Why Does Coffee Taste Stale?

We all love sipping on a fresh cup of coffee; some may say it soothes our souls. But there are those times when you’re faced with the unwanted flavors of a stale-tasting cup of coffee. What makes your coffee taste stale?

Stale coffee is the result of oxidation, a chemical reaction that changes the coffee beans/grounds’ compounds due to oxygen exposure. Heat and sunlight can increase the rate at which this occurs. As coffee oxidizes, the flavor is affected negatively and tastes stale. 

Unfortunately, coffee beans or grounds don’t last forever. Although you can technically store them in your cupboard for years without fear of making you ill from drinking it, the coffee’s taste will not be fresh but instead, have a stale taste.

What is Oxidation?

Oxidation is a scientific term used to describe a chemical reaction that occurs as a substance comes in contact with oxygen. In our discussion today, we are looking at when coffee beans come in contact with oxygen, a chemical reaction occurs, thus making the coffee beans stale.

This is only one example, but oxidation can occur with many other substances. For instance, another example of oxidation is when iron reacts with water and oxygen, it creates rust.

After coffee beans are roasted, oxidation promptly kicks in. As the beans are exposed to oxygen, their taste begins to alter. Although you can’t eliminate the effects of oxidation on your coffee beans, there are some ways to help slow the process that we’ll discuss in a bit.

Ways to Keep Coffee Beans Fresh Longer?

No one enjoys stale coffee, so what are some ways you can prolong that freshness for longer? Fortunately, there are some tips and tricks to keep your morning cup of Joe tasty and without that noticeable staleness.

Table explaining how to prevent stale coffee. 
Buy whole beans instead of ground coffee.
Only buy what you need. 
Purchase directly from a Master Roaster. 
Grind beans as needed. 
Store beans in an air-tight container.
Store in a dry dark place.

Let’s dig a little deeper into each of the tips listed above.

Buy Whole Beans vs. Ground Coffee

Buying whole coffee beans is always better for taste than using ground coffee. Even though buying your coffee pre-ground is highly convenient and a time-saver in the morning, it’s not the best option.

Once coffee beans are ground, there’s more area being exposed to the air. You go from having a few hundred beans in a bag to a few thousand ground particles, so air can reach more coffee and degrade it quicker.

Just like cutting up a child’s hot food to get air to it faster so it cools quicker, grinding up the coffee beans gets more air to them faster. This means if you can buy freshly roasted coffee and grind it each time you want to use it, you will have a much fresher and tastier brew to drink.

Only Buy What You Need

This tip is pretty straightforward; only buy what you need. This is especially for you if you like to stock up on items to prevent going to the store every week.

The longer coffee sits on your shelves, the staler they are growing. If you don’t want to go to the store weekly, I recommend buying your beans from an online coffee shop.

Here at Taste the Latte, we can ship freshly roasted coffee beans of your preferred flavor right to your door.

Purchase Directly From a Master Roaster

Master Roaster is a highly experienced coffee professional responsible for taking green coffee beans grown in various places and seasons and implementing roasting techniques to produce specific roast and flavor profiles.

When bypassing store-bought coffee and going directly to the coffee roaster, you’ll be getting higher quality beans that have recently been roasted rather than sitting in a warehouse or store shelf for longer.

All our coffee at Taste the Latte is air-roasted by our Master Roaster daily. To learn more about how we roast our coffee and to see the flavors we offer, click here!

Grind Beans as Needed

Similarly, just how it is best to purchase whole beans over ground; it is optimal to wait to grind your beans before each use. Again, beans have less surface area than ground coffee; therefore, less oxygen is able to penetrate it.

Store Beans in an Air-Tight Container

You want to limit the amount of oxygen that reaches your coffee beans as much as possible. Once opened, be sure to reseal the bag properly if it has the ability to do so. If unable to reseal the bag, transfer all the coffee into an airtight container.

Canisters explicitly designed for coffee are great. Below are some of the ones I have used and recommend.

Store in a Dry, Dark Place

If you’ve bought a bag of coffee, it’s very likely the beans will be in an airtight bag. Before you open it, store it in a dark, dry place like a cupboard. As we’ll discuss later, light and moisture are other components that will affect the freshness of your coffee beans.

This is another reason why I highly suggest using a Coffee Gator listed above for storage. The canister is not see-through, eliminating sunlight’s chance to affect your coffee.

Besides Oxygen, What Else Affects How Long Coffee Stays Fresh?

The most significant effect on the freshness of your coffee beans is oxygen, but exposure to light and moisture also plays a role.

Primarily sunlight, but also house lights, make coffee lose its freshness quicker. As staleness increases, that delicious smell will become less pungent, and the flavors will become less intense. In addition, less favorable flavors start to develop. Once this happens, you will have stale coffee beans. Using stale beans will produce a flat, woody, and papery taste.

And for those lovers of dark roast coffees, unfortunately, they tend to go stale quicker than lighter roast coffee. This is because it’s more permeable so that air can get to it more easily.

How to Tell if Your Coffee Beans Have Gone Bad?

Now that you’ve done everything right to keep your coffee beans fresh for as long as possible, you may be wondering how to tell when they start to go stale. We have three tricks to help you make that determination.

  • Check the expiration date
  • Try the plastic zippy bag test
  • Smell them

The first and last tips seem reasonable, but the second may have you questioning. If so, check out our other article to learn exactly what this plastic zippy bag test is about.

How Long Do Coffee Beans Typically Last?

How long is the coffee bean lifespan on average anyway? Even if you follow all the tips described previously, coffee beans aren’t going to last forever. Typically, if your coffee beans are unopened and stored in a vacuum-sealed container or bag, then the beans will keep for six to nine months. 

Once you open them, your coffee beans are good for about six months. Keep in mind, though, that the longer they sit, the more they are oxidized; thus, the staler they are growing. So, even if they are edible, the faster they are used, the fresher your coffee will taste.

Final Thoughts

No one appreciates stale coffee, so limiting the amount of oxygen, light, and moisture getting to your coffee beans is essential. Hopefully, after reading this article, you’ve learned how to prevent coffee staleness for longer and get a fresh-tasting cup of coffee every time.

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