Coffee Bloom

Everything you need to know about Coffee Bloom

If you’re an avid coffee lover or even a casual drinker of this particular beverage, you must have heard about the term ‘Coffee Bloom’’. This term is frequently used in the coffee-shops or amongst the coffee-aficionados. If you’re a newbie, you might have a few questions in mind regarding this particular term including,

What is the meaning of Coffee Bloom?

Why should you bloom Coffee?

And how to bloom Coffee?

If you’re looking to the answer of the aforesaid questions, you’ve just landed at the right place. We’ve prepared this guide, to clear up all things related to coffee bloom.

What exactly is a Coffee Bloom?

Brewed Coffee

Coffee bloom is the rapid release of CO2 gas that occurs when hot, boiling water comes in contact with coffee grounds.

During the process of roasting, in which coffee beans are subjected to extreme temperatures, CO2 gas gets trapped inside these coffee beans. Once the process of roasting is complete, coffee beans start to emit CO2 gas at a slow rate. This process is known as degassing.


If you use coffee beans within ten days of the roasting process, they will still have a decent amount of carbon dioxide trapped inside regardless of the continuous degassing process. When you grind such beans, they start emitting CO2 gas at a much rapid rate than that of degassing.

Once hot water touches freshly ground coffee, it will cause the beans to purge themselves of the remaining CO2 which eventually creates a blooming effect. The more the gas that is leaving the beans, the bigger the booming effect which you will observe.

bloom Coffee


Coffee bloom is an important factor to determine the quality of beans. When the normal loss of gases begin as soon as the process of roasting is complete, it will take no less than 2 or more weeks for all the gases to leave coffee beans.

These gases are a key reason of why coffee is such a flavorful beverage so you would want them to remain inside the beans for a considerable amount of time. And that’s why veteran coffee lovers insist on grinding the coffee beans just before brewing.


It will inform you about the freshness of beans. As already described, freshly grind beans will still contain some amount of CO2 which is a vital ingredient to keep oxygen at bay.

Otherwise, oxygen will start the process of oxidation inside the coffee beans which will eventually result in a stale coffee. So, you would want to remove CO2 just before brewing and it will produce a tastier cup of Java.

Why should you Bloom Coffee?

It is important to bloom/degas coffee for removing some acids from the freshly ground coffee beans. Even though it might remove some of the tastier acids including malic/citric acid, it’s none other than carbon dioxide gas which is released sooner in the process of blooming.

Else, CO2 gas will get trapped inside the beans before reacting with water to form carbonic acid. Carbonic acid will give a sour taste and unlike coffee’s original flavor, this isn’t a very good sour taste.


Factors Affecting Bloom

bloom Coffee

Starting from temperature, following are the key variables which normally affect the process of blooming.

  • Temperature: One should always select a cooler environment for storing his or her coffee beans. If you choose a hotter area for the storage of coffee beans, it will trigger the gases to escape at an enhanced rate. Once you use such type of beans, they will have already lost all the flavor even before the process of brewing. So for the sake of freshness, you would want to store the coffee beans away from your kitchen or any other such place.
  • Humidity: The dryer the place, the greater the gases which will escape from your coffee beans. But on the other side, choosing an area with high humidity levels will make them vulnerable to all kinds of bacterial activities. So while looking for a suitable place, choose one which possesses a medium level of humidity.
  • Level of Roasting: Depending on the type of roasting, some beans will exhibit a greater level of bloom as compared to others. For example, darker roasts, which have undergone a longer session of roasting, will bloom more as compared to lighter roasts.
  • Bean Hardness: A bean with a considerable amount of hardness will make it much difficult for the CO2 to escape. On the contrary, there will be no such problem for different gases to escape through a relatively softer bean.


How to Bloom

bloom Coffee

Depending on the type of coffee maker you own, there are a number of ways to perform the process of blooming.

For the owners of Pour overs, they just have to start pouring hot water on the coffee grounds. Start from the outside before making your way into the middle. Always use a very small quantity of water for this purpose as you just have to soak the coffee. Afterward, allow it to remain as such for a minute or two before making Pour Over Coffee.

If you own a French Press, pour boiling hot water directly over the freshly ground coffee. Wait for 20 seconds and then start stirring with the help of spoon. Once you do that, now you can carry on with your normal brewing routine.

As per Automatic Coffee Makers,

Take out a filter and place it inside the coffee-maker’s basket. Add ground coffee to it before soaking it with a small amount of water. Afterward, allow the process of blooming to complete for about 90 seconds and now you’re good to go with your normal regime.


Now you fully understand the concept of blooming, you can explain it to your friends who’re still fawning over a bloom. And yes, do you know what is a FLAT White Coffee?

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