The conventional approach appears to be - buy a roaster and endure its limitations. Most conventional roaster owners spend more time developing marketing spin than improving their coffee roaster. The deficiencies i.e. emissions are already the focus of some legislative bodies which require permits for roasters in their jurisdictions. Oil burning engines, showing that blue smoke, are rarely seen on the road today yet many owners are complacent about roasting without pollution controls.
The roaster owners who are concerned that large plumes of smoke coming from their chimney are bad for their community image have purchased large gas fired after-burners that burn approximately three times more gas than the roaster itself. Imagine if automobile pollution controls involved using three times more gasoline than the engine.
Rather than maintain the polluting status quo which may or may not have visible smoke, NXT Roasters Inc., have developed an alternative (branded the Roastaire in Canada) approach that uses the smoke generated as a source of roasting heat rather than expend large amounts of additional energy to thermally neutralize the smoke. Both 15 Kg/hour concepts thermally treat the pollutants but one system uses a 400,000 to 700,000 BTU after-burner to accomplish the task.
The first picture is of the main air passageway of a Roastaire after five years of full time roasting. This revealing photo demonstrates the reason for their motto of "Clean Air Roasting". This illustrates how efficient and effective the air is scrubbed clean as it is re-circulated during the roasting process. This closed loop roasting process means that the air only has to be heated 20° to 40°C to return it to the roasting temperature. Compare that to a single pass air supply that is continually heated from ambient temperature then sent to the chimney. In "Espresso Coffee" R. Eggers writes the typical gas temperature of a drum roaster is 400° - 550°C. What a wasteful process.
In comparison,
one drum roasters Maintenance Manual draws attention to the chimney, "Even if residue build-ups do not exceed 1/8 inch (.3 cm) per year, clean system annually ". The quotation is not properly cited nor acknowledged but I will do so if the manufacturer requests it.They also have this picture of a drum roaster fan as a warning about the residue that coats some of their components. Roast Magazine had the following quotation "It's not IF you're going to have a roaster fire, but WHEN." Which roaster do you think requires the most maintenance? Which type of roaster do you think was responsible for nearly 1,800 chimney fires in the USA in 2010?
Which roaster do you think roasted hundreds of pounds of green beans inside the exhibition hall of the last four annual
Canadian Coffee & Tea Shows?
