Why We Let Coffee Rest After Roast (the Three Days That Change the Cup)

If you've ordered from us and brewed the coffee the day it arrived, you may have noticed that the cup tasted different from what we described. It wasn't the coffee. It was the resting.

This is the inside view of why we ship coffee that has rested for a few days, what resting actually does to the cup, and how to time your brewing around the rest.

What resting is

Resting is the period between roasting and brewing. The coffee sits in the bag (or in an open container) for a few days after the roast, and during that time, the cup changes.

The change isn't dramatic — it isn't like a wine that goes from bad to good over years. It's a slow adjustment in the cup's character over a 2-5 day window. Most specialty roasters recommend letting coffee rest for at least 2-3 days before brewing, and our own shipping schedule is set up so the coffee you receive has rested for 3-7 days.

Why the cup changes

Three things are happening inside the beans after the roast:

• Degassing. The beans are releasing the CO2 that built up during roasting. A freshly-roasted bean is full of CO2 under pressure; over the first few days, that gas escapes through the bean's pore structure. If you brew with too much CO2 still in the beans, the gas interferes with water contact in the brew bed, and the cup comes out thin and uneven.
• Maillard completion. The chemical reactions that produce coffee's flavor compounds during roasting continue for a short time after the roast ends. Most of these reactions slow significantly within an hour, but some of the aromatic complex esters take a day or two to finish developing. The result is that the cup gets more aromatic and more complex in the first 48 hours after roasting.
• Equilibration. The moisture content inside the bean equalizes. After roasting, the outer layer of the bean is drier than the center. Over a few days, moisture moves from the center to the surface, and the bean becomes more uniform. This affects extraction.

The three processes overlap, and the net effect is that the cup goes through a curve: too-fresh (0-2 days), peak (3-14 days), declining (14-35 days), and past-peak (35+ days).

How we time it

We roast on Wednesdays and ship on Thursdays. The bag you receive will have a roast date of the previous Wednesday (or the Wednesday before that, depending on when you ordered).

If you order on Wednesday afternoon or later, your bag has a roast date of 7 days earlier. If you order on Thursday morning, your bag has a roast date of 1 day earlier (we shipped the same roast to other addresses the previous day). The bag you brew has rested for somewhere between 1 and 7 days.

Most of our customers brew the coffee within a week of receiving it, which puts the brew squarely in the peak window (3-14 days post-roast). Some customers let the bag sit for a couple of days after receiving it before opening, which pushes the brew further into the peak window.

How to read the degassing curve

If you've ever brewed a coffee right after roasting and noticed a slight bready or papery note, that was the CO2. The note fades as the CO2 leaves the beans. Most coffees have lost enough CO2 by day 3 to brew cleanly.

The exception is darker roasts. A dark roast generates more CO2 during roasting, and it takes longer to degas. A dark roast may need 5-7 days of rest before it brews cleanly. We usually recommend that customers with darker roasts in our catalog brew them 7-10 days after the roast date.

What to do if you want to brew right away

If you've just received a bag and you want to brew it today, you can. The cup won't be at peak, but it won't be bad. A few things that help:

• Pour a little slower. A slower pour gives the water more time to displace the CO2 in the brew bed. The cup is more even.
• Use a slightly finer grind. A finer grind gives you more extraction in the available brew time. The cup is more developed.
• Use more coffee. Bumping the dose up by 10-15% compensates for the cup being thinner. The cup is fuller.
• Skip the bloom step, or do a longer bloom. A 60-90 second bloom is more effective at degassing a fresh coffee than a 30-second bloom.

None of these will fully compensate for a fresh coffee that's been brewed too soon. The cup will still be slightly thinner and less aromatic than it would be at peak. But if you can't wait, these help.

How to tell if the coffee is past peak

A coffee past peak has lost its bright aromatics and has started to lean woody or flat. The body holds, but the cup doesn't have lift.

A few ways to read the coffee:

• The smell test. Open the bag and smell the grounds. If the aromatics are still bright and the coffee smells like the coffee, it's in the window. If the grounds smell slightly flat or papery, it's past peak.
• The bloom test. Pour just enough water to wet the grounds and watch the bloom. A fresh coffee blooms aggressively (CO2 pushes the grounds up). A coffee at peak has a modest bloom. A coffee past peak has almost no bloom.
• The cup test. Brew a cup. If the cup is bright and clean, you're in the window. If the cup is flat and slightly woody, you're past.

What resting does to specific coffees

Different coffees rest differently. A few notes from our catalog:

• Light single-origins. A Yirgacheffe or a Kenya benefits from 3-5 days of rest. The aromatics develop more in the first few days.
• Medium single-origins. A Colombia or a Costa Rica benefits from 2-4 days. They're more forgiving on timing.
• Dark roasts. A French roast or a Vienna roast benefits from 5-7 days. The degassing is slower.
• Blends. Blends usually benefit from a slightly longer rest than single-origins, because the components need to equilibrate together. 3-5 days is typical.

The exact timing depends on the coffee and your taste preferences. If you're not sure, try brewing the same coffee at 3 days, 7 days, and 14 days post-roast. You'll develop a sense of when you prefer it.

A note on espresso

Espresso behaves differently than filter coffee when it comes to resting.

A few notes:

• Fresh-roasted espresso is even harder to brew than fresh-roasted filter. The high pressure of an espresso machine exaggerates the CO2 problem. A 1-day-old espresso can be a soup of crema that tastes thin.
• Espresso benefits from a longer rest than filter. Most espresso roasters recommend 7-10 days of rest, compared to the 2-4 days for filter. The bean needs more time to degas.
• We rest our espresso blends for 7 days at the roastery. This is built into our shipping schedule — if you order our espresso, the bag has a roast date of 7 days earlier.
• Single-origin espresso needs even more rest. Some single-origins need 14 days or more to settle. We don't have a single-origin espresso in our current catalog for this reason.

If you're brewing espresso at home and the cup is foamy and thin, the coffee may be too fresh. Try waiting 7-10 days after the roast date.

P.S. If you've ever opened a bag of fresh coffee and wondered why the cup didn't taste like what we described, the answer is almost always resting. Brew the same coffee a week later, and you'll see what we mean.

— Seraphina