How Much Coffee Can a 20 kg Roaster Produce?

A 20 kg roaster does not produce 20 kg an hour. Here is how the number actually works out, and the three things that eat into it.

Start with the batch, not the hour

The HR-20KG takes 15–22 kg of green beans per batch, with a mid-point around 18.5 kg. A roast takes 12–15 minutes from charge to drop, and cooling takes another 2–5 minutes.

So one full cycle is roughly 15–20 minutes: charge, roast, drop, cool, refill. Call it three cycles an hour at best, and that is if somebody is standing there ready to load the next batch.

The daily figure

At 18.5 kg per batch and 15–20 minutes per cycle:

Twelve cycles is a realistic full day with one operator and a lunch break. Sixteen is two people and no interruptions.

What eats the output

• Cooling. Five minutes on a 20 kg batch is 25% of the cycle. A bigger cooling tray does not make the drum roast faster, it just stops the queue backing up.
• Cleaning between origins. Swapping from a dark roast to a light single origin costs a full cycle if you do it properly.
• Demand shape. If half your volume is one blend, you can run back-to-back. If you roast eight origins a week, you will spend more time on changeovers.
• Operator availability. A drum with nobody to load it is idle. This is why two people on one machine beats one person on two machines.

The nameplate number

Our figure for the HR-20KG is ~88 kg/h roasted. That is the continuous ceiling — the drum running non-stop at full batch. Plan on 60–70% of it for a real day: 50–60 kg/h in practice, which is 400–480 kg in an eight-hour shift.

If you need 400 kg of roasted coffee a day, the 20 kg is right at its limit. If you need 250 kg, it has headroom. If you need 150 kg, you are buying twice the machine you need and it will roast worse for it.