How to Choose the Right Coffee Roaster Capacity

Choosing a roaster size is the first real decision a coffee business makes, and it is easy to get wrong in both directions. Buy too small and you spend your evenings running batch after batch just to keep the shelves full. Buy too large and you tie up cash in a machine that never works near its comfortable range, which actually makes your coffee less consistent.

This guide walks through a simple, repeatable way to size a roaster. The whole method rests on one honest number: how much roasted coffee you really sell in a week.

Start with weekly demand, not a peak day

A single busy Saturday is a bad planning number because it pushes you toward a machine that sits idle the rest of the week. Weekly volume is far more honest. It smooths out the quiet Tuesdays and the busy weekends into something you can actually plan around.

Add up every kilogram of roasted coffee you move in a normal week. Include retail bags, wholesale orders, subscriptions, and whatever your own bar pulls through the grinder. That total, in kilograms per week, is the target your roaster has to hit comfortably.

Understand the working batch

A drum roaster does its best work at roughly 70 to 80 percent of its rated batch. A 10 kg machine is happiest roasting 7 to 8 kg. Overload it to a forced 10 kg and airflow and heat transfer suffer, which flattens your roast. Underload it to 2 kg and the beans rattle around with too much energy and not enough mass to carry it.

So when you read "10 kg roaster," plan your maths around an 8 kg working batch. That single habit prevents most sizing mistakes.

A simple capacity map

Use this as a starting point, then refine it with the cycle maths below.

• Under 50 kg per week: a 1.5 to 5 kg machine fits cafes and micro-roasteries that want hands-on control over every batch.
• 50 to 200 kg per week: a 10 to 15 kg roaster suits a growing specialty brand moving into steady wholesale.
• 200 kg per week and above: a 30 to 120 kg machine is built for near-continuous industrial production.

You can see the full line on our shop-type roasters page for cafes and the industrial roasters page for high-volume production.

Do the math on roast cycles

One roast cycle runs about 12 to 16 minutes. On top of that you need time to charge the drum, drop the beans, and cool them before the next batch. In real daily conditions, plan for three to four batches per hour, not the theoretical maximum.

Here is a worked example. A 10 kg roaster at an 8 kg working batch, run three times an hour, gives you roughly 24 kg per hour. Two focused hours covers a brand selling 150 kg a week with comfortable headroom for growth and the odd reroast. Run the same calculation with your own weekly number before you commit.

Leave room to grow, within reason

Buy for where you will realistically be in 18 to 24 months, not for a five-year dream. A machine one size above today's demand is sensible insurance. Three sizes above is a trap, because you end up roasting tiny batches in a big drum, which hurts consistency and wastes energy on every roast.

Plan the room, not just the machine

The roaster is only part of the decision. Larger drums need more floor space, stronger ventilation, and often a higher power or gas supply. Kafgar roasters are built to order for your local power, whether that is 110, 220 or 380V, so the electrical side is flexible. What you cannot skip is planning the room around airflow, an afterburner where local rules require one, and safe space to move green and roasted coffee.

A quick checklist before you buy

• Weekly roasted volume, written down honestly.
• Target working batch at 70 to 80 percent of rated capacity.
• Realistic batches per hour, including cooling time.
• Power and gas available in the room.
• Ventilation and emissions rules for your location.

If you share your weekly volume and the space you have, we can point you to the right size rather than the biggest one. Get in touch and we will work it out with you.