Degassing: Why your freshly roasted coffee needs a "rest"

There is nothing like the aroma of freshly roasted coffee. But did you know that coffee can actually be too fresh?

Right after roasting, the beans go through a process called degassing. This is when the coffee releases the accumulated CO₂ gases formed during the chemical reactions in the roaster. If you brew the coffee too early, the gases can block the water and result in a sour, unbalanced cup.

Here is your guide on how long you need to be patient to hit the coffee’s "peak".

The Science: What Happens Inside the Bean?

During roasting (especially during the Maillard reaction and caramelization), large amounts of carbon dioxide are produced. Some escapes during the roasting itself, but the rest is trapped in the bean's porous structure.

The first 24-48 hours: About 40% of the gas is released in a rapid burst.

The following days: The remainder slowly seeps out, allowing the more complex aroma compounds to develop.

SLAYER Espresso Single Group - Den ultimative espressomaskine - BloomVik

When should I brew? (Recommended resting times)

The resting time depends on your brewing method. Espresso is much more sensitive to CO₂ than filter coffee, as the gas creates resistance under high pressure.

☕ Filter Coffee (Pour-over, French Press, Automatic)

Resting time: 3 – 7 days.
Tip: You can often brew after 2 days if you do a thorough "bloom" (pour a little water over and wait 30 seconds), as this helps the gas escape before brewing.

☕ Espresso

Resting time: 7 – 14 days (Peak is often around day 10).
Why? Fresh coffee produces an unstable, bubbly crema and a metallic or sour taste (channeling). Lightly roasted espresso often requires up to 3 weeks of resting to fully develop its sweetness.

3 simple home tests: Is the coffee ready?

You don’t need a laboratory to check if your coffee has rested enough. Try these three methods:

The Bag Test: Place a handful of beans in a ziplock bag and press out all the air. If the bag is puffed up the next morning, the gases are still working at full pressure – wait a few more days.
The Bloom Test: For filter coffee, the coffee should "bubble" moderately when you pour the first drops of water. No bloom means old coffee; a violent, explosive bloom means it needs more resting.
The Crema Test (Espresso): Pull a shot. If the crema is extremely thick but disappears within 10 seconds leaving large bubbles, the coffee is too fresh. A stable, fine-textured, golden crema is the goal.

Take control of your coffee experience

As a home roaster, you have the unique advantage of being able to follow the coffee’s development day by day. We recommend logging your roasts and tasting them regularly – it’s the best way to get to know your beans.

Need equipment to master the process?

At BloomVik, you’ll find everything from precision scales to advanced home roasters and storage solutions with one-way valves that let gas escape without letting oxygen in.

Explore our selection here