Unlike a decreased sense of smell that occurs with a stuffy nose or sinusitis infection, people with COVID-19 may feel indifferent to simple smells. Some further suggest they have a hard time distinguishing wine from gasoline, spices, milk, and other related smells.
One reason why coffee in particular plays a prominent role in COVID sniff tests is its distinct taste and smell. Researchers have found scattered evidence showing exactly how coffee, with its strong, distinctive aroma, can act as an indicator of odor loss.
Given that anosmia is a common symptom in COVID cases, the global availability of coffee may make it easier to use, according to experts.
A Tufts University professor, James Schwob, a leading researcher who advocated the coffee test, said this could also be an early sign of when to call the doctor:
“One of the things that can be done fairly easily and objectively by someone at home would be to take some ground coffee and see how far you can hold it and still smell it.”
He also suggests that the same could be done with scents like alcohol, chocolate, or shampoo.