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How to Degas Coffee Beans?

If you roast your coffee beans at home, you’ll need to understand the degassing concept. Freshly roasted coffee beans are the best for a flavorful cup of coffee. However, brewing a cup of coffee straight after roasting coffee beans will result in a disappointing brew. This is a result of the carbon dioxide gas in your coffee. This article will discuss what coffee degassing is, how to degas coffee beans, the benefits of degassing coffee beans, and how to store coffee beans. Let’s begin.


coffee beans


What is Coffee Degassing?

Degassing is the process of allowing your coffee beans to rest so that the carbon dioxide and other gases that formed during the roasting process are released into the air rather than your cup of coffee. During the roasting process, several gases are formed inside the coffee beans and the majority of the gas is carbon dioxide. Carbon dioxide makes up 90% of the gases formed while the other 10% is nitrogen, volatile compounds, and other gases.

If you brew coffee full of carbon dioxide, the hot water expels the gas from the coffee beans quickly, which interferes with the extraction process resulting in an under-extracted cup of coffee. Usually, coffee flavor is a result of the extraction process which occurs when hot water and the coffee grounds come into contact. Therefore, if there are carbon dioxide bubbles that prevent the water and grounds from contacting, then the coffee extraction process is poor and the flavor is weak.

The coffee degassing process starts immediately after completing the roasting process and will last for two to three weeks. You shouldn’t brew coffee immediately after roasting since that’s when most of the carbon dioxide is escaping the coffee. However, the degassing process requires balancing. You don’t want to degas your coffee beans for too long since the presence of carbon dioxide in the beans is still an indicator of fresh coffee beans. Degas your coffee beans sufficiently.


How to Degas Coffee Beans?

Degassing coffee beans is an easy task for everyone. Most store-bought coffee beans are packaged in a one-way valve bag, that allows carbon dioxide to escape without letting in oxygen. Therefore, you can leave the store-bought coffee beans in the bag. However, if you roast your coffee beans at home, you’ll need a coffee degassing container that allows the carbon dioxide gas to escape while blocking out light, moisture, and oxygen.

The amount of time you’ll need to degas coffee beans depends on the brewing method you’ll use, the processing method, and the type of roast. For the brewing method, the shorter the extraction time of your brewing method, the longer you’ll need to degas the coffee beans. For example, degassing espresso takes longer to get the best extraction. The espresso extraction time is short, so the water and grounds are in contact for a short time. You ideally want to leave your espresso beans resting for seven to 12 days after roasting. Within these days, the beans have fully degassed and carbon dioxide won’t interfere with the extraction process. So you can brew yourself a flavorful cup of coffee. For AeroPress, pour over or drip coffee you can degas your coffee beans for two to seven days. On the other hand, for a French press, you can degas your coffee beans for two days. Usually, immersion or drip methods require a couple of days for degassing since the coffee grounds and water have more contact time.

When it comes to the processing method, natural coffee will take longer to degas than washed coffee. This is because, for natural coffee, the seed has stayed longer in the cherry so you need to wait for approximately two weeks for sufficient degassing. Alternatively, washed coffee degassing takes place within seven or eight days after roasting.

For the type of roasts, light roasts will take longer for the coffee beans to degas compared to dark roasts. This is because dark roasts have degraded more so there are more tiny cracks on the bean allowing carbon dioxide to be released. With a light roast, the bean is intact so it will take longer to release carbon dioxide. Additionally, ground coffee degases more quickly and goes stale quickly too. Therefore, you don’t want to store ground coffee for so long.

For new roasts or new coffee beans, you can get the correct degassing time by brewing a cup of coffee every day until you get your best. As you do this, always ensure you record how many days from the roasting date you are. With this information, you know the ideal degassing time for the new roast.


Why You Need to Degas Coffee Beans?

It is important to degas coffee beans since the carbon dioxide in freshly roasted coffee beans will release immediately after it comes into contact with hot water. Carbon dioxide in your coffee is the reason why you see bubbles in your coffee. The bubbles are a result of carbon dioxide escaping from your ground coffee. Failure to degas your coffee results in under-extracted and sour tasting coffee since the gas bubbles inhibit the proper extraction of coffee.

While carbon dioxide helps form the crema in your espresso coffee, too much of it will prevent proper extraction resulting in a flat-tasting acidic cup of coffee. It is more noticeable with espresso since the brewing process is short and therefore the contact between water and coffee grounds is short too. To have the most flavorful espresso shot, you have to wait for the coffee beans to degas for 7 to 12 days after roasting.


How Do You Know if Your Coffee Beans Have Been Degassed?

There are a few tests that you can carry out to know if your coffee beans have been degassed. The first one is to put some of the degassed coffee beans in a plastic bag that is resealable. Then remove the air in the bag and leave the beans in the bag for a night. If the plastic bag puffs up, the beans are still degassing.

For dark roasts, you can tell whether they have degassed through observation. Dark roasted coffee beans that aren’t fully degassed should look oily and they should leave a residue on your hands after handling them.


Should You Grind Coffee Immediately After Roasting?

Grinding your coffee beans after roasting may help speed up the degassing process. However, you’ll risk your coffee going stale prematurely. This is because coffee grounds have a shorter shelf life compared to whole beans. For the best results, it’s better to degas the coffee beans whole, then grind them when you’re ready to brew them.


Storage for Degassing

How you store your coffee beans during the degassing process is important. Most coffee beans you buy at the stores are packaged in bags that have a one-way degassing valve that lets out carbon dioxide without allowing in oxygen. If you roast your coffee beans, you can find a container or bag with a degassing valve to store them. However, if you can’t find one, you can use an airtight container but ensure you don’t seal the container completely for at least 24 hours. Open the container the next day to let out carbon dioxide and keep the process brief to ensure you don’t let in oxygen, light, and moisture. Air, light, and moisture contribute to staling of coffee.