9.3 Roasting Problems Practical: Too Light, Too Dark, Too Fast, Too Slow
Key Takeaways
The SCA says the Roasting Problems practical evaluates the ability to recognize a correct cupping roast using smell and taste alone.
The SCA standard roast targets a ground Agtron reading of 63, about 58 on whole beans.
The SCA's too-light reference is about ground Agtron 75 (whole bean about 68), and its too-dark reference is about ground Agtron 55 (whole bean about 45).
Too fast means reaching the standard color in half the normal roasting time; too slow means reaching it in twice the normal time.
SCA-102 links too-slow roasting to a baked bean and says batches with underdeveloped, burnt, or baked character should be roasted again.
Every CVA assessment assumes the sample was roasted correctly. If it was not, the cupper is tasting the roast rather than the green coffee. The Roasting Problems practical checks that you can catch this by smell and taste alone — without an Agtron reading or a look at the beans.
What the SCA says
The SCA's preparation page states that the exam "evaluates your ability to recognize a correct cupping roast using smell and taste alone." Its advice:
- Review the "Sample Preparation" section of the CVA Protocol or Standard SCA-102.
- Taste a variety of coffees roasted to a ground Agtron of 63 (about 58 whole bean) to learn the standard cupping roast.
- Compare that standard with coffees roasted too light, too dark, too fast, or too slow.
The sample schedule includes an "incorrect preparation" session on Day 3 and the Roasting Problems practical on Day 5.
The SCA's reference table
| Profile | How to prepare it (SCA) |
|---|---|
| Optimum / standard | Roast to a ground Agtron of 63 (about 58 whole bean) |
| Too light | Roast to a ground Agtron of about 75 (about 68 whole bean) |
| Too dark | Roast to a ground Agtron of about 55 (about 45 whole bean) |
| Too fast | Roast to a ground Agtron of 63 (about 58 whole bean) in half the normal roasting time |
| Too slow | Roast to a ground Agtron of 63 (about 58 whole bean) in twice the normal roasting time |
Higher Agtron numbers are lighter roasts. The too-fast and too-slow references reach the same color as the standard. Only the time — and therefore the heating rate — differs, so color cannot separate them. That is why the exam relies on smell and taste.
How SCA-102 defines the problems
SCA-102 calls a roasting problem a deviation from the roasting method, when batches miss the desired roast-level range or have undergone "too fast" or "too slow" roasting:
- Too fast: a roasting problem due to an excessive heating rate.
- Too slow: a roasting problem due to an insufficient heating rate, which results in the so-called "baked" bean.
Such problems produce samples with underdeveloped, burnt, or baked characteristics. These can affect flavor and impression of quality and introduce noise into the assessment. SCA-102 says these batches should not be used for cupping and should be repeated.
Typical sensory signatures
These are common descriptions used in training; any individual coffee may differ. Build your own references from one green lot.
| Profile | Common sensory signs |
|---|---|
| Standard | Clear origin character; acidity, sweetness, and aromatics in balance; clean finish |
| Too light | Grain-, cereal-, or peanut-like notes; green or vegetal edges; sharper, thinner acidity; lower sweetness; sometimes astringent |
| Too dark | Roasted, burnt, or ashy aromatics; more bitterness; muted acidity and origin character |
| Too fast | Can combine signs of underdevelopment (grainy, vegetal, sharp) with harsher, roasty or scorched surface notes, even at standard color |
| Too slow (baked) | Flat and dull; muted acidity and aromatics; bready, papery, or hollow character, even at standard color |
How to practice
- Pick one green lot with clear, clean character, such as a washed Central American coffee.
- Roast the five references in the table on the same sample roaster. Record charge weight, total time, and color for each.
- Rest all five for 8–24 hours and store them airtight, as SCA-102 requires.
- Cup them unblinded first. Write three words for each roast profile at fragrance, aroma, and liquoring.
- Cup them blind a day later. Have a colleague code the cups and include the standard more than once.
- Repeat with a different lot, because roast defects show differently in a natural, a high-density washed coffee, or a low-density coffee.
Exam technique: smell and taste only
- Start at fragrance. Light roasts often reveal themselves with grainy or vegetal dry fragrance; dark roasts with roasty or smoky notes.
- Use the crust and break. Baked samples often smell flat or bready at the break; standard samples smell vivid.
- Confirm in the cup. Look at acidity (lively or flat?), sweetness (present or hollow?), and finish (clean, ashy, or astringent?).
- Do not rely on visual cues. Too fast and too slow match the standard's color by design.
- Anchor on the standard. If several cups are presented, first find the one that tastes "correct," then classify the others relative to it.
Why roasting problems matter beyond this exam
A Q Grader who misses a roasting problem may blame the green coffee for a flaw the roaster created. For example, a baked roast might be judged as flat, past-crop coffee, or a too-light roast as an unripe harvest. Catching the roast first protects producers and buyers from wrong conclusions. It is also why SCA-102 requires deviations from the standard roast level to be reported to all parties.
A quick decision guide
- Grainy, vegetal, sharp, thin? Think too light, or too fast.
- Roasty, ashy, bitter, little acidity? Think too dark.
- Flat, bready, hollow, at normal color? Think too slow (baked).
- Clear origin character with balanced acidity and sweetness? That is your standard.
What does the SCA say the Roasting Problems practical evaluates?
The ability to operate a sample roaster to a target Agtron reading
The ability to recognize a correct cupping roast using smell and taste alone
The ability to count quakers in a 100 g roasted sample
The ability to read an Agtron meter within one point
In the SCA's reference table, how is the "too slow" sample prepared?
Ground Agtron 63 (about 58 whole bean), in twice the normal time
Roasted to ground Agtron 55 in the normal time
Roasted to ground Agtron 75 in half the normal time
Roasted to ground Agtron 63 and then rested for 72 hours before cupping
Why can't a candidate separate the too-fast and too-slow samples from the standard by color alone?
Because the exam is held under red light
Because Agtron readings and roast meters are not allowed anywhere in the exam room
All three reach ground Agtron 63; only the roasting time differs
Because too-fast and too-slow samples are always darker than the standard
Sections you finish are checked off in the contents.