Via Inverse, a story from this week's Fall ACS meeting:
Coffee can typically be tweaked with sugar or dairy to make even the worst brews somewhat palatable, but the Specialty Coffee Association (SCA) specifically describes the mouthfeel, or body, of coffee as the “tactile feeling” of the drink your mouth without these amendments. This is the physical sensation that accompanies a sip — and the realization that your brew is thick and velvety, thin and delicate, or something in between.
On Tuesday at the American Chemical Society fall meeting, scientists revealed the chemical compounds responsible for causing the phenomenon.
They found small molecules, rather than sugars and lipids as believed, influence mouthfeel. The study team used a combination of chemical analysis and expert palettes to zero in on what compounds are responsible. Just as wine lovers can attribute certain features to specific compounds, now coffee fans can do the same.
Sounds like they used both tasters and prep-scale chromatography to separate out compounds that might be associated with mouthfeel:
From this process, the team was able to pinpoint several different compounds responsible for telltale tactile sensations, including that compounds formed during roasting are responsible for the astringent component of coffee’s body.
These melanoidin compounds are caused by the Maillard reaction, which is the same reaction responsible for the caramelized-like exterior of a good steak.
I'll be honest - coffee is just a caffeine delivery device to me, and it's rare that I actually taste what I am drinking. But I'll bet I notice mouthfeel more than taste!