Discover What is Coffee Bloom: The Key to Coffee Excellence

what is coffee bloom

If you brew your coffee at home, you’ve probably noticed that sometimes your coffee just isn’t reaching its full potential. Maybe it’s not as rich and robust as you expected, or maybe your coffee isn’t as good as your local cafe’s. It could have to do with a process called blooming.

It’s likely that, as a coffee enthusiast, you’ve heard the term before. But so many of us still don’t really know what coffee blooming is or how it can turn your home-brewed regular cup of joe into a cup of delicious magic. 

Coffee blooming refers to the chemical process that allows carbon dioxide to escape when coffee is brewed. The CO2 that escapes during the process negatively impacts the flavor of coffee. When coffee blooms, the process allows water to fully extract any potential flavors from the coffee grounds.

Key Takeaways:

  • Understand what coffee blooming is and how it affects your home-brewed coffee.
  • Learn the proper technique of coffee blooming to help your home-brew reach its full potential.
  • Discover the dos and don’ts of coffee blooming.
  • Explore the impacts that water, beans, and brewing methods have on the blooming process.

Discover what coffee blooming is, its importance in brewing, and how to achieve the perfect bloom for a richer, more flavorful cup of coffee.

The Science Behind Coffee Bloom: Explore Roasting, Freshness, and Gases

Mastering your home-brewing technique can be a lengthy and complicated process. So adding yet another step can, admittedly, be intimidating. However, blooming your coffee is not only pretty straightforward, but doing so is totally worth it. 

The science behind coffee blooming is quite intriguing. Understanding why you should bloom your coffee takes away any guesswork about whether or not it’s a step you should add to your routine. Once you grasp how blooming can impact your coffee and why, brewing an excellent cup of coffee will be at your fingertips. 

Cause and Effect: Trapped Gases

During the roasting process, coffee beans go through various chemical changes. When beans are roasted at high temperatures, they begin to expand and trap gases including carbon dioxide. The trapped gases can have a huge impact on the final outcome once the beans have been ground and brewed. 

Unfortunately, the trapped gases can cause air pockets in the coffee beans. So as the beans are brewed, the air pockets create too much space between the water and coffee grounds. The space can prevent uneven extraction, preventing the brew from reaching its full potential. 


Shortly after the coffee beans have finished roasting, a whole new chemical process called degassing begins. Depending on the roast (dark, light, or medium), the degassing process can begin almost immediately upon roasting and continue until the beans are ground or go stale.  

The quality of the coffee brewed from even the freshest beans is a direct result of how long the degassing process takes. If the degassing process does not fully expel all the trapped gases when it’s time to brew, the gases are going to prevent the full flavors of your coffee from being released.

That’s where coffee blooming comes in.

Why Bloom Your Coffee?

As soon as water touches coffee grinds, they begin to release CO2 and other trapped gases. So, during the brewing process, the excess gases can completely escape. But because CO2 repels water, the water can’t directly touch the grinds and draw out the beans’ natural flavor molecules, altering the flow and flavor of your coffee.

Blooming coffee allows any remaining gases that have not been released during the degassing process to escape before you brew your coffee. By simply adding water to the grinds before you brew, it prevents the gases from standing in the way of the water fully touching the grinds while they actually brew. This gives the water a better chance to fully extract all of the mouthwatering flavors of the beans. 

Mastering Coffee Bloom: Techniques and Tips for Achieving a Good Bloom

Coffee blooming is an efficient, simple way to help your coffee reach its flavorful potential. No matter what method you use to brew your coffee, coffee blooming will still effectively enhance your brew. The process takes less than one minute and can immediately change how you view brewing coffee at home. 

Bloom, Bloom

Now that you know that blooming your coffee is going to completely alter your experience for the better, let’s talk about how it’s done. Coffee blooming really is quite simple:

  • Put your grinds into the coffee brewer of your choice.
  • Pour hot water over your freshly ground coffee beans. Use enough water to make the grinds completely wet, but be careful not to oversaturate them.
  • Wait 25-30 seconds before you begin to brew. You should notice bubbles on the surface (depending on the roast-discussed later) as the gases release.
  • Begin brewing as you normally would.

It really is that simple. However, the brewing method you use and other factors can alter the way you need to approach this process slightly.

Pour Over

When someone talks about blooming their coffee, using the pour over method is typically what they are referring to. While blooming your coffee will improve it, it’s still important to get things right with the rest of the pour over brewing process. 

  • Use medium-coarse, fresh grinds for the best pour over coffee.
  • A ratio of 55 grams per liter is appropriate for this method.

Automatic Coffee Makers

Once you’ve got your water hot (boil it) enough, you’ll want to pour it evenly over your grinds in the filter. Typically, you should allow the grinds to bloom for between 45 and 90 seconds. After you’ve waited at least 45 seconds, you can continue with your normal brewing process. 

French Press

After you’ve ground your coffee beans and boiled your water, you’ll want to put the grinds in your carafe. Then you can pour a small amount of hot water directly over the grounds. Once you’ve waited for them to bloom, you can give them a small stir and move on to brewing.

Consider Before Blooming

While your brewing method is something to consider if you want to try coffee blooming, it’s not the only factor. Other factors like grind size, water temperature, and the coffee-to-water ratio can impact how well blooming works and ultimately how your coffee turns out. 

Grind Size

We grind coffee beans after they’ve been roasted to increase their surface area. Grinding the beans allows more gases to escape before you brew them. It also allows water to touch more coffee and extract more of the natural flavors. 

Using a larger grind size allows water to flow freely and less flavor to release. A medium-coarse grind creates a more even extraction process during the blooming and brewing processes.

Water Temperature

Using hot water can act as a sort of catalyst to increase the speed of the chemical reactions that happen to release trapped gases. So, pouring boiling water directly onto the coffee grounds will expel gases faster than if you use room temperature water. 

Coffee-to-Water Ratio

Getting your coffee-to-water ratio just right is imperative to the blooming process. Not using enough hot water could mean that only part of the grounds are being degassed because they aren’t fully touched. Typically, about twice as much water (2 grams) as coffee (1 gram) or just enough to thoroughly saturate, is perfect.

Troubleshooting Failed Coffee Blooming

Even when you think you’ve gotten everything right, there may be times when your coffee still isn’t turning out quite right. The coffee may still be sour or not smell or look right. Fortunately, most of the time, it’s a simple problem with a simple solution. 

Coffee Bloom IssuePossible CauseSolution
Lack of bloomStale coffee beansUse freshly roasted coffee beansUse within 2-4 weeks of being roasted
Lack of bloomIncorrect grind sizeAdjust the grind size based on your brewing method
Lack of bloomWater temperature too lowBoil the waterEnsure the water temp is between 195℉ (91℃) and 205℉ (96℃)
Uneven bloomUneven water distributionPour water slowly and evenly to ensure it reaches all grinds
Uneven bloomCoffee grounds not leveledMake sure the coffee grounds are leveled before adding water
Excessive bloomCoffee beans too freshAllow beans to rest a few days after they are roasted before using them
Excessive bloomToo much coffee for waterAdjust coffee-to-water ratio based on your brewing method
Inconsistent bloom (from one bloom to another)Inconsistent grind sizeAdjust grinderUpgrade grinderEnsure your grinder is producing consistent grind sizes
Inconsistent bloomVariations in water temperatureUse a kettle with temperature control Check temperature of water before using
Inconsistent bloomInconsistent brewing techniquePractice your brewing technique to achieve more consistent results


Our routine morning cup of coffee affects all aspects of our day. So, if your experience with coffee is awful and just doesn’t taste right, it can really take a toll on your day. While it can be an inconvenience to add another step to your brewing process, blooming your coffee really is worth the time it takes.

Blooming your coffee can help improve its taste and reach its amazing, flavorful potential. It’s important to practice your blooming technique and brewing method to be successful. Enjoy your coffee and share with us your experiences, tips, and tricks for coffee blooming!

Christopher Mize

Leave a Comment

Your email address will not be published. Required fields are marked *