The Coffee Roasting Process, Explained by Our Roaster

Roasting is cooking, not heating

Green coffee is a seed. It's dense, grassy, and tastes like nothing you'd want to drink. Roasting is the chemistry that turns stored sugars and acids into the several hundred aromatic compounds you smell when a fresh bag opens.

Gundobad — the roaster behind every Wolfmilk batch — describes his job in one line: *"I'm not heating beans. I'm cooking sugar, and I only get one shot per batch."*

Here's the whole arc, stage by stage.

1. The charge

The drum gets pre-heated, then the green coffee drops in. Bean temperature crashes immediately — that low point is the turning point, usually around 30–60 seconds in.

Charge too hot and the outside scorches before the inside is cooked. Charge too cool and the batch stalls, which bakes the sugars flat. The charge temperature is the first real decision, and it changes with bean density, moisture content, and how cold the roastery is that morning.

2. The drying phase

For the first several minutes the beans shed moisture — from roughly 11% down to 2–3%. They go from green to yellow and smell like hay and toast.

Nothing tastes good yet. This phase exists to get heat evenly into the bean so the flavor development that follows happens all the way through, not just on the surface.

3. Maillard and caramelization

Once the water's mostly gone, the browning reactions start. Maillard reactions (amino acids plus sugars) build body, nuttiness, and savory depth. Caramelization breaks sugars down into sweetness and the darker, richer notes.

This is where a roast gets its personality. Stretch this phase and you get a rounder, heavier cup. Rush it and you get thin coffee that tastes sharp no matter how well you brew it.

4. First crack

Steam pressure inside the bean finally wins and the bean pops audibly — like distant popcorn. First crack is the line between "green" and "coffee." Everything before it is preparation; everything after it is flavor.

Gundobad roasts by ear here. No profile-recall button, no automation. He listens for the first pops, then for the rolling crackle, then for it to thin out.

5. Development time

The stretch between first crack and the drop is development time — the most important number in the roast. It's usually 15–25% of total roast time.

• Too short: underdeveloped. Sour, grassy, thin. People blame their brewer for this cup.
• Too long: flat. Origin character burns off and everything tastes like generic "roast."
• Right: the origin still speaks, the sweetness has arrived, the acidity is bright instead of sour.

Our medium roast drops mid-development. Our dark roast rides further toward second crack for a heavier, chocolate-forward cup — but never into ashy territory.

6. The drop and the cool

Beans dump into the cooling tray and get pulled to room temperature fast. Slow cooling means the beans keep roasting on residual heat, which quietly undoes careful work.

7. The rest

Fresh-roasted coffee is full of CO₂. Brew it same-day and the gas fights water absorption — you get uneven extraction and a weirdly sour cup. Coffee wants 3–5 days of rest, then holds its peak for a couple of weeks.

That's why we roast on Wednesdays and ship right after: you receive it as it's entering the window, not leaving it.

Where most roasts go wrong

1. Baking. Not enough heat momentum through the middle. Bread-like, dull coffee.
2. Scorching. Too much heat too early. Charred surface, sour center.
3. Underdevelopment. Dropped too soon after first crack. The most common defect in "light roast" coffee that tastes bad.
4. Roasting for shelf life. Dark, oily, uniform beans hide old green coffee and survive months on a shelf. That's a logistics decision, not a flavor one.

Read this on the bag

A roaster who's proud of the process tells you the origin, the roast level, and — critically — the roast date. If you only get a "best by," the roast was built for the warehouse, not for you.

Meet Gundobad and see how he works, or take the 90-second quiz and we'll match you to the roast level that fits how you brew.