Everyone forgets to let their dark roast beans sit for at least 5 minutes after grinding

I noticed at my local cafe in Austin that their dark roast shots tasted burnt and sour until I started waiting 5 minutes after grinding, and now my own brews at home are way smoother, has anyone else tried giving their grounds time to degas?

3 comments

3 Comments

gonzalez.reese15d ago

I read somewhere from a roaster in Portland that dark roast beans need that time to let the carbon dioxide escape, otherwise it messes with the extraction. At 30 seconds after grinding, the CO2 is still super high and it pushes water away from the grounds, so you get an uneven brew. Waiting those 5 minutes lets most of the gas release, and then the water can actually soak into the coffee evenly. I tried it with a bag of Sumatra I got from a farmers market and the difference was night and day, the burnt bitterness basically disappeared. Have you noticed a big change in the crema too?

lopez.karen15d ago

Try letting it sit for less time and see what happens. I usually wait about 3 minutes for dark roast beans, and that works fine for me. The CO2 releases fastest in the first couple minutes anyway. If you wait the full 5, you might be losing some of the better flavors, especially with a lighter dark roast. Also make sure your grinder is giving you a consistent particle size, because uneven grounds can cause the same channeling issues as too much CO2. I do notice the crema gets thicker and darker when I wait, but it also depends on how fresh the beans are. Fresher beans always give me more crema regardless of resting time.

bennett.noah15d ago

The waiting thing does help but it's more about the roast level than the bean origin. Dark roasts have way more CO2 trapped because the bean structure gets opened up more during roasting. You might be overdoing it with 5 minutes though, 2-3 is usually enough for most dark roasts. I've found letting it sit too long can actually let some of the finer aromatics fade out, especially if the bag's been open a while. Crema wise yeah it gets thicker and more stable when I wait, but Sumatra blends tend to have heavy crema anyway so that part could be the bean itself.