Sake
Rice. Water. Koji mould. A simultaneous saccharification and fermentation that no other major drink category uses. Japan's national drink — and the world's most misunderstood fermented beverage.
Codex Definition
Sake (日本酒, nihonshu — "Japanese alcohol") is a fermented rice beverage produced in Japan from rice (Oryza sativa), water, koji mould (Aspergillus oryzae), and yeast (Saccharomyces cerevisiae). It is often called "rice wine" but is biochemically closer to beer in production method — both convert grain starch to fermentable sugar before yeast fermentation. What makes sake biochemically unique: it uses simultaneous saccharification and fermentation (SSF) — the koji mould continuously produces amylase enzymes that convert rice starch to glucose at the same time as yeast ferments the glucose to alcohol. This parallel process is called heiko fukuhakko (並行複発酵). Typical ABV after fermentation: 18–20% — the world's highest naturally fermented alcohol level, possible because the gradual glucose release by koji prevents yeast from being inhibited by excessive sugar. Most sake is then diluted with water to 14–16% ABV for bottling. Sake production is regulated by Japan's National Tax Agency (NTA), which classifies sake into designated premium grades based on rice polishing ratio (seimaibuai).
The sake classification system — seimaibuai and category
The most important parameter in sake classification is the seimaibuai (精米歩合) — the percentage of the original rice grain remaining after polishing. Rice is polished (milled) to remove the outer layers of the grain, which contain proteins, fats, and minerals that, if left in the sake, produce harsher flavours. Higher polishing (lower seimaibuai number) produces more delicate, aromatic, clean sake; lower polishing (higher seimaibuai) produces richer, more umami-driven sake.
| Type | Seimaibuai | Alcohol addition? | Character |
|---|---|---|---|
| Futsushu (普通酒) | No minimum | Permitted (up to 50% of volume) | Standard table sake (~75% of production). No premium designation. |
| Honjozo (本醸造) | ≤70% | Small amount permitted (up to 10% of rice weight in pure alcohol) | Light, dry, approachable. Small alcohol addition lightens texture, increases aroma. |
| Junmai (純米) | No minimum (in current regulations) | Not permitted (junmai = "pure rice") | Richer, more umami-driven, full body. No added alcohol. More rice-forward. |
| Ginjo (吟醸) | ≤60% | Small amount permitted | Fruity, floral, delicate. Low-temperature fermentation produces ginjo-ka (吟醸香) — fruity esters including isoamyl acetate (apple/pear) and ethyl caproate (apple). |
| Junmai Ginjo (純米吟醸) | ≤60% | Not permitted | Ginjo character + pure rice. Fruity and complex. |
| Daiginjo (大吟醸) | ≤50% | Small amount permitted | Very highly polished. Most delicate, most aromatic. The highest prestige designation. Very fruity, floral, transparent. |
| Junmai Daiginjo (純米大吟醸) | ≤50% | Not permitted | Peak designation. Maximum rice polishing, no added alcohol. Complex, expensive. The premium benchmark. |
Sake Depth
The full brewing science: koji and multiple parallel fermentation, the seimaibuai polishing ratio, the tokutei meishoshu premium grades, the kimoto/yamahai/sokujo starters, sake rice and water, and the brewing steps.
Junmai & Honjozo
The workhorse sake designations. Junmai (pure rice, no added alcohol), Honjozo (small alcohol addition). Rice-forward character. Koji biology and SSF science.
Ginjo & Daiginjo
≤60% (Ginjo) and ≤50% (Daiginjo) seimaibuai. Low-temperature fermentation. Ginjo-ka fruity ester chemistry (isoamyl acetate, ethyl caproate). The aromatic peak of sake.