日本酒を語る

Talk about sake

2021.07.09

Knowledge

Off-Flavors in Sake

One of pleasures of sake lies in its delicate and diverse aroma. Refreshing aroma of new sake is certainly good, but matured aroma that has been developed through aging has richness, profoundness and complexity to offer a different kind of appeal. However, if sake is not properly stored, such wonderful aroma will inevitably deteriorate. For instance, if sake is stored at high temperatures for long time, the aroma changes into sour smell to become off-flavors of aged sake called hineka. What’s more, exposure to sunlight or fluorescent light for even a few hours will cause deterioration due to the effects of UV light and develop a burning smell, namely a light-struck smell. Therefore, we need to carefully handle not just clear bottles as they are most susceptible to UV light but also colored bottles. Another damage is acid smell caused by unsanitary sake vessels. To prevent such damage, proper storing and cleanliness are essential, such as wrapping in newspaper and keeping in the refrigerator.
In old days, off-flavors used to be generated in the process of brewing, such as yogurt-like odor called tsuwarika, literally meaning morning sickness smell, which arises due to contamination caused by lactic acid, or rubber smell deriving from contact with rubber hoses, etc. However, with the advancement of technologies, there is virtually no such odor now. Sake brewing industries are continuously developing measures against off-flavors, which can be seen from the news in 2017 that they succeeded in developing yeast that is resistant to heat and generation of hineka. Even if sake deteriorates, it may taste good again if you let it mature again, but after purchasing, it is better to keep it from deteriorating as much as possible