Coffee roasting profiles

A roast profile is the recipe a roaster follows and the record of what actually happened: a line showing how hot the beans were at every moment of the roast. Time runs along the bottom of the graph, temperature up the side, and the curve is drawn live by probes sitting inside the machine.¹²

Peer-reviewed work uses the same plain definition — a roast profile is “the temperature versus time measured inside the roaster during roasting” — and treats it as the thing that steers the chemical reactions, and therefore the flavour and aroma.³ A trade guide puts the working version more loosely: “a set of parameters that define how a coffee should be, or has been, roasted.”²

The distinction worth holding onto is that Coffee roasting covers where the roast stops — light, medium, dark, first and second crack. A profile covers how it got there. Two roasters can drop at exactly the same temperature by two completely different routes and get two different cups.

What the curve is made of

Almost every profile is drawn from two thermometers and a clock.¹²

Parameter	What it is	Why it matters
Charge temperature	The machine temperature at the moment green coffee is tipped in	Sets how much stored heat the beans get in the first seconds; the profile’s starting point
Bean temperature (BT)	A probe immersed in the bean pile inside the drum1	The main line on the graph — the roast, as the coffee feels it
Exhaust / environmental temperature (ET)	A probe reading the outgoing air12	Reacts to a gas change almost immediately, so it hints at where bean temperature is heading next
Turning point	The moment bean temperature “stops falling and begins to rise”1	Cold beans chill the probe first; this is where the roast really starts climbing
Rate of rise (RoR)	How fast bean temperature is climbing, degrees per unit time — “an indicator of roast momentum”1	The shape of the roast, more than any single temperature
First crack	Trapped moisture flashes to steam, the bean expands and audibly cracks open14	The one landmark every roaster navigates by, at roughly 196 °C / 385 °F2
Development time	The stretch after first crack until the beans are dropped1	Where roast character is finally set
Development time ratio (DTR)	Development time as a percentage of total roast time1	Lets you compare a 9-minute roast with a 14-minute one
End (drop) temperature	Bean temperature when the beans are dumped out to cool1	The number most closely tied to light/medium/dark
Total roast time	Charge to drop	The other half of every ratio on this list

A roaster also logs the settings that caused the curve — gas or heat input, airflow and drum speed — because the curve alone doesn’t tell the next person how to reproduce it.²

Some rough anchors from one green-coffee supplier’s roasting guide, to make the numbers concrete: charge at 385–400 °F on a single-walled gas drum, or 430–440 °F on a double-walled machine; a light roast reaching first crack around 8–9 minutes, dropping near 400 °F at 10–12 minutes total, with a DTR target of 16–20%.¹ That drop temperature sits just above the 385 °F first-crack landmark, which is the right side of it — the Coffee roasting note flags a competing published “light roast” range whose bottom half would end the roast before first crack ever happened.

Reading the shape

The single most-discussed feature of a profile is not a temperature at all — it is whether the rate of rise falls smoothly. Roasters aim for a “steadily declining RoR, which creates balanced flavor development”: fast at the start, gently easing off all the way to the drop.¹

Two failures have names, both visible as kinks in the RoR line:

• A flick — the line jumps back up, usually around first crack, as the bean’s own reactions start giving off heat.
• A crash — the line drops away sharply, and the roast stalls out.

Neither is a temperature you’d notice on the bean-temperature curve itself, which is exactly why RoR gets its own plot. A roast can look perfectly smooth on the main line and be lurching underneath.

The three stretches a profile is divided into — drying, browning (where the Maillard reaction runs) and development — are described in Coffee roasting.

To verify — the famous phase percentages are not a standard, and the sources disagree

Practice guides commonly say the drying phase should be around 30–40% of total roast time. The Coffee roasting note already flags a competing and widely repeated split of roughly 50% drying, 30% browning, 20% development, whose only traceable source is a forum thread of roasters comparing notes. For development specifically, the supplier guide consulted here targets 16–20% DTR,¹ against the 16–25% circulating in that forum thread. The ranges overlap, so nothing here is flatly wrong — but none of these figures is published by the SCA or CQI as a standard, and all of them shift with machine design, batch size and bean density. Treat them as orientation, not targets.

What the science actually shows

The best-documented experiment on profiles is a 2024 Scientific Reports paper by Anokye-Bempah and colleagues, which measured titratable acidity — a lab measure of how much acid is in the coffee — continuously through commercial-scale roasts.³

The design is worth stating because it is unusually concrete for this subject: seven named profiles (Fast Start, Slow Start, Medium, Production, Exaggerated Flick, Negative Rate of Rise and Extended Maillard) run on three coffees — a washed Ugandan Sipi Falls, an El Salvador Ataco honey, and a washed Sumatra — on a 5 kg natural-gas Probat P5 drum roaster, across 39 roasts yielding 663 samples.³

The headline result: peak acidity always arrived at first crack, at an average of 4.9 ± 0.2 mL NaOH per 40 mL sample, and it did so regardless of which profile was used or where the coffee came from.³

That is a genuinely useful finding for a roaster. It means first crack is not just an audible convenience — it is a real chemical turning point, and the profile’s job around it is deciding how much of that acidity to keep or burn off, not whether the peak happens.

To verify — the "dense beans need a hotter charge" rule

A common claim in roasting guides is that coffees with higher density and lower moisture — typically higher-altitude lots — need a higher charge temperature and more energy early to develop properly without scorching or tipping. It appears in the research behind this note only via a blog and a video, with no primary or peer-reviewed source, and the Scientific Reports study above did not test it.³ Widely believed practitioner guidance; not established here. Terroir and Water activity cover the green-bean side of the same argument.

Profiles as shareable data

Once a roast is a dataset rather than a memory, it can be filed, compared and sent to someone else. Logging software such as Cropster records the probes and draws the curve in real time so the roaster can adjust mid-roast, and the guiding principle is blunt: “the more data you can capture during the roasting process, the more accurate and consistent your roast profile will be.”²

Sharing goes a step further. Roest, a Norwegian sample-roaster maker, launched a Public Profile Library on 7 March 2023 — a portal where owners of its machines upload profiles for others to download and re-run.⁵ Profiles carry searchable metadata including description, origin and process; Roest itself tests and verifies some uploads, which then display a badge, alongside download counts and star ratings.⁵

The library makes the point that a profile is not only a curve. Without knowing which coffee it was drawn on, how it was processed and what it was aiming for, the line is just a shape.

It also has a hard limit: a profile is only directly reproducible on the same machine. Drum mass, burner design and probe placement all differ, so a curve from one roaster is a description of intent on another — which is why the library is organised around one manufacturer’s equipment rather than being a universal archive.⁵

Where profiles show up in the trade

• Sample roasting — the deliberately plain, tightly standardised profile used to judge green coffee rather than flatter it, and the reason a roast log gets filed next to a cupping scoresheet.
• World Coffee Roasting Championship — the whole middle stage of the competition is finding a profile on small batches and then reproducing it at production volume, and competitors are interviewed on their reasoning as well as scored on the cup.
• Green coffee buying — a buyer approving a lot is implicitly approving a profile that made it taste that way.
• Agtron scale — the colour reading used to check that a profile landed where it was supposed to, since “medium” is not a measurement.

One thing you will not find: published roast curves for competition or auction lots. Green-coffee auctions such as Best of Panama and Cup of Excellence publish lots, scores, buyers and prices; roasting competitions publish names and scores. Neither publishes the profile graphs, and no source consulted here contains them. Any note tying a specific auction lot to a specific documented roast curve would be invented.

Related

• Coffee roasting — where the roast stops; this note is about how it gets there
• Sample roasting — the standardised profile used as a measuring instrument
• Maillard reaction — the browning chemistry the middle of every profile is steering
• Agtron scale — measuring the result instead of describing it in words
• World Coffee Roasting Championship — profile design as a competitive sport
• Coffee freshness and degassing — what happens to the beans after the drop
• Loring Smart Roast — a machine maker whose burner design changes what curves are even possible
• Scott Rao — the consultant whose books are the standard written reference on roast curves and declining rate of rise
• Green coffee buying · Green coffee grading · Water activity · Terroir — the green-bean properties a profile is chosen against
• Cupping · Coffee scoring — how anyone finds out whether the profile worked
• Specialty Coffee Association — the body whose roast-level standard is still unpublished

Official links

• Official site — Specialty Coffee Association, Coffee Standards
• Official — ROEST Public Profile Library announcement

Footnotes

1. Genuine Origin — Roast Profiles 101: Everything You Need to Know — confirmed via WebFetch; source of the parameter definitions (charge, BT, ET, turning point, RoR, development time, DTR, end temperature), the declining-RoR aim, the 385–400 °F and 430–440 °F charge ranges, the 8–9 minute first crack, the ~400 °F drop, the 10–12 minute light-roast total and the 16–20% DTR target ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³

2. MTPak Coffee — Coffee Roasting: A Guide To Roast Profiles — confirmed via WebFetch; source of the “set of parameters” definition, the bean/exhaust/heat-input/time data points, the gas-airflow-drum-speed logging, the ~196 °C first crack and the Cropster logging-software point ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷

3. The effect of roast profiles on the dynamics of titratable acidity during coffee roasting — Anokye-Bempah et al., Scientific Reports, 2024 (PMC) — confirmed via WebFetch; source of the temperature-versus-time definition, the seven named profiles, the three origins, the Probat P5 5 kg roaster, the 39 roasts, and the peak-titratable-acidity-at-first-crack finding ↩ ↩² ↩³ ↩⁴ ↩⁵

4. Coffee roasting — Wikipedia — cited via the research report and corroborated in this wiki’s Coffee roasting note; general background on first crack and the named roast degrees a profile targets ↩

5. ROEST — Introducing new: Public Profile Library — confirmed via WebFetch; source of the library’s launch date, the upload/download model, the description/origin/process metadata, and the verification badges, download counts and ratings ↩ ↩² ↩³