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How-To Guide

Cocoa Bean Roasting Time and Temperature — Profiles & Calibration

A profile is not a recipe

A recipe says: 300°F for twenty minutes. It describes what you did to the equipment.

A profile says: the beans reach this temperature at this minute, and this temperature at that minute. It describes what happened to the cacao — which means it travels. Hand your profile to someone with a different grill and they can reproduce your roast, because the profile never mentioned the grill.

That portability is the reason it is worth the trouble of building one. It is also why we are not going to hand you a chart of numbers to copy. Your grill, your burner, your ambient temperature and your beans are not ours. What we can hand you is the method for finding your own, which is the part that actually transfers.

Before you start

  • An RK Drum installed on your grill, assembled and test-fired — see the assembly guide if you are not there yet.
  • The RoastPilot controller installed, so you can see bean temperature. Without it you can still roast cacao, but you cannot build a profile, because you cannot see the thing a profile is made of.
  • Enough of one origin to run several batches. Calibration means repetition, and switching beans mid-calibration wastes the exercise.
  • A way to cool fast — a cooler, or at minimum a box fan and a colander. Cacao keeps roasting in its own heat after it leaves the drum. If it takes five minutes to come down, your careful finish temperature was a suggestion.

The calibration roast

Same principle as the coffee calibration roast: start small, so a batch you get wrong costs you very little, and learn what your particular setup does before you commit real beans to it.

  1. Charge small. Run roughly a quarter of the drum's rated capacity for the first batch. You are learning the equipment, not making chocolate.
  2. Preheat and note the number. Bring the drum up and let it stabilise. Write down the grill temperature you charged at — it is the first thing you will adjust.
  3. Load and start the clock and the log together. RoastPilot begins recording from the moment you start the session; get in the habit of starting both at once.
  4. Watch for the moisture plateau. Bean temperature will climb, then flatten as the water boils off, then begin climbing again. That inflection is your landmark — the one cacao does give you, if you can see it. Note the minute it happens.
  5. Steer the rate of rise, not the target. Once past the plateau, your job is the steepness of the climb. Adjust the applied heat to keep it moving steadily; do not chase the end temperature by lunging at the gas.
  6. Finish on a temperature, not a timer. Pull when the beans reach the number you are aiming for. Note both the temperature and the minute it arrived.
  7. Cool immediately and hard. Then write down what you would change.

Three or four of these and you will know your setup: what charge temperature gets you a sensible drying phase, how much gas holds a steady climb, and how long the whole thing takes at your batch size. That is your baseline profile. Save it in RoastPilot and it becomes the curve every future roast is measured against.

The three phases, and what to change

PhaseWhat is happeningIf it goes wrong
Drying Moisture leaving the bean. Temperature climbs then flattens near the boiling point of water. Too fast and you scorch a bean that is still wet inside — grassy or harsh notes. Too slow and you bake it flat before development starts.
Development Past the plateau; Maillard reactions build chocolate flavour. Bean temperature climbs steadily. Too fast and the outside develops ahead of the inside. Too slow and the aromatics you were after are driven off before you finish.
Finish Arriving at your end-of-roast bean temperature. Finish low and the chocolate reads raw and acidic. Finish high and you lose origin character to generic roast.

Where to aim

Published cacao practice splits between a hot-and-short roast — around fifteen to twenty-five minutes, finishing roughly fifty to sixty degrees Fahrenheit above the boiling point of water — and a long-and-low roast of forty-five to sixty minutes reaching a similar place more gently. Charge temperatures well above the finish temperature are normal, because you are loading cold wet beans into a hot drum and want the drying phase to get moving.

Use that as the region to explore on your first calibration batch, then let your own results move you. Origins differ. A bean you intend to make into a 70% bar and a bean you intend to brew do not want the same treatment.

Recording it so it is worth something

A profile you cannot reproduce is a nice memory. For each roast, keep the charge weight, the charge temperature, the minute the moisture plateau broke, the end-of-roast bean temperature, the total time, and one line on how it tasted once it was chocolate. RoastPilot keeps the curve, the session history and the export; the tasting note is the part only you can add, and it is the one that makes the file worth reading in six months.

Roasting cacao commercially? Batch size changes the arithmetic and the drum spec is worth a conversation. Email us — we have built drums to customer specification for cacao before.

Common questions

What is a calibration roast?

A deliberately small first batch — roughly a quarter of the drum's rated capacity — run to learn what your specific grill, burner and drum do, rather than to make good chocolate. You note the charge temperature, when the moisture plateau breaks, the end-of-roast bean temperature and the total time, then adjust and repeat. Three or four gives you a baseline profile.

How long should a cacao roast take?

Published practice runs roughly 15–25 minutes for a hot-and-short roast, or 45–60 minutes for a long-and-low one. Both are valid and produce different flavour. Time is an outcome of your profile, though — you finish on a bean temperature, not on a timer.

Why do I need to cool cacao quickly after roasting?

Because the beans carry enough heat to keep roasting themselves after they leave the drum. If cooling takes several minutes, the end-of-roast temperature you carefully hit is not where the beans actually finished. A cooler, or at minimum a box fan and a colander, keeps your finish temperature meaningful.

Can I use someone else's cacao roast profile?

As a starting point, yes — that is the advantage of a profile over a recipe, since it describes bean temperature over time rather than equipment settings. You will still need a calibration roast to learn what applied heat produces that curve on your own grill.

Keep reading

We build roasters, not chocolate

Worth saying plainly, because it shapes what you should and should not ask us.

We are a machine shop. We have spent twenty years building drums that apply controlled heat to beans and let you see exactly what that heat is doing — for coffee, cacao, peanuts, nuts and grain. Ask us about drums, grills, burners, motors, thermocouples, profiles, batch sizes, or why your roast is running away from you at minute nine, and you have our full attention.

We are not chocolate makers. Fermentation, origin selection, winnowing technique, refining, conching, tempering, recipes — that is a craft in its own right and not ours.

For that side, Chocolate Alchemy is the best resource on the internet and has been since 2004. John Nanci's complete bean-to-bar guide, his 300-plus Ask the Alchemist archive and the Chocolate Alchemy forum will take you further than we could. We send people there happily and often — and if you want to learn profile drum roasting hands-on, they run an all-day drum roasting seminar that is worth the trip.

Get your chocolate craft from him. Get your roaster from us.

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