Why do some coffees taste like wine or whiskey?

The perception of wine or whiskey notes in coffee is not a byproduct of aging or additives, but a deliberate manipulation of the coffee cherry’s metabolic environment post-harvest. While traditional processing focuses on mucilage removal, modern producers are increasingly treating fermentation as a precise biochemical tool. By utilizing closed bioreactors or sealed tanks to create anaerobic (oxygen-free) environments, producers encourage specific microbial populations—often including lactic acid bacteria and yeasts—to thrive. These microorganisms metabolize the sugars and pectin in the coffee fruit, generating a suite of volatile organic compounds, including esters and alcohols, that penetrate the parchment and influence the bean's internal chemistry. A common misconception is that these flavors are merely 'surface-level' or defects; in reality, when managed with scientific rigor, these processes enhance the cup's acidity, body, and aromatic complexity. For the producer, this is a high-stakes balancing act: extending fermentation time can unlock profound notes of red wine, rum, or dark fruit, but if the microbial activity is not strictly monitored, it can quickly veer into astringency or acetic off-flavors. This shift represents a move away from 'commodity' processing toward a model where the farmer acts as a fermentation scientist, using controlled variables to curate specific sensory outcomes that command higher market premiums.