What is coffee degassing and how it makes your coffee taste better

Here’s something not every coffee drinker knows: coffee can be too fresh!

Coffee roasters and coffee stores of specialty coffee usually like to make it well known their coffee is roasted fresh and we agree they should. Coffee beans that sit around lose their aromatics and oxidize, which creates stale, far from delicious flavours. That’s why coffee from big grocery stores doesn't measure up to high-quality coffee.

No matter how good your storage or how many tricks people try to promote on social media, coffee that is enjoyed within a reasonable period of time after roasting will always taste better and more dynamic than coffee that sits in your cupboard for months.

But while fresh is good, too fresh isn't.

The process of roasting coffee naturally increases the carbon dioxide levels inside the coffee beans. This gas starts to leak immediately after roasting and it’s the reason coffee bags have that plastic circle with a tiny hole in it. This mark is a one-way valve to help the coffee rest. It lets the carbon dioxide release from the beans out, while not letting any oxygen in - which helps keep your coffee as freshest as it can be.

If you ever brewed coffee in a pour-over, Chemex, French press or any other method where you can see the hot water flowing into the coffee, you probably noticed the ground coffee starts to bubble gently. Guess what those bubbles are - that’s carbon dioxide!

Don’t be alarmed, there’s nothing wrong or harmful with carbon dioxide being in your coffee, but too much does make it harder to extract the best flavour from it.

When hot water gets in contact with the coffee grounds they start releasing all the good compounds that end up in your cup. If there’s too much gas pushing out from the coffee grounds, it’s simply harder for that water to get in. The result is oftentimes a cup too acidic, too bitter, or both.

That’s why when brewing coffee by methods such as pour-over, Chemex, or French press it is encouraged to let the grounds bloom. Blooming is how it is called the process of pouring just enough hot water to wet the coffee grounds and letting it sit for 30 to 45 seconds before pouring the rest of the water.

While a coffee bloom can surely improve and fine-tune your cup while brewing, its impact is reduced if the coffee is too fresh and did not have enough time to lose carbon dioxide between roasting and brewing. This resting period is called degassing or off-gassing.

How to degas your coffee

Here’s the good news, degassing coffee does not involve anything fancy or complicated. It simply means you should let your coffee rest on your counter for a few days after roasted, ideally still in its original bag. All Portfolio coffee have the roast date stamped on the coffee bag to help you with degassing at home. Aim for 5 to 7 days from the roasting date for optimal flavour and experience.

If your preferred brewing method involves longer contact between coffee grounds and hot water you could probably enjoy it at its peak sooner, but if espresso is your go-to coffee cup degassing is especially important. This is because while pulling an espresso shot, the coffee grounds are packed too tightly and there is not enough time to even allow for a bloom.

If you use coffee that hasn’t degassed for long enough when brewing espressos, it can take longer to pull a shot because the gases hold back the water. While the carbon dioxide can trick you by producing a bubbling crema, the end result will be suboptimal as the extraction has been interrupted.

Roast profile affects degassing

Generally speaking, dark roasts have a degassing process that is faster than light roasts. This is because the beans have more tiny cracks that let the carbon dioxide escape while lighter roasts keep the beans more intact.

Conclusion

Always prefer fresh roasted coffee over grocery store shelf coffee. When buying fresh coffee, check the roast date on the coffee bag and aim for 5 to 7 days from the original date to brew your first cup. This is when your coffee will reach its peak flavour and you’ll get to enjoy the best brew.

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