Does every coffee roaster need an afterburner?

No. Many small roasteries operate without one. Whether you need one depends on your site and neighbours; ask your local environmental health team.

Is a catalytic converter as good as an afterburner?

Both can be effective when sized and maintained correctly. Catalytic units usually run at lower temperatures and use less fuel; thermal units are more tolerant of heavy loads.

Afterburners, catalytic units and roaster emissions

Smoke and odor are the most common reason a roastery gets into trouble with neighbours. What afterburners and catalytic units do, what they cost to run, and how to decide whether you need one.

7 min read Updated October 9, 2026

Roasting releases smoke, volatile organic compounds and odor, more so as roasts get darker and batches larger. Near homes, those emissions can become a statutory nuisance, which the local authority must investigate and can require you to stop. An abatement unit removes most visible smoke and much of the odor before the exhaust leaves the flue.

The options

Unit	How it works	Points to consider
Thermal afterburner (thermal oxidiser)	Heats the exhaust to a high temperature so smoke and odorous compounds burn off	Effective; uses significant fuel; sized to the roaster's exhaust volume
Catalytic unit	A catalyst oxidises the compounds at a lower temperature than a thermal afterburner	Lower fuel use; catalyst needs inspection and eventual replacement; sensitive to oils and chaff
Integrated recirculation	Some roasters burn off smoke inside the roasting system	Built into certain designs; check what the maker guarantees
Higher flue and better dispersion	Releases exhaust higher so it disperses before reaching neighbours	Helps but does not remove smoke; may need planning permission

Do you need one?

There is no single national threshold that says a roaster of a given size must have an afterburner. The practical answer depends on your batch size, roast degree, hours of roasting, flue height and how close the nearest homes, offices and air intakes are. Ask your local authority's environmental health team before you buy, describe the roaster and the site, and get their expectation in writing. A planning permission may include a condition about abatement.

Running cost

A thermal afterburner can use as much energy as the roaster or more, because it must heat the whole exhaust stream. Ask the maker for consumption figures at your batch size and include them in your cost per kilo. Catalytic units usually use less fuel, but budget for catalyst inspection and replacement.

Keeping complaints away

Good practice

Talk to neighbours before you start and give them a phone number
Roast at sensible hours, especially dark roasts
Keep the abatement unit at working temperature before the first batch and until the last has finished
Clean chaff collectors and ducts on schedule; dirty systems smoke more and are a fire risk
Log abatement temperatures with your batch logs, so you can show it was working
Respond quickly and politely to any complaint

Fire risk

Chaff and oily deposits in ducting are the source of most roastery fires. An afterburner does not reduce that risk; maintenance does. See the maintenance schedule.

Where Roastnet helps

Questions roasters ask

Does every coffee roaster need an afterburner?: No. Many small roasteries operate without one. Whether you need one depends on your site and neighbours; ask your local environmental health team.
Is a catalytic converter as good as an afterburner?: Both can be effective when sized and maintained correctly. Catalytic units usually run at lower temperatures and use less fuel; thermal units are more tolerant of heavy loads.

Official sources

Rules change. These sources were checked on October 9, 2026; always confirm the current position with the body that publishes them before you act.