How Long Do Coffee Grounds Last?

For many coffee enthusiasts who brew at home, a coffee grinder is not a necessity, so they often opt for the grinding services provided by businesses. However, once coffee beans are ground into powder, the rate of flavor loss significantly accelerates, leading to a reduction in their flavor lifespan. So, the question arises: How long can ground coffee be stored after grinding? Let's delve into the factors that affect the lifespan of coffee powder and how to make the most of them.

How long can ground coffee stay fresh?

Compared to whole coffee beans, ground coffee tend to lose their freshness a bit faster—generally, if properly stored, the former may start to lose coffee flavor after 1-2 weeks, while the latter may last up to a month. But why does the flavor lifespan more than halve after grinding?

Why does the loss speed increase?

It's simple—the culprit is a compound we often mention: "carbon dioxide." Coffee beans contain a significant amount of carbon dioxide after roasting! The presence of carbon dioxide not only hinders the extraction of flavor compounds by hot water but also slows down the loss of flavor compounds.

When the coffee beans are still intact, the non-porous structure slows down the release of carbon dioxide. However, when we grind the coffee beans into powder, the formerly "trapped" carbon dioxide is released due to the breaking of the bean's surface, and with the significantly increased surface area exposed to air, the rate of carbon dioxide loss speeds up. As a result, when the carbon dioxide, which impedes the loss of flavor compounds, decreases, the loss rate of flavor compounds also accelerates.

If you've ever ground your own coffee beans and noticed a significantly stronger aroma after grinding, you've experienced this oxygen exposure in real-time. So, what we need to do is to minimize the loss of aroma compounds as much as possible.

Additionally, humidity and temperature also affect the shelf life of ground coffee.

How to properly store ground coffee to preserve flavor as much as possible?

1. Sealing of the packaging

Generally, sealing the bag of ground coffee (especially at the exhaust valve) can reduce oxygen infiltration and extend the flavor lifespan. However, once we open the bag of ground coffee, this sealing effect weakens, allowing air to enter the bag through other pathways. Therefore, you can purchase vacuum-sealed containers to reduce the loss of flavor compounds by extracting air.

2. Reduce the frequency and duration of opening containers

Every time we brew coffee, we need to open the bag or container of ground coffee and take out the desired amount of coffee powder. This action exposes the other ground coffee in the bag to a significant amount of fresh oxygen, leading to the loss of flavor compounds. The more frequent the openings and the longer they last, the more flavor compounds are lost. 

Therefore, it's best to minimize the number of times the container is opened and the duration it stays open! Seal the bag immediately after measuring the coffee powder to reduce its exposure to air and preserve the flavor compounds. Alternatively, you can divide the ground coffee into multiple containers and use them separately.

3. Storage environment

As mentioned earlier, whether it's coffee beans or ground coffee, it's best to store them in a cool, dry place. They are most sensitive to high temperatures and humidity! High temperatures accelerate the evaporation of coffee aroma, while humidity makes ground coffee prone to moisture absorption, resulting in off-flavors. Therefore, storing coffee beans/ground coffee in a cool, dry room temperature environment is most suitable for preserving the aroma of coffee powder.

Some coffee enthusiasts believe that freezing ground coffee can preserve their flavor for a long time. However, be cautious, as the temperature difference when taken out of the refrigerator can cause water vapor in the air to condense, making the ground coffee susceptible to moisture, which may affect the flavor.

Repurposing

If you find that your ground coffee have been sitting for more than two weeks and have lost some flavor, they can still be used for various purposes, such as composting, exfoliating skincare products, or neutralizing odors.

Conclusion

In conclusion, the lifespan of ground coffee depends on how they are stored and how quickly they are used. While ground coffee only stays fresh for a short 1-2 weeks, by following proper storage techniques and being creative with their use, you can make the most out of your ground coffee and enjoy their flavor for as long as possible. Remember that even if the flavor diminishes over time, ground coffee can still serve a multitude of purposes beyond brewing a cup of coffee. So, don't be too quick to discard them!

Works Cited

“How to store coffee grounds and why they shouldn't be in the refrigerator”,

https://www.homesandgardens.com/advice/how-to-store-coffee-grounds