Roasting, In Practice
| Not one controlled study has ever shown that an RoR crash harms a cup of coffee. Not a weak study. Not a disputed study. None at all, in more than a decade of the whole trade repeating it. |
01 What is actually on the record
There are observations.
A consultant tasted thousands of roasts and noticed that the ones he liked tended to have smoothly declining curves. That is a real observation from a serious practitioner, and it is where the idea began.
There are classroom demonstrations.
Students taste roasts and say whether the curve crashed. The samples are chosen by the person who teaches the idea, the tasters know what they are being asked to find, and the results are not recorded in any form anyone else can check.
There are blog posts and forum threads by the thousand.
Nearly all of them cite each other. Trace any chain back far enough and it ends at the same original observation, not at a measurement.
What does not exist is a controlled comparison.
Roasts matched on time, temperature and final colour, differing only in the shape of the rate curve, tasted blind by people who never saw the graphs, with the results written down. Nobody has published it. In a trade this large, after this many years, that is not an oversight.
02 Why the observations cannot settle it
Crashed roasts are usually short on heat.
The condition that bends the curve is the same condition that leaves the coffee underdeveloped. When two things always arrive together, noticing that the cup is bad tells you nothing about which one did it.
The taster usually knows the answer in advance.
If you roasted the batch, watched the curve dip and then sat down to taste it, you are not evaluating the coffee. Expectation is powerful enough that sensory science built the blind protocol specifically to remove it.
The curve itself is not a stable object.
Rate of rise is calculated from a temperature reading. Probe thickness, probe position and software smoothing all change its shape. Roasters running two sensors on one machine have watched one of them show a crash while the other, on the same batch, showed nothing. You cannot build evidence on a feature that changes with the instrument.
03 There is also nothing for a study to test
Reactions respond to temperature, not to the rate of change of temperature.
The Arrhenius relationship, named for a Nobel laureate in chemistry and in use for more than 130 years, sets reaction rate by absolute temperature. How far a reaction has gone is that rate accumulated over time. Both quantities are unaffected by whether the climb was steeper a minute ago.
During a crash the beans are still heating.
Rising more slowly is not falling. Nothing cools, nothing reverses, and no reaction runs backwards. A batch climbing 12 degrees a minute that slows to 4 is still climbing.
Missing evidence and missing mechanism are different problems.
A missing study leaves a question open. A missing mechanism means there was never a question in the first place. For the crash to matter, someone must first describe a chemical process that reads the second derivative of a thermometer. Nobody has attempted it.
04 Where the burden sits
The claim is not the default position.
An idea does not become true by being repeated in enough courses. The people asserting that a crash damages coffee are the ones who owe a demonstration, and the demand for one is not hostility.
| Offered as evidence | What it is | Why it does not settle the question |
| Thousands of roasts tasted | Uncontrolled observation | Heat, development and curve shape all varied together |
| Students identifying crashes blind | Unrecorded demonstration | Samples selected by the claimant, no data published |
| Widespread industry agreement | Consensus by repetition | Sources cite each other, not measurements |
| Personal experience of bad batches | Anecdote with a known confound | Those batches were short on heat |
The experiment is not expensive.
Any roastery with a machine, a scale and a cupping table could run it in a week. That it has not been run, by anyone, in over a decade of the idea being taught for money, is the most informative fact in this whole argument.
Publish it and this position changes the same day.
Until then, roast by heat, mass and time, and judge the coffee by drinking it.
|
First Penguin Coffee Company Roasting since 2010 and teaching roasting since 2016, from our production facility in Korea. Our coffees are listed under Beans in the top menu. Enquiries: 010-3444-1721 |
Next: judging green coffee, and which of its numbers are worth reading.
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