If there was ever a science experiment you’d want to participate in, it might be this one: sitting in a booth and inhaling the tangy, intense aromas of dark chocolates. But not just anyone gets to join this research. The people doing the sniffing were trained to detect subtle differences in scent, helping chemists uncover just which odor molecules are behind the distinctive smell of these rich treats.

In a paper published last week in the Journal of Agricultural and Food Chemistry, the researchers behind this endeavor reveal that dark chocolate’s aroma comes down to 25 molecules, in just the right concentrations — some of which you might find rather disgusting if you sniffed them on their own.

The sensory panel was part of a study on chocolates with cacao contents from 90 to 99 percent, which are growing more popular, said Michael Granvogl, a chemist at the University of Hohenheim in Germany who wrote the paper with Carolin Seyfried of the Technical University of Munich. While chocolate flavors — which, like all flavors, are a combination of taste and smell working together — have been studied for decades, this was one of the first times chocolate of such high cacao concentrations has come under the microscope. Or rather, perhaps, the sniff-o-scope.

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Fed through a battery of analytical machines, the chocolates yielded 77 compounds that could contribute to the chocolates’ aroma. Some were at levels too low to be detected by the human nose. But around 30 others made the sensory cut.