Sanitize bottles and caps. Fill bottles in a cold room or over ice to keep temperature low. Leave minimal headspace, cap tightly, and label with brew date. Store bottles at 0–4°C. Because this is genshu (undiluted), resulting ABV will be higher than typical (likely 18–20%); consider blending small batches with chilled filtered water if you prefer lower ABV, but traditional Hakkaisan Nama Genshu remains undiluted.

Bottling

Allow bottles to rest 2–6 weeks chilled to let flavors integrate; drink within 6–12 months for freshest 'nama' characteristics. Serve chilled (5–10°C) to highlight nutty aroma, rice-forward umami, and dry finish. If you used a yamahai-style moto, expect a bolder, earthier umami and slightly more acidity; sokujomoto will be cleaner and brighter.

Aging and serving

Heirloom sake rice (Yamada Nishiki or local heirloom variety), polished to ~60%

Koji rice (steamed rice inoculated with Aspergillus oryzae), freshly made

Brew water (soft, low-mineral, neutral pH)

Shubo (yeast starter) - if using prepared starter instead of making from scratch, high-attenuation sake yeast culture

Sake yeast (example: K-701 / Kyokai No. 701) - dry or liquid rehydrated

Lactic acid (food grade) - to adjust pH in shubo if building from scratch

Fermentation nutrient (optional, yeast nutrient specialized for sake)

Cold, filtered water for final adjustment (if needed)

Sanitizer (no-rinse) for equipment

Hakkaisan Nama Genshu

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Make Hakkaisan Nama Genshu Recipe in just 36h . nutty aroma, heirloom rice, bold, rich, rice-forward, umami, dry

Hakkaisan Nama Genshu Recipe

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