You may have heard us say ‘let your coffee bloom’.

And you may have been like me, for a long time knowing that it is a good thing, but not knowing why.

Well, today I am here to explain. This will give you much needed insight into why it’s important to bloom, when you should bloom, and why fresh coffee is so important.

When coffee beans are roasted, the heat from the roasting process produces carbon dioxide within the coffee beans. Any organic material for that matter produces carbon dioxide when heated.

Once the beans have been roasted, they will begin to release these gases. This is called “degassing”. The beans will release most of the gas in the first four hours and continue to do so for around fourteen days. This is why your coffee packaging contains a one-way valve, not only for smelling purposes, but so these gases have somewhere to go.

These gases are what bring flavour to our coffee. The fewer gases in your coffee, the staler and older your coffee most likely is. When we ground our coffee, we are increasing the surface area, speeding up the degassing rate, and turning the coffee stale faster. Therefore, it is important to ground your coffee as close to brewing as possible.

If you don’t grind at home yet and are interested in trying, the Rhinowares hand grinder is great for beginners and easily portable. Although it takes a little elbow grease, it’s worth it.

Introducing the ‘bloom’, the fast release of gas that occurs when hot water comes into contact with the coffee grounds. You will notice bubbles forming, and then settling after around 30 seconds.

Okay, so we bloom the coffee to release the carbon dioxide? Yes, but why do we need to release the carbon dioxide?

Great question.

Although carbon dioxide plays an important role in providing the flavour of coffee, it will interfere with water gaining access to the beans. This will result in a weak extraction. We need the water to have as much access to the beans as possible during the extraction process.

The most important time to bloom is when using a brewing method where the coffee has a short amount of contact with the coffee grounds. This includes V60, chemex, AeroPress, and any pour-over. However, with the French press it becomes less important, because the coffee has longer contact time with the water, allowing increased extraction.

Blooming is one of the easiest and most simple steps to better coffee. We hope next time you incorporate this 30-second step into your coffee routine.


Happy brewing!


April 22, 2020 — Kashmira Lal