Sake is produced with no preservatives
Sake is unfortunately perishable, and quick to spoil. The reason why sake is high in alcohol concentration compared to other alcoholic beverages worldwide is the result of accumulated technical renovations in an effort to best preserve sake. However, the greatest obstacle to sake preservation, “hiochi bacteria” (lactic acid that spoils sake) could not be defeated despite high alcohol concentrations. Therefore, since the Edo Period, tradition dictates sake is brewed during the winter season to be “heat treated” in May. Early into the Meiji Era (1868 ~ 1912), the heat treatment timing and technology remained fundamentally unchanged, and by the early Showa Era (1926 ~), sake was poured directly into large kettles and directly heated.
However, the direct application of heat practiced at the time was merely a technique generated from many years of sake brewing experience, and the mechanism of sake spoiling due to the “hiochi bacteria” was not yet scientifically proven. Also, since sterilization was conducted in wooden barrels not fully concealed, then stored, even the heat application was not a thorough countermeasure to eradicate the hiochi bacteria. Scientific research into sake production started in the Meiji Era, bringing a remarkably quick countermeasure to resolve spoilage that materialized as a preservative and became widespread.
Chemist Oskar Korschelt, who arrived in Japan in 1876 and served as a chemistry professor at the University of Tokyo’s Faculty of Medicine, had previously taught at a beer factory in Germany where he had already succeeded in preserving beer by adding salicylic acid. Korschelt was first to recognize the hiochi phenomenon in Japanese sake production, and announced in 1879 that adding salicylic acid as preservative could prevent spoilage during the sake production process, a breakthrough considering sake breweries nationwide (26,171 breweries across Japan in 1879) were battling the hiochi bacteria at the time.
Afterwards, salicylic acid continued to be used long-term as a preservative to suppress spoilage by hiochi bacteria, unique to Japanese sake. However, as complete sterilization was made possible by heat treatment sterilization device and as disinfection device became widespread, breweries and sake production facilities also became sanitized, repealing the designation of this additive as food preservative in 1975, making this additive obsolete. Full-scale research on the hiochi bacteria presumably started in 1906, however, its propagation discovered to be caused by “hiochic acid” contained in sake was discovered approximately fifty years later in 1956.
However, the direct application of heat practiced at the time was merely a technique generated from many years of sake brewing experience, and the mechanism of sake spoiling due to the “hiochi bacteria” was not yet scientifically proven. Also, since sterilization was conducted in wooden barrels not fully concealed, then stored, even the heat application was not a thorough countermeasure to eradicate the hiochi bacteria. Scientific research into sake production started in the Meiji Era, bringing a remarkably quick countermeasure to resolve spoilage that materialized as a preservative and became widespread.
Chemist Oskar Korschelt, who arrived in Japan in 1876 and served as a chemistry professor at the University of Tokyo’s Faculty of Medicine, had previously taught at a beer factory in Germany where he had already succeeded in preserving beer by adding salicylic acid. Korschelt was first to recognize the hiochi phenomenon in Japanese sake production, and announced in 1879 that adding salicylic acid as preservative could prevent spoilage during the sake production process, a breakthrough considering sake breweries nationwide (26,171 breweries across Japan in 1879) were battling the hiochi bacteria at the time.
Afterwards, salicylic acid continued to be used long-term as a preservative to suppress spoilage by hiochi bacteria, unique to Japanese sake. However, as complete sterilization was made possible by heat treatment sterilization device and as disinfection device became widespread, breweries and sake production facilities also became sanitized, repealing the designation of this additive as food preservative in 1975, making this additive obsolete. Full-scale research on the hiochi bacteria presumably started in 1906, however, its propagation discovered to be caused by “hiochic acid” contained in sake was discovered approximately fifty years later in 1956.
日本酒に防腐剤は一切使われていない
日本酒は、残念ながら非常に腐りやすい酒である。日本酒のアルコール濃度が世界に例を見ないほど高いのも、なんとか腐りにくい酒を造ろうと技術革新を重ねてきた結果という説もあるほどだ。しかし、日本酒の最大の敵である「火落菌」は、これほどアルコール濃度を高めても撃退できなかった。そのため江戸時代以降、寒造りの酒は八十八夜前後に「火入れ」することとなっていた。明治に入ってからも火入れの時期や技術は基本的に変わらず、昭和の初期頃までは、直釜と呼ばれる大きな和釜に直接酒を入れ、直火で加熱していた。
ただし、当時の火入れはあくまで永年の酒造りの経験から生まれた知恵であり、「火落菌」による酒の腐敗のメカニズムが科学的に解明されていたわけではなかった。しかも、殺菌が不完全な木桶で仕込み、貯蔵を行なっていたわけだから、火入れをしていても「火落ち」に対する完全な対策とはいえなかった。 日本酒造りに科学のメスが入れられたのは明治時代になってからだが、
この腐敗に対する対策は意外と早く、防腐剤という形で普及することになった。明治9年に来日し、東京医学校（現・東京大学医学部）の化学教師を勤めたオスカー・コルシュルトは、ドイツでビール工場の技師をしていた人だが、すでにサリチル酸の添加によるビールの防腐に成功していた。 コルシュルトは日本酒の火落ち現象にもいち早く気づき、サリチル酸を防腐剤として添加すれば腐造を防げると発表した。明治12年のことである。 全国各地の酒造場（9年当時で全国に26,171場あった）で火落ちが頻発していたことを考えれば、まさに画期的なことだった。
サリチル酸はその後も、日本酒特有の腐敗菌である火落菌の生育抑制を 目的とする保存料として長く用いられてきた。しかし、完全な殺菌のできる火入れ殺菌機や除菌装置が普及し、酒蔵や製造設備自体も清潔になったことで添加の必要がなくなり、昭和44年以後は業界の自主規制によって使用が自粛された。昭和50年には食品添加物としての指定も取り消されており、現在はまったく使用されていない。 ちなみに、火落ち菌の本格的な研究は明治39年から始まったとされるが、その繁殖が日本酒に含まれる「火落酸」という成分に関わっていたことが解明されたのは、ちょうど50年後の昭和31年のことだった。
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