Back To Basics: The ABCs of Coffee Bloom

Looking to improve your brew? Understand what a coffee bloom is first.

Introduction

“Riiiiiing…!” What is the first thing you do after you roll out of bed and hit that alarm? For us, it’s coffee… A beautiful cup of freshly brewed coffee! While, of course, brewing an excellent cup of coffee can be as simple as pouring hot water over coffee grounds, there are many ways to improve your brew. One of these is to understand the fundamentals of brewing, so to start, let us tell you all about the coffee bloom.

What exactly is a coffee bloom?

In scientific terms, it’s the quick bubbling up and release of carbon dioxide from coffee grounds that occurs when freshly roasted coffee is brewed. This is because water accelerates the release of carbon dioxide. In layman terms, a coffee bloom is the fast release of gas (carbon dioxide) that occurs when hot water comes in contact with fresh coffee grounds.

Allowing your coffee to bloom improves the flavour of your coffee by releasing carbon dioxide, which is a water repellant, therefore allowing water to fully extract more of the flavour profiles in a coffee. Carbon dioxide also tastes slightly sour, so not allowing your coffee to bloom could allow some of that sour taste into your brew.

Tip: If your coffee isn’t fresh, there may not be any signs of a “bloom”.

How do you create a coffee bloom?

A coffee bloom happens magically! You can see this more clearly when using the pour over method.

Once your dripper and coffee is set up, start pouring hot water from the centre of your coffee filter, over the top of coffee grounds. Pour in a circular motion towards the outward sides of your filter and stop when all the grounds have been saturated. Wait for 15 – 30 seconds and watch the bubbles appear. This is the coffee bloom and it happens naturally if your coffee is fresh enough.

Do you need a coffee dripper? Check out our team’s favourite drippers!

Why is the coffee bloom important?

The coffee bloom is the part of the brewing process in which gases from the coffee are released as the water hits the grounds. Allowing your coffee time to bloom can enhance the taste notes of your coffee, making it cleaner and more flavourful. Bloom length can actually affect how your coffee tastes, so experiment with how long you allow your coffee to bloom to see the taste differences.

Tip: If your coffee isn’t blooming, it might mean that your coffee isn’t very fresh and degassing may have already occurred before brewing. This means coffee flavours might be flat and disappointing.

Variables affecting the coffee bloom

There are several essential variables that will determine the outcome of the coffee bloom. Here are the top five:

First of all, the temperature. The higher the temperature, the faster gas will escape from the beans. Keep in mind that you should try to store your beans in a cool environment as heat can cause some of the gasses to escape from the beans.

Secondly, the humidity level. On one end, if it’s too dry, more gas can escape. However, on the other end, high humidity levels may encourage the growth of mould and fungus. As such, you would need to find that ideal level to achieve your coffee bloom.

Thirdly, type of roast. This will have a huge impact on the quality of the bloom. For example, darker Italian roasts are said to undergo less degassing as compared to other types. Longer roasts are also known to degas to a lesser degree.

Fourthly, the origin of the bean. Coffee found in certain regions are known to degas more than others.

Last but not least, the hardness of the bean. Harder beans may make it more difficult for the gas to make its way through the bean and escape.

Tip: When more gas is released, the bloom is generally bigger. This is also an indication that your coffee is fresher.

We hope you’ve enjoyed learning about coffee blooms. Follow the tips above, and you’ll be on your way to perfecting your perfect brew! Good luck and as always. We love learning more too so feel free to share your coffee journey with us.