Coffee Processing Facilities

coffee beans and a scoop

Coffee Roasting and Packaging Facilities


Coffee roasting and packaging facilities vary in size, number of employees and shifts, and the amount of coffee they roast, grind, and package. Some facilities are more automated than others, and some have attached or associated cafés. However, in general, coffee roasting and packaging facilities have many common processes.

  • Green coffee beans are delivered to the facility (often in jute or burlap bags) and stored or emptied into containers such as hoppers until roasted.
  • Before roasting, the green coffee beans are cleaned to remove stones, wood, and other impurities.
  • Many facilities blend coffee beans before roasting or after the roasting process. Blending involves mixing different types of coffee beans for a specific taste.
  • After roasting, the coffee beans are cooled. To make ground coffee, there is a grinding step. The roasted product is then allowed to off-gas.
  • Diacetyl, 2,3-pentanedione, other volatile organic compounds, and gases such as carbon monoxide and carbon dioxide are naturally produced during coffee roasting and released (off-gassed) during and after roasting. Grinding roasted coffee beans produces a greater surface area for off-gassing (sometimes called degassing) of these compounds.
  • After off-gassing, the roasted coffee is packaged. Newly roasted coffee is often packaged in permeable bags or in bags fitted with one-way valves to allow the coffee to off-gas after it is packaged.
  • Some facilities also flavor roasted ground or whole bean coffee before packaging.

Coffee Dust

  • Coffee dust is an organic dust and exposure to green and roasted coffee dust is known to cause respiratory symptoms and is a risk factor for occupational asthma [Karr et al. 1978; Zuskin et al. 1979, 1985, 1993; Thomas et al. 1991; Sakwari et al. 2013].
  • Green coffee dust is thought to be a more potent allergen than roasted coffee dust because roasting destroys some of the allergenic activity (ability to cause allergies) [Lehrer et al. 1978].
  • Castor beans, a potent allergen, may sometimes contaminate green coffee beans if the burlap bags or other containers used to transport the green coffee beans were previously used to transport castor beans [Figley and Rawling 1950; Oldenburg et al. 2009].


Carbon Monoxide and Carbon Dioxide

  • Carbon monoxide and carbon dioxide are colorless and odorless gases. You cannot see, smell, or taste them.
  • Carbon monoxide and carbon dioxide are released during and after roasting and grinding by off-gassing [Anderson et al. 2003; Hawley et al. 2017].



  • Diacetyl (2,3-butanedione) and 2,3-pentanedione (acetyl propionyl) belong to a group of volatile organic compounds known as alpha-diketones.
  • Exposure to alpha-diketones can occur during roasting, grinding, packaging, opening storage bins or containers with roasted coffee, and pouring and adding flavorings.
  • Diacetyl and 2,3-pentanedione are ingredients in flavorings used in some food products such as microwave popcorn, bakery mixes, and flavored coffee [Day et al. 2011; Kanwal et al. 2006; Bailey et al. 2015].
  • Diacetyl and 2,3-pentanedione also are naturally produced and released during the coffee roasting process [Daglia et al. 2007; Duling et al. 2016]. Grinding roasted coffee beans produces a greater surface area for off-gassing [Akiyama et al. 2003].

Mucous Membrane Symptoms

  • Some employees at coffee roasting and packaging facilities evaluated by the National Institute for Occupational Safety and Health (NIOSH) have reported that coffee dust causes or aggravates their eye, nose, or sinus symptoms.
  • People who become sensitized (develop an immune reaction) to coffee dust can subsequently have allergic-type symptoms (e.g., watery or itchy eyes or nose, stuffy nose, sneezing) to relatively low concentrations in the air. Others may experience irritant-type symptoms from exposure to coffee dust [Oldenburg et al. 2009].



Green and roasted coffee dust are known risk factors for occupational asthma [Figley and Rawling 1950; Karr et al. 1978; Zuskin et al. 1979, 1985; Thomas et al. 1991]. Coffee dust at low concentrations is known to cause respiratory symptoms [Zuskin et al. 1993; Sakwari et al. 2013].


Allergic Asthma

  • People with allergic asthma have airways that are extra sensitive to certain allergens. An allergen is a substance that causes the immune system to overreact in persons that are sensitive to the allergen. Allergens are also known as “allergy triggers.”
  • People who become sensitized to coffee dust can react to it after breathing in low concentrations in air. Breathing coffee dust can trigger inflammation and narrowing of allergen-sensitive airways in the lungs resulting in asthma symptoms such as coughing, shortness of breath, wheezing, or chest tightness.



  • In some people, asthma is aggravated by exposure to irritants such as fumes, gases, or dust.
  • Individuals who are not sensitive (not allergic) to coffee dust do not experience allergen-mediated inflammation or narrowing of the airways in the lungs; however, if they have asthma, inhaling coffee dust may irritate or aggravate (trigger) their asthma symptoms.

Information about work-related asthma can be found on the NIOSH work-related asthma webpage [NIOSH 2018] at


Carbon Monoxide and Carbon Dioxide Poisoning

  • During roasting, coffee beans generate carbon dioxide and carbon monoxide; grinding coffee increases the release of these gases [Anderson et al. 2003; Hawley et al. 2017].
  • Over exposure to carbon monoxide or carbon dioxide can cause headache, dizziness, fatigue, nausea, altered thinking, rapid breathing, impaired consciousness, coma, and death [Newton 2002; Nishimura et al. 2003; Langford 2005; CDC 2013a; Raffel and Thompson 2013; Rose et al. 2017; Permentier et al. 2017].
  • Over exposure to carbon monoxide or carbon dioxide from coffee can occur in situations when coffee is off-gassing in an improperly ventilated space or when entering a confined space such as a coffee holding tank or hopper [Newton 2010].


Obliterative Bronchiolitis (Lung Disease)

  • Obliterative bronchiolitis is a serious, often disabling, lung disease that involves scarring of the very small airways (i.e., bronchioles).
  • Symptoms of this disease may include cough, shortness of breath on exertion, or wheeze, that do not typically improve away from work [NIOSH 2012].
  • Occupational obliterative bronchiolitis has been identified in flavoring manufacturing workers and microwave popcorn workers who worked with flavoring chemicals or butter flavorings [Kreiss 2013; Kim et al. 2010; Kanwal et al. 2006].
  • This lung disease has also been identified in employees at a coffee roasting and packaging facility that produced unflavored and flavored coffee [CDC 2013b].
    • A NIOSH health hazard evaluation at that facility found diacetyl and 2,3-pentanedione concentrations in the air were elevated and identified three sources: 1) flavoring chemicals added to roasted coffee beans in the flavoring area; 2) grinding unflavored roasted coffee beans and packaging unflavored ground and whole bean roasted coffee in a distinct area of the facility; and 3) storing roasted coffee in hoppers, on a mezzanine above the grinding/packaging process to off-gas [Duling et al. 2016].
    • At the time of the health hazard evaluation, workers had excess shortness of breath and obstruction on spirometry, both consistent with undiagnosed lung disease. Respiratory illness was associated with exposure to diacetyl and 2,3-pentanedione and not limited to the flavoring areas [Bailey et al. 2015]. However, all workers who were diagnosed with obliterative bronchiolitis had worked in the flavoring area.
Page last reviewed: October 3, 2017