Can coffee beans go bad?

In this brief guide, we will discuss the following question, “can coffee beans go bad?”  and other queries related to this topic.

Can coffee beans go bad? 

Yes, coffee beans can go bad at some point. After the roasting process, coffee beans begin to lose their flavors, gradually diminishing their quality characteristics. 

This deterioration occurs due to the simultaneous occurrence of oxidative reactions and flavor depletion, commonly known as coffee staling. The presence of lipid oxidation during storage further exacerbates this process, resulting in the formation of unpleasant flavors. 

As a consequence, the product becomes less desirable or completely unacceptable to consumers, indicating the end of its shelf life. (1)

How long do coffee beans last?

Coffee beans can last for about one month, when stored in contact with oxygen and humidity like in cardboard bags which are the oldest type of packaging used to store and sell roasted whole beans. 

Coffee in cardboard bags is in contact with air. This implies a high oxygen level in the bag headspace and thus a short shelf life, estimated to be around 1 month.

The choice of coffee packaging material and technology is fundamental in order to reduce the rate of staling and ensure the longest possible shelf life of roasted coffee products.

Proper packing allows a significant extension of coffee product life, generally longer than 12–18 months. (1)

How to store coffee beans?

To store your coffee beans, make sure to preserve them in an air-tight container or their original packaging if not opened. Also, keep them in a dry, cool place far from heat and direct sunlight. Moreover, it is recommended to place them in an opaque container.

Additionally, make sure to close the cap or the lid of your jar thoroughly after opening because if not closed air and humidity will get inside leading to bacteria and mold development, thus the shelf life will decrease and you will have to throw it away. (1, 2)

How do coffee beans go bad?

When coffee beans undergo lipid oxidation during storage, it leads to the creation of undesirable flavors, resulting in reduced acceptability or complete unacceptability among consumers. This process marks the end of the coffee beans’ shelf life.

In addition to oxidation, changes in the flavor profile can also occur due to the release of volatile compounds. For example, thiols, which are coffee odorants, tend to volatilize, leading to a decrease in the sensory quality of the coffee.

The simultaneous occurrence of oxidative reactions and flavor loss gives rise to what is commonly known as coffee staling. 

This phenomenon is characterized by a sweet yet unpleasant flavor and aroma in roasted coffee, which reflects the oxidation of many pleasant volatile compounds and the loss of others. It also involves a change in the flavor and acid constituents, resulting in a partially bland taste. (1)

What factors affect coffee spoilage?

The rate of coffee staling is primarily influenced by the environmental conditions experienced by the coffee beans after roasting. 

Factors such as storage temperature play a significant role, as higher temperatures can promote both the release of volatile compounds and oxidative reactions. 

Additionally, light exposure and oxygen concentrations in the surrounding space accelerate the oxidative processes. It is also important to consider the presence of water vapor in the environment. 

When the moisture content exceeds the monolayer capacity, water competes for the polar sites within the coffee matrix, disrupting the interactions among carbohydrates that physically retain the volatile compounds. 

As a result, there is a significant loss of volatile compounds, particularly those with polar characteristics. (1)

How to tell if your coffee has gone bad?

Sensory analysis, involving the olfactory evaluation of coffee powders or the tasting of coffee brews, has become a widely utilized method to assess the progression of staling throughout coffee storage. 

It is worth mentioning that microbial growth is not a concern when it comes to whole and ground roasted coffee. 

This is primarily due to the low water activity in coffee, the absence of essential nutrients for microbial growth, and the presence of melanoidins with antimicrobial properties. These factors collectively act as safeguards against microbial spoilage. (1)

What are the risks of consuming spoiled coffee beans?

Properly stored coffee rarely poses a risk of causing foodborne illnesses. This is attributed to the favorable combination of factors that contribute to its microbial stability. 

Coffee’s low water activity, lack of essential nutrients, and the presence of antimicrobial melanoidins collectively prevent the growth of spoilage-causing microorganisms. As a result, even when coffee has exceeded its optimal freshness, the risk of microbial contamination remains minimal. (1,2)

Conclusion

In this brief guide, we discussed the following question, “can coffee beans go bad?” and other queries related to this topic.

References

  1. Manzocco, L., Melchior, S., Calligaris, S., & Nicoli, M. C.  Packaging and the Shelf Life of Coffee. Reference Module in Food Science. 2019.
  2. Adrienne Seitz, Lizzie Streit, How Long Does Coffee Last? Ground, Brewed, Cold Brew, and More, Healthline Media LLC. 2021.

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