What Is Coffee Degassing And Why Does It Matter?

What Is Coffee Degassing?

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Have you ever wondered why freshly roasted coffee beans emit gas when you open the bag? This is due to the degassing process, where carbon dioxide is released from the beans after roasting. But why is degassing important?

In this article, we will explore the science behind coffee degassing and its impact on the flavor and aroma of your coffee. We will also discuss the different methods used to degas coffee and how to properly store freshly roasted coffee beans for maximum freshness.

Whether you are a coffee enthusiast or a coffee professional, understanding coffee degassing is essential for brewing the perfect cup of coffee.

✔ Quick Answer

Coffee degassing is the process where freshly roasted coffee beans release carbon dioxide, a natural byproduct of the roasting process. This release of gas, occurring mostly within the first few days after roasting, affects the flavor and brewing quality of the coffee, which is why it’s often recommended to wait a bit before brewing.

If you want to know more, stick around. Let’s dive into the ins and outs of coffee degassing.

What Is Coffee Degassing?

I’m sure at some point during your coffee journey, you’ve come across the term “coffee degassing?” If you haven’t figured it out, the coffee degas is the natural release of carbon dioxide (CO2) from freshly roasted coffee.

When coffee beans are roasted, a complex chemical reaction occurs, and one of the by-products is CO2.

Once the coffee has been roasted, the clock starts ticking, and the CO2 that remains trapped inside the roasted beans gradually escapes from the beans in a process called ‘degassing’; this process can continue for a few weeks.

If you were to use freshly roasted beans immediately after roasting, the excess CO2 will more than likely cause an undesirable taste in your coffee.

During the first few days after roasting, the coffee beans release CO2 rapidly, making them less suitable for brewing immediately.

In fact, the excess CO2 can be so prominent that when brewing coffee with methods like espresso or Aeropress, the rapid release of gas can obstruct the process and lead to inconsistent results.

So after roasting, it is generally recommended to let the beans rest and release gas for a couple of days before brewing – more on that later.

It’s also important to note that various factors can play a role in the process, such as the coffee bean variety, the roast level, and storage conditions.

For instance, I’ve noticed that darker roasts tend to release CO2 faster compared to lighter ones. Similarly, different bean varieties often vary in their degassing rates.

roasting coffee in a commercial machine

How Does Carbon Dioxide Get In Coffee?

When coffee beans are in the roaster, they undergo a number of chemical reactions; These reactions cause coffee beans to release carbon dioxide in significant amounts.

One of these reactions is the breakdown of complex sugars and the formation of carbon dioxide gas in the coffee beans. This carbon dioxide becomes trapped inside the cell structure of the beans, leading to the gas being released gradually over time.

Once roasted, the degassing process starts, and the carbon dioxide trapped inside the fresh coffee beans starts to escape slowly.

This isn’t bad, as this process is crucial for the coffee’s freshness and overall flavor development.

How long does it take? Coffee degassing takes place within the first 24 hours after roasting and continues over a period of weeks, with the majority of the trapped gas being released within the first few days after roasting. 

It is important to understand that different factors influence the amount of carbon dioxide present in roasted coffee beans. For example, darker roasted beans generally tend to have a higher concentration of CO2 due to more prolonged time in the roaster. 

Finally, it is worth noting that while the degassing process is needed for flavor development and the coffee brewing process, an excessive amount of CO2 can be detrimental. Too much CO2 can lead to acidic flavors in the final brew, while too little can result in a flat taste.

As a coffee enthusiast, it’s your goal to try and find the right balance for the perfect cup of coffee.

How Long Do Coffee Beans Need To Degas?

Understanding the art of degassing coffee beans is fundamental to unlocking the full potential of different types of coffee roasts.

light roast and dark roast time to degas

Below I have highlighted the optimal periods for both light and dark roasts. 

Lighter Roasts

In my experience, lighter roasts require a longer time for degassing, typically around 4-7 days. This is because the beans have been roasted for less time, which means they have had less exposure to heat.

As a result, the internal gas pressure within the beans is usually higher, and it takes longer for the gases to release at a proper rate.

– Lighter roasts: 4-7 days

Darker Roasts

On the other hand, darker roasts may require a shorter period of degassing. For these beans, the process usually takes around 2-5 days.

Due to the longer roasting time, the coffee grounds have had more exposure to heat, expelling gases at a faster pace.

– Darker roasts: 2-5 days

Throughout my coffee brewing journey, patience has always been key when it comes to letting my beans degas. The more time I allowed them to release their excess gas, the better my brews generally tasted.

Resisting the urge to brew my coffee grounds too soon can significantly improve the taste and quality of your final cup.

How Do You Know If Your Beans Still Need Time To Degas?

From my own testing, I have learned that giving the coffee beans proper time to degas after the roasting process is essential to extract the best flavors. Determining when your beans are at their prime degassing time peak coffee freshness can be a little tricky. 

But here’s one simple way to check if your roasted coffee bean still needs time.

Place them into a resealable plastic bag, ensuring no or very little air is trapped in the bag, and then seal it tightly. After that, leave the bag overnight or longer, depending on the beans’ age.

The next day, check the bag to see if it has puffed up.

If the bag puffs up, it indicates that the beans are still releasing carbon dioxide, meaning they require additional time to degas. If the bag doesn’t puff up, it is a good sign that the degassing process has been completed and the beans are ready for brewing.

But be careful not to jump to conclusions based solely on this method.

It’s a good indicator but not foolproof, as the amount of carbon dioxide released depends on factors like the beans’ age and roast level. Nonetheless, it is a good starting point to feel confident about your beans’ readiness for brewing.

Coffee Degassing By Blooming

Once ground, a good technique to degas your coffee is called “blooming.”

Blooming is a process that helps degas coffee beans and improve the overall flavor of the brewed coffee. 

blooming coffee to degas

So how can blooming help with degassing? Coffee bloom is the foaming or bubbling seen when hot water comes into contact with freshly ground coffee.

This reaction occurs as the CO2 trapped inside the coffee grounds escapes as a result of the heat and moisture. By blooming, you’re effectively pre-infusing the coffee, giving the grounds time to release CO2 and ensuring a more even extraction when the rest of the water is added.

To achieve an ideal coffee bloom, follow these simple steps:

  1. Weigh and grind your coffee beans: Accurate measurements are crucial to brewing delicious coffee. Weigh your beans, making sure to use about 60 grams per liter of water, and grind them to a medium-coarse consistency.
  2. Pre-wet your coffee filter: Dampen the coffee filter to prevent it from absorbing the flavorful coffee oils during brewing.
  3. Add the coffee grounds to the filter: Evenly distribute the freshly ground coffee in the dampened filter.
  4. Pour hot water over the grounds: Pour hot water (around 200-205°F) over the coffee grounds, using just enough water to saturate the grounds. Then wait for 30 to 45 seconds for the bloom to occur.
  5. Continue brewing: After the bloom phase, continue to pour hot water over the coffee grounds at a steady pace until the desired amount of brewed coffee is reached.

By incorporating blooming into your brewing routine, you can better ensure that your coffee beans are adequately degassed, translating to a more delicious and balanced cup of coffee.

Proper Storage And Packaging

In my experience with coffee, I have learned that proper storage and packaging are essential to preserving the freshness and flavor of coffee beans.

To ensure the best taste and aroma in your coffee, it is crucial to store the beans in a manner that allows your coffee to degas appropriately.

One effective method to store coffee beans is to use an airtight container. I always opt for a container with a tight seal that prevents air, moisture, and light from penetrating inside but features a one-way degassing valve.

>> Looking for a good coffee storage container?

coffee packaging with one way valve to degas

A one-way valve is a crucial element to have, particularly in coffee packaging. The valve allows carbon dioxide to escape while preventing oxygen from entering. This function ensures that the beans are continuously degassing in a controlled manner, thus retaining their peak flavor.

In addition to the container, the material and design of the coffee packaging contribute to optimal storage conditions.

I typically look for packaging with a one-way valve and resealable feature. High-quality packaging should be opaque, puncture-resistant, and offer a barrier against moisture, oxygen, and ultraviolet light.

Degassing Coffee Conclusion 

So there you have it! As you can see, coffee degassing is a crucial process affecting your coffee’s flavor and aroma. Remember, patience is essential, and make sure to allow lighter roasts 4-7 days and darker roasts 2-5 days to degas.

Also, don’t overlook blooming your coffee at home. Blooming during brewing helps release excess CO2 as well as helps to enhance the flavor of the freshly brewed coffee.

And when storing your coffee, always use proper storage with an airtight container and a one-way valve to preserve freshness. 

Whether you’re a coffee enthusiast or a coffee professional, understanding coffee degassing and its impact on your daily cup is a valuable piece of knowledge.

By appreciating this natural process and implementing proper brewing and storage techniques, you can unlock the full potential of your favorite coffee beans and elevate your coffee experience to a whole new level.

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