Does Mirin Go Bad?

In this brief article, we will answer the question “does mirin go bad?” and will guide you about the uses of Mirin, its longevity, and how to ensure that it is safely stored and fit for consumption

Does Mirin Go Bad?

It is unlikely that mirin goes bad, but on rare occasions, it can go bad, especially when contaminated (1). Due to the acidic characteristic of mirin (Japanese rice wine) and its alcohol content, an unfavorable environment is created for the development of microorganisms.

However, studies report that bacteria were found in samples of commercial Japanese rice wine, including pathogenic bacteria, such as E.coli and spores from Bacillus cereus (1).  

How Long Does Mirin Last?

Mirin can last for years at room temperature, when it is produced without the addition of sugars (2). 

In fact, there are two types of mirin: the seasoning mirin is added by sugar and not ripen and is sold after the production to be used in culinary purposes and the ripen mirin, which is not added with sugars, rather is stored for several years to mature. 

Mirin is a fermented sweetened rice beverage. Fermented alcoholic beverages are generally recognized as microbiologically safe due to their high ethanol content (4%) and low pH (<4.5). 

However, these fermented alcoholic beverages are not totally safe from microbial deterioration, mainly because (1):

  • (i) the raw materials are a source of sugars and starches and other important nutrients for the development of bacteria; 
  • (ii) it is possible to occur contamination during the manufacturing processes 
  • (iii) the fermentation temperature (generally 18 to 35°C for 2 to 14 days) is favorable for bacterial growth (both for the starter cultures and for spoilage and pathogenic bacteria).

A sealed bottle of Mirin – stored properly in a cool, dark place safe from moisture – can last for months and even years. Usually, mirins used for special cuisines are fermented for several years to develop flavor. 

A study compared for up to 13 years ripen mirin with non-ripen mirins and showed that the percentage of specific amino acids in mirins matured for seven years or more was higher than in non-ripened mirins (2). 

Should Mirin Be Refrigerated After Opening?

It is recommended that Mirin be refrigerated after opening to preserve its quality and flavor for longer and enhance its shelf life.

In general, as long as Mirin is kept in a cool, dark place protected from sunlight and moisture, it can be adequately stored out of the refrigerator. However, a study detected bacterial growth and physicochemical changes in Korean rice wine stored at 20°C after 3 days. 

No significant changes were detected in the rice wine stored at 4°C (fridge temperature) after 30 days. Therefore, it is recommended to store opened bottles of mirin in the refrigerator (3).

What Should Be The Color and Consistency of Good Mirin?

Ideally, Mirin is lightly golden and amber in color with a slightly thick and syrupy consistency. This confirms that the sauce is preserved well.

Changes in color and increase in turbidity indicate changes in the bioactive compounds present in the wine-type beverages. Loss on phenolic compounds, tannins and antioxidant activity and pH changes occur during long storage (4).  

How Do You Know If Mirin Has Gone Bad?

There are three main things to watch for when checking if Mirin has gone bad: color changes, pungent or different smell, or an off-taste. Bottle bloating indicates gas formation due to microbial activity (1).

The action of bacteria derived from the product contamination results in changes such as the generation of sour flavor, bad odors, and turbidity. Bacteria produce lactic acid, diacetyl and acetoin which changes the flavor and appearance of the mirin. 

Acetic acid bacteria contamination can produce a vinegar-like sourness, bitterness, acetic smell, or a nutty or solvent smell (1).

What happens if you consume spoiled mirin?

By consuming spoiled mirin, it is possible that you experience an episode of foodborne illness. As mentioned earlier in this article, mirin is susceptible to be contaminated by pathogenic bacteria (1).

When pathogenic bacteria or their toxins are ingested, they are able to cause harmful effects, such as diarrhea, vomiting, fever, as a consequence of food poisoning.

Although individuals who are very young, elderly, or have weakened immune systems are particularly vulnerable to severe consequences from most foodborne illnesses, certain microorganisms listed below can pose significant dangers to people of all ages and health conditions (5). 


In this brief article, we answered the question “does mirin go bad?” and told you about the uses of Mirin, its longevity, and how to ensure that it is safely stored and fit for consumption. 


  1. Jeon, Se Hui, et al. Microbiological diversity and prevalence of spoilage and pathogenic bacteria in commercial fermented alcoholic beverages (beer, fruit wine, refined rice wine, and yakju). J food protec, 2015, 78, 812-818.
  2. Inoue, Yutaka, et al. Mechanisms of D-amino acid formation during maturation of sweet rice wine (mirin). Food Sci Technol Res, 2016, 22, 679-686. 
  3. Kim, Jae Young, et al. Effects of storage temperature and time on the biogenic amine content and microflora in Korean turbid rice wine, Makgeolli. Food Chem, 2011, 128, 87-92.  
  4. Sant’Anna, Voltaire, et al. Tracking bioactive compounds with colour changes in foods–A review. Dyes Pigments, 2013, 98, 601-608.
  5. What you need to know about foodborne illnesses. US Food and Drug Administration. 

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