Flavorings-Related Lung Disease: Alpha-Diketones

Green coffee beans in a burlap bag


Freshly roasted coffee beans in a large storage container.

Coffee Processing Facilities


Diacetyl (2,3-Butanedione) and 2,3-Pentanedione

Diacetyl and 2,3-pentanedione are volatile organic compounds known as alpha-diketones. These chemicals can be manufactured to make different flavorings that are sometimes added to food products (e.g., microwave popcorn, bakery mixes, flavored coffee) (Day et al. 2011; Kanwal et al. 2006; Bailey et al. 2015). Diacetyl and 2,3-pentanedione are also naturally produced and released during the coffee roasting process (Daglia et al. 2007). Grinding roasted coffee beans produces greater surface area for the off-gassing of these and other chemicals (Akiyama et al. 2003). Coffee roasting facilities package newly roasted coffee in bags fitted with a one-way valve or permeable bags to allow for off-gassing. Alternatively, newly roasted coffee is placed in tubs or containers and allowed to off-gas, which can contribute to worker exposures.

Page last reviewed: January 27, 2016