Development time and roast logging: the business case
Every batch you do not log is a batch you cannot repeat, explain or improve. What to log, how development time fits in, and what good records save in money and time.
6 min read Updated 9 October 2026
Development time is the time from the start of first crack to the drop. Many roasters also track development time ratio (DTR): development time as a share of total roast time. It is one of several useful markers for comparing batches of the same coffee; it is not a quality score on its own.
What a roast log should hold
Per batch
- Date, time, roaster and operator
- Coffee, green lot and charge weight
- Charge temperature and settings
- Bean and exhaust temperature curves
- Events: turning point, end of drying, first crack, drop
- Gas or power and airflow changes
- Roasted weight (for roast loss) and colour
- Notes and any deviation
The business case
| Benefit | Where it shows up |
|---|---|
| Consistency | Fewer complaints and lost wholesale accounts |
| Training | New roasters follow reference curves instead of shadowing for months |
| Fault finding | A drifting probe, a dirty fan or a wet lot shows in the curves |
| Cost | Roast loss and energy per batch measured, not guessed |
| Traceability | Which lots went into which batch, for recalls and claims |
| Customer trust | Evidence when a cafe says this week's coffee is different |
Manual vs software logging
A paper log with readings every 30 seconds works on a small roaster, but it is slow, easy to skip and hard to compare. Software that reads the roaster's probes draws the curves live, marks events, overlays a reference and stores everything against the batch. See the software buyer's guide.
Where Roastnet helps
Questions roasters ask
- What is a good development time ratio?
- There is no single right number; it depends on the coffee, the roaster and the style. Use DTR to keep batches of the same coffee consistent rather than as a target in itself.
- Can I log roasts without connecting my roaster?
- Yes, by hand. Connecting the roaster's probes to logging software records more data with less effort.
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Roast loss and shrinkage: where your kilos go
Every kilo of green coffee comes out of the roaster lighter. How much lighter depends on the coffee and the roast, and it changes your cost per kilo more than most price negotiations.
Run the roastery from one place
Green stock, roast plans, wholesale orders and the green coffee market in one platform, with a free roast-logging app for your machine.