We’re all a fan of a good old fashioned home roast in this modern era of artisanal coffee beans. However, sometimes as you’re minding your own business, making a brew, your mother will send you a slightly fear-mongering email attachment about the hazards of roasting fumes. With a sigh (knowing that she means well), you read the article and against your better judgement, reflect that there might be something to it after all. So it begs the question: are coffee roasting fumes dangerous?
Although some of the gases released during the coffee roasting process are dangerous, home roasters are not in danger. The warnings about these gases are to be heeded on the industrial scale, and even a coffee shop or café will not operate on sufficient scale to face these health and safety issues either.
Unfortunately for those of us who don’t like to encourage our mothers’ fixation with clickbait articles, there have been studies showing that in coffee processing factories in Wisconsin high levels of two dangerous chemicals were found in the roasting bins. These gases naturally occur during the roasting and grinding processes, and the presence of diacetyl and 2,3-pentanedione in such high concentrations has been known to lead to lung disease in the form of bronchiolitis in studies involving animals. These compounds are deemed safe to ingest in small concentrations and are used because of their buttery taste, however inhaling them can prove fatal in some situations.
These gases are created during the roasting process and then released as the beans are ground up, and the levels of gas can build up while the beans sit in the storage bins, which poses risks for the factory workers. In some cases, the tested factories’ gas levels exceeded government regulation by up to four times the appropriate toxicity.
As a result, the US Centre for Disease Control and Prevention has suggested a new limit of 5 parts per billion units of the gas be imposed in factories, along with improved ventilation options to increase airflow and ensure a safer breathing environment for workers.
So, yes; the coffee roasting industry does have to negotiate these health hazards for the paramount safety of its workers. However, for those of you home roasting in a much smaller scale and better ventilated area, much to the relief of your mother, you’re safe. Phew!