Preservation
The Quality of Sake:
Knowledge and Know-How to Maintain Quality
Based on scientific basis obtained from research results of the NRIB,
this video introduces how to maintain the quality of Japanese sake.
Pick up Sake Terminology
The sake terminology is explained in the video,
so check it out.
Sake is usually pasteurized twice before being marketed (before and after bottling). Nama-zake is not pasteurized.
There are three factors that damage sake: temperature, light, and oxygen
High temperatures, light, and oxygen all deteriorate sake quality.
Make sure you can enjoy your sake by following these three practices for maintaining its quality.
*This is a general guide and may not apply to all types of sake.
Temperature changes aroma
- When in doubt, store sake in a cool place!
- Temperature management is key to preserving sakeʼs delicate aromas. It is best to follow the manufacturerʼs recommended temperature, but it is also okay to store in a cool place like a wine cellar: 5-15℃/40-60℉.
- Keep nama-zake / sparkling sake & ginjo-shu at 4℃/40℉ or lower
- As these styles of sake are particularly sensitive, they need to be stored at much lower temperatures:4°C/40°F or lower.
Types that are refrigerated
(4℃/40℉ or lower)
| Nama-zake | Non-pasteurized sake* that offers a fresher flavor profile. |
|---|---|
| Sparkling sake | Sake containing carbon dioxide gas. Some types called sparkling cloudy sake still contain yeast. |
| Ginjo-shu | The category known for its delicate fruity aroma. Includes junmai ginjo-shu, junmai daiginjo-shu, ginjo-shu, and daiginjo-shu grades. |
* Sake is normally setrilized by heating twice before shipping to stabilize it and make it suitable for long storage.
Types stored in a cool place
(5℃-15℃/40℉-60℉)
| Junmai-shu | Rich rice-derived flavor profile. |
|---|---|
| Long aged sake | Sake aged intentionally before shipping. Sometimes labelled as koshu. Displays a unique flavor profile including aromas reminiscent of caramel, nuts, spice. |
| Misc. | Honjozo-shu and standard sake offer different flavor profiles from the above. |
Light causes a deteriorated smell
- Store sake away from light
-
Contact with light can damage sake’s taste, aroma, and color. As with wine and beer, avoid storing and displaying sake near light sources.
Use non-UV LED lights and UV-cut film. If UV light cannot be avoided, wrap the bottle in paper to protect it.
- Glass bottles that protect sake from light
-
Perhaps you have wondered why sake, wine, and beer are often sold in brown color or dark color bottles. While not so aesthetically pleasing, this color is used to stop light from passing through the glass and changing the quality of the contents.
The graph on the right shows the correlation between bottle color and light transmission. High transmission in the UV region of 400nm or less damages the sake. We can also see that brown and green bottles let less light pass through than other colors.
UV rays are a constituent of not only sunlight but also fluorescent light.
Transmitted light spectrum
of colored bottles
Oxygen accelerates color change
- Seal tightly after opening
- While sake has a higher resistance to oxygen than wine, it is not impervious. Always ensure a tight seal after opening and consume within 1 month. Always store sake upright.
Off flavors?
Mature aromas?
Long-aged sake is sake that is properly stored for 10 to 20 years and is said to have mature aromas. On the other hand, sake that is not preserved properly for an extended period of time deteriorates and produces burnt and sulfur smells that are called hine-ka, or off flavors. Mature aromas and off flavors are distinguishable by their smell alone, but a scientific analysis shows that off flavors have a concentrated presence of dimethyl trisulfide, which smells like cooked onions. Conversely, mature aromas have a high amount of compounds like sotolon and aldehyde that yield smells reminiscent of caramel.
- 110_Ginjyo-ka
- 120_Fruity
- 130_Estery
- 140_Alcoholic
- 150_Floral
- 210_Japanese cedar
- 220_Grassy
- 230_Aldehydic
- 240_Nutty
- 250_Spicy
- 310_Grainy
- 320_Rice bran
- 330_Koji (Fungus)
- 410_Sweet Aloma
- 420_Caramel
- 430_Burnt
- 510_Hine-ka
- 520_Nama_hine-ka
- 530_Light struc
- 610_Yeasty
- 620_Sulfidic
- 710_Rubbery
- 720_Musty
- 730_Papery/Dusty/Earthy
- 740_Plastic
- 810_Diacetyl
- 820_Fatty acid
- 830_Rancid / Acetic
- 910_Sour
- 1010_Sweet
- 1110_Salty
- 1210_Umami
- 1310_Bitter
- 1410_Astringent
- 1420_Pungent
- 1430_Smoothness
- 1440_Mouth coating
- 1450_Afterfeel
- 1460_Carbonation
- 1470_Metalic
- 1510_Amakara (Dryness)
- 1610_Body
420Caramel
Sotolon, 4,5-dimethyl-3-hydroxy-2(5H)-furanone, HDMF CAS 28664-35-9, MW 128.13, bp=184°C at 760mm
- Threshold
- 2.3μg/L
- Concentration in sake
- 0 – 140μg/L
- Associated terms
- 421Honey, 422Dry fruits, 423Molasses, 424Soy sauce
- Importance
- Major flavor impact character of aged sake.
- Origins
- Formed by maillard reaction and/or condensation reaction between α-ketobutyric acid and acetaldehyde.
- Analysis
- Gas chromatography
510Hine-ka
- Standard
- Store sake for 4 weeks at 45°C
- Associated terms
- Importance
- Off-flavor in pasteurized sakes stored under high temperature or oxidative conditions during storage or distribution.
- Origins
- Formed by degradation of amino acids or their related metabolites. Important flavor components are isovaleraldehyde (232) and dimethyl trisulfide (624).
Resources
You can check the detailed information of the introduced contents from the link below.