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So you’ve been reading a lot about coffee and you’ve noticed the term coffee bloom, but you’re not entirely sure what it is. So what is coffee bloom? Before I jump into the definition, I will quickly go over coffee degassing and how CO2 affects your coffee.


We can all agree that we love fresh coffee, right? Well, unfortunately, one of the minor drawbacks to fresh coffee is Carbon Dioxide. Carbon Dioxide forms in every coffee bean, and it’s during the roasting process, that the CO2 starts to come out. The longer you roast the beans the less carbon dioxide there will be.

Cooling Coffee Beans

After you finishing roasting your coffee beans, the coffee beans go into a “degassing” process. The majority of the carbon dioxide is released within the first 24 hours after the roasting process, and then this process gradually decreases for the next 14 days. When you choose to grind your beans, you increase the release of the CO2. It’s important to let the beans degas over the recommended duration because if the CO2 fully escapes the bean, then the flavour will follow. Leaving you with stale coffee. That’s why it’s best to grind your beans right before you brew.

The presence of Carbon Dioxide in coffee beans is a sign of freshness. 

The CO2 does good for our beans right until we have to brew, the gas negatively affects the coffee in two ways. It makes the coffee taste sour and it affects the extraction process by making it hard for the water to come in contact with the coffee, preventing it from extracting all the goodness out of your brew. This is when coffee bloom steps in.

What is Coffee Bloom? 

Coffee bloom occurs when you pour a small amount of water over your ground coffee and let it sit for a short period, preferably half a minute. During this process, the ground coffee will swell and bubble. These bubbles are a sign of carbon dioxide escaping your coffee.

Coffee Bloom Filter

How to Bloom Coffee

While there are various ways to bloom your coffee, the concept remains the same throughout each process.

The Pour Over Coffee Bloom Method

The process of blooming coffee is extremely popular among pour-over brewing systems. Since the water passes through the grounds extremely fast, it is important for you to bloom beforehand so you don’t lose out on all the coffee flavours. 


To bloom pour-over coffee: 

  • 1: Fill your Pour-over coffee filter with freshly ground coffee.
  • 2: Carefully pour the hot water in a circular motion over the ground coffee so that you slightly soak up all the grinds. (For a controlled and effective pour, use a gooseneck kettle)  
  • 3: You should see the grinds bubble up, this is the result of the CO2 leaving the coffee.
  • 4: Wait half a minute during this process.
  • 5: Proceeded with pouring the rest of the measured water for your brew. 

The French Press Coffee Bloom Method

A classic way to brew your coffee and blooming is extremely easy. With this process, you just incorporate it into your brewing time. So before you brew your coffee for 4 mins, you will bloom the grounds for 30-40 seconds. 

To bloom french press coffee: 

  • 1: Fill your carafe with freshly ground coffee.
  • 2: Pour your hot water over the grounds, just enough to soak up them up. 
  • 3: The grounds should bubble up, as the gas emits 
  • 4: Wait 30-40 seconds during this process
  • 5: Pour the remaining water for your brew and start your brew timer
  • 6: With a minute left to your brew, stir your coffee gently

If you want to know more about the steps of brewing coffee with the french press check out our guide here

The Automatic Drip Machine Coffee Bloom Method

Many coffee brewers love using the automatic drip machine for its quick convenience, so adding an additional step to the mix might be a nuisance, but I assure you that you won’t regret it.

To bloom drip-machine coffee: 

  • 1: Fill your coffee filter with freshly ground coffee
  • 2: Boil some fresh hot water and pour it slowly over the ground coffee, making sure you cover all the grounds. (Make sure you have the carafe in the machine, to catch any water.) 
  • 3: The grounds should bubble
  • 4: Wait about a minute to a minute and a half during this process.
  • 5: After the process is complete, proceed to start your machine. 

The Manual Espresso Coffee Bloom Method

The coffee bloom process on the manual espresso is a bit different from the other methods, though the concept is the same, its referred to as “pre-infusion”, this process helps the coffee swell up in the portafilter, guaranteeing maximum contact with the water and resulting in a richer espresso flavour. 

Manual Espresso Press

To bloom manual espresso: 

  • 1: Fill your portafilter with coffee and lift the lever so it can latch into position.
  • 2: Let the filter basket fill with hot water for about 15 seconds. 
  • 3: Do a 15 second half pull, expect a slight trickle. 
  • 4: Lift the lever and proceed with a full 30-second pull. 


So now that you are a coffee bloom expert, you can successfully rid CO2 from your brew and enhance its delicious flavors. Along with this, it’s important that you keep your coffee stored properly in an airtight container, somewhere cool and dry. A cool temperature is ideal because heat will emit gas leaving your beans stale. Also, make sure to avoid humidity for it can cause mold to grow in your beans, resulting in toxic coffee! 



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