You have two or three coffee roaster spec sheets in front of you and they do not line up: one quotes capacity in kilos, another in pounds an hour; one gives the burner in kW, another in BTU; one lists three electrical figures, another lists none. Here is what each line actually means for your business, the traps in comparing them, and the four lines to get confirmed in writing before you pay a deposit.
Rated Capacity: The Line Everyone Reads Wrong
"6 kg" on a spec sheet means the drum will hold 6 kg of green coffee. It does not mean you should roast 6 kg. Drums roast best at 60–80% of the rating — enough bean mass for the temperature probe to read properly, enough headroom to recover between batches. So a 6 kg drum is a 4–5 kg working machine, and a "5 kg" you see advertised may be a 5 kg drum you are expected to run flat out.
What to do: ask for the recommended daily batch, not the rated one, and compare machines on that. On our sheets the batch range is stated — the SD-6 Pro is rated 3.5–7 kg, and 5 kg is the number to plan around. The batch size guide explains why loading matters.
Output Per Hour: Check the Assumption Behind It
"18–28 kg/h" assumes a working batch and three to four cycles an hour. Divide the top figure by the batch you will actually run and you get the cycles-per-hour the maker assumed. If that is more than four, the number is optimistic. Then multiply by the hours you will roast — not eight, unless you have a full-time roaster.
Burner Rating: kW, kcal/h, BTU — and the Trap
Burners are quoted in kW, kcal/h or BTU/h depending on the country. Convert before you compare: 1 kW ≈ 860 kcal/h ≈ 3,412 BTU/h. Then look at burner per kilo of batch — a rough guide is that a drum needs enough input to bring a full batch to first crack in a sensible time without running the burner flat out.
The trap: input rating is not heat delivered to the beans. A well-built drum with good insulation and airflow does more with less; a thin drum with a huge burner wastes heat and scorches. And a burner that is too large for small batches cannot be turned down enough — you end up venting heat to keep control. So use burner rating to check the machine is not underpowered, not to rank machines.
Electrical: The Three Lines Your Electrician Needs
Every roaster has three electrical facts, and a sheet that gives only one is hiding two:
- Voltage and frequency — 220–240V/50Hz, 110–120V/60Hz, 380–400V three-phase.
- Phase — single or three.
- Connected load — the total watts. On a gas-heated drum this is small (motor, fans, controls — a few hundred watts); on an electric-heated machine it is the heating element, often 4 kW or far more.
If the sheet says "220V" and nothing else, ask. A DY-2 on gas draws 220 W; the same machine on electric heating draws 4,420 W. That is the difference between a wall socket and a dedicated circuit. The voltage guide covers what to check.
Airflow and Exhaust: The Line That Decides Your Building Work
Exhaust volume — quoted in m³/h or CFM — tells you the duct size, the fan the machine already has, and how much make-up air the room needs. It is the line that decides whether you need a 100 mm duct or a 200 mm one, and whether an afterburner or filter can be added later. If a sheet omits it, ask for it before you plan the room. The ventilation guide turns the number into a duct.
Dimensions and Weight: Measure the Door, Not the Room
Machine dimensions tell you it fits the room. What they do not tell you is whether it fits through the door, up the stairs, or onto the floor. An SD-3 weighs about 230 kg; an SD-12 class drum around 280 kg before beans; a 20 kg machine with loader well over half a tonne. Check the delivery route and the floor rating, and check the crate dimensions — usually larger than the machine — against your doorway.
Two Lines Most Sheets Leave Out: The Drum Wall and the Probe
A spec sheet tells you what the machine is rated to do. Two details that decide how it actually roasts are almost never on it, and both are worth a direct question.
The drum. Material, wall thickness and whether it is single- or double-walled decide how much heat the drum stores and how steadily it gives it back. A thick cast iron or double-walled drum holds its temperature between batches and lets you roast with the burner turned down; a thin single-wall steel drum in the same shaped body loses heat every time the door opens and pushes you to run the burner hard, which is where scorching and batch-to-batch drift come from. Two machines with the same "6 kg" and the same burner rating can behave completely differently for this reason alone. Ask for the drum material and wall thickness in writing; we state ours on the quote.
The probe. The bean temperature you will build every profile on is whatever the probe reads, and probes differ. A thin probe responds in seconds; a thick one lags, so the rate of rise it reports is smoothed and late. A K-type thermocouple covers the whole temperature range and is what most drums use for exhaust; a PT100 resistance probe is more linear, can be calibrated in the field and is what profile-control systems increasingly use on the bean pile. Neither is wrong, but you need to know which you have — and where it sits — before you compare your curves with anyone else's, and before you order a spare. Ask for probe type and diameter, and keep one spare of each; they drift before they fail.
"Automatic": What the Control Line Actually Covers
"Automatic" on a sheet can mean anything from a temperature display to a PLC that runs a saved profile. Ask three questions: can it save and repeat a profile; can you take over by hand mid-roast; does it log to Artisan or export data. Our SD Pro and YS machines answer yes to the first two on the PLC, and yes to the third when you ask for the Artisan interface at order (a priced option); a machine that only shows temperature is a manual roaster with a screen. The PLC guide explains what automation does and does not do.
The Four Lines to Get in Writing
Before the deposit, have the supplier confirm these four on the quote, not in a chat message:
- Rated batch range and recommended daily batch.
- Voltage, phase, frequency and connected load the machine will be built to.
- Gas type and supply pressure the burner will be jetted for.
- What is in the crate — cooling tray, cyclone, ducting, spares — and the delivery term.
A supplier who puts all four on the quote is telling you they build the machine. One who cannot is telling you something else. The buying guide covers the rest of the order.
Comparing Two Quotes: A Worked Example
Quote A: "6 kg roaster, 30 kg/h, 40,000 BTU, 220V, $X EXW". Quote B: "SD-6 Pro, 3.5–7 kg batch, 18–28 kg/h, LPG or NG, AC 220V/50Hz single phase, ships with cooling tray and cyclone, $Y FOB".
Quote A's 30 kg/h implies five 6 kg batches an hour at full rating — not achievable. Its burner is quoted without a per-kilo context. Its electrical line omits phase, frequency and load. And EXW means you add freight from the factory gate. Quote B gives you the working batch, a realistic output, the fuel options, the full electrical line, the inclusions and a delivery term. Even if $Y is higher than $X, B is the number you can plan around. For the record, our SD-6 Pro is USD 12,999 ex-works with the loader included, and the SD series page carries the full spec line for every model — the price guide lists every model with its inclusions.
Frequently Asked Questions
Can I ask for a spec sheet in my own units and language?
Yes — the sheet for every model can be issued with kW and kcal/h side by side, metric and imperial dimensions, and the manual in your language, which matters when the sheet goes to a gas engineer or an inspector who will not convert. Ask at quotation, and ask for the nameplate in the same units, because the inspector reads the plate, not the brochure.
What does "PLC" on a sheet guarantee, and what does it not?
That the machine has a programmable controller — nothing more. It does not tell you whether the controller saves and replays a profile, whether you can take over by hand mid-roast, or whether the curve can be exported. Ask those three as questions rather than reading the word; the PLC guide explains what each answer means for your roastery.
Why do two sheets for the "same" batch size show such different weights?
Because weight is where the drum wall and the frame show up. A 6 kg machine at 230 kg and another at 150 kg are not the same machine: the heavier one has a thicker or cast-iron drum, a heavier frame and more insulation, which is what holds heat between batches. Weight is the one line on a sheet that is hard to inflate, so read it with the drum material.
Should I trust a sheet that shows a roast time?
Only as a range. A roast time depends on the coffee, the batch size and the profile, so a sheet that says "12 minutes" is telling you about a test batch, not about yours. What a sheet can honestly state is the cycle time at the recommended batch with cooling — three to four batches an hour on most drums — and that is the number to size your day with.
What should the sheet say about spares and support?
Which parts are trade-standard and which are model-specific, what ships in the starter kit, and how parts travel — courier, days, who pays. A sheet that lists none of that is a sheet for the sale, not for the years after; the after-sales guide shows what the answers look like when a factory has them.
Final Thoughts
A coffee roaster spec sheet is easy to read once you know that capacity means the drum, output assumes a workflow, the burner needs context and the electrical line has three parts. Get the four lines in writing and two quotes become comparable. Send us the sheets you are looking at and we will read them with you. Talk to our engineers.
Get a Quote → WhatsApp +86 184 0771 4607Last updated: September 17, 2026
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