Does rice vinegar go bad?

In this brief guide, we will address the question, “does rice vinegar go bad” as well as other related questions pertaining to the subject at hand like how much time does rice vinegar take to go bad or does its acidity changes over time and what are some of the storage practices needed to prolong the shelf life of rice vinegar.

Does Rice vinegar go bad?

Rice vinegar that is commercially available generally does not expire, unless it has been contaminated. It retains the best quality for a minimum of 2 years and remains safe for consumption even past this time. After this time, its flavor may start to suffer since the mentioned date is for best quality only.

Vinegar is produced through the acetous fermentation of dilute alcoholic solutions, it can also be made through microbiological processes using natural alcoholic solutions or by diluting acetic acid.(1)

Rice vinegar is the aged and filtered product obtained from the acetous fermentation of sugars derived from rice. It is excellent for flavoring with herbs, spices and fruits due to its mild flavor. (2)

This vinegar has a fairly low acidity and a high amino acid content. It is light in color and has a clean, delicate flavor.It is therefore highly prized in oriental cooking since it does not significantly alter the taste of the food (1)

Rice vinegar has acidity of approximately 5% and pH between 3.6 to 4.0. Making it unfavorable for more bacteria to grow because of the competition that takes place inside the medium. Difference in acidity and pH of rice vinegar according to types of yeast is not significant. (3)

Commercially prepared rice vinegars are safe indefinitely. However, over time, the appearance and flavor of non-white vinegars may start to change.  Most of these changes are harmless if the vinegar has been stored properly with its best quality if used within 2-3 years of purchase.(4)

What are the health implications of consuming contaminated vinegar?

Spoiled vinegar may contain toxins that can result in harm to essential organs and systems like the liver, kidneys, and immune system. Additionally, it can adversely impact the gastrointestinal system by disrupting the intestinal barrier function and the balance of intestinal microbiota. (5)

The most used fermentation method employed to produce traditional rice vinegar, has some disadvantages such as a long fermentation period, a risk of contamination and difficulty of quality control.(7)

What changes may occur over time?

Some methods of fermentation can lead to the formation of a pellicle-like film on the surface. Formation of such a film causes overoxidation and turbidity in vinegar.(7)

Like other kinds of vinegar, rice vinegar does not expire, but some organoleptic or aesthetic changes might occur over the course of time that may be the result of exposure to light and air, these changes are mainly due to improper storage: (1-4)

Like red wine vinegar, rice vinegar may get hazy or cloudy due to deposition of some sediments, but they can be removed after filtration and vinegar are good to use again. Rice vinegar will become darker and thicker the longer it is kept in storage.

It can develop a slimy substance particularly known as ‘mother’ because it can be used to make a new batch of vinegar. 

Similar to other food products, vinegars undergo oxidation once they are opened. Oxidation leads to various chemical and enzymatic reactions that modify the vinegar’s composition, resulting in a decline in quality. Thus, the main cause of vinegar quality deterioration is the presence of oxygen.

How to store rice vinegar?

Rice vinegar can be stored in a cool and dark cupboard. It should be kept away from heat or sunlight. The bottle of rice vinegar should be kept tightly sealed after opening.

How to expand rice vinegar  shelf life?

Storing rice vinegar is pretty similar to storing other kinds of vinegar, like balsamic or red wine. 

Proper storage helps in reducing food waste and maximizing food quality by delaying their deterioration and decomposition processes. Rice vinegar should be stored in an airtight properly sealed container to protect it from oxidative changes.(4, 6)

 If exposed to air, it will suffer  evaporation resulting in loss of flavor. It should be placed at the dry place at room temperature. (6)

Direct sunlight and heat could degrade the vinegar much more quickly. Rice vinegar should be kept away from heat sources and light at some dark place to extend its shelf life, with some brands recommending ambient storage and others in the fridge.(4)

Other FAQs about Vinegar which you may be interested in.

Does vinegar expire?

How long does Balsamic vinegar last?

Conclusion

In this brief guide, we have addressed the question, “does rice vinegar go bad” as well as other related questions pertaining to the subject at hand like how much time does rice vinegar take to go bad or does its acidity changes over time and what are some of the storage practices needed to prolong the shelf life of rice vinegar.

References

  1. M. Plessi, VINEGAR, Encyclopedia of Food Sciences and Nutrition (Second Edition), Academic Press, 2003, 5996-6004,
  2. Chin Wai Ho, et al, Varieties, production, composition and health benefits of vinegars: A review, Food Chemistry, 221, 2017,
  3. Lee S-W, Kwon J-H, Yoon S-R, Woo S-M, Jang S-Y, Yeo S-H, et al. Quality Characteristics of Brown Rice Vinegar by Different Yeasts and Fermentation Condition. Journal of the Korean Society of Food Science and Nutrition. 39, 1366–72 2010.
  4. Marlene Geiger, Vinegar Shelf Life and Safety, Iowa State University, Answer Line, 2021
  5. Z.D. Heperkan et al, Unexpectedly high patulin contamination and co-occurrence of ochratoxin A in homemade vinegar, Food Control 148, 2023.
  6. Minjeong Kang, Jung-Heun Ha, Youngseung Lee, Physicochemical properties, antioxidant activities and sensory characteristics of commercial gape vinegars during long-term storage, Food Sci. Technol, Campinas, 40(4): 909-916, 2020.
  7. J. H. Yun et al, Surface Film Formation in Static-Fermented Rice Vinegar: A Case Study, Mycobiology, 47, 2, 250–255, 2019