Tasting Guide™ 01 – Human Anatomy + Undeniable Science
When we consume coffee, magic happens. Flavor, as we experience it, isn’t isolated to our tongues. It isn’t just a list of notes on a bag. It's so much more than flavor notes. It’s not just “citrus,” “brown sugar,” or “bergamot.” It’s a conversation—between our mouth and our nose-almost as fast as the speed of sound, between aroma and structure, between chemistry and biology.
Starting at the point of contact: your mouth detects taste, but your nose defines flavor. Beginning with the former, taste—what your tongue does—picks up five basic things: sweet, sour, salty, bitter, and umami. That’s it. Everything else? Everything that makes coffee taste like a stone fruit orchard or a bar of dark chocolate? That’s the former-it's from the aromas. However, stone fruits are notoriously scentless or low in scent potency. This means one truth-our ability to properly identify and comprehend flavor in its totality comes from more than our taste buds-it's a synergistic system of our olfactory and gustatory systems working systematically in unison. When you sip coffee, the volatile compounds—microscopic aroma particles—move from the back of your mouth into your nasal cavity. This is called retronasal olfaction. Think of it as smelling the coffee from the inside out as you drink it. This process begins in the oral cavity, where heat and movement release volatile molecules. These compounds travel upward through the nasopharynx, the space connecting the mouth and the nasal passages. As you swallow, breathe, or slurp, these molecules pass through to the olfactory epithelium in the nasal cavity—a specialized tissue covered in hundreds of receptor neurons. The olfactory epithelium is home to roughly four hundred different types of olfactory receptors. Each receptor is tuned to a specific molecular feature. When volatile compounds hit these receptors, they send electrical signals via the olfactory nerve (cranial nerve I) to the olfactory bulb, and from there to the orbitofrontal cortex, where all sensory information is integrated. This happens almost as fast as the speed of sound or in half the time it takes the average human to blink. Heavy stuff.
Here’s where it gets important relating to our work: the orbitofrontal cortex is also where gustatory information from the tongue is sent. Your gustatory receptors, located on taste buds primarily on the tongue, send taste signals through the facial nerve, glossopharyngeal nerve, and vagus nerve. These converge in the nucleus of the solitary tract in the brainstem, are relayed through the thalamus, and then reach the gustatory cortex. Both olfactory and gustatory data converge in the orbitofrontal cortex, allowing the brain to synthesize these two distinct signals into what we call flavor. Akin to coding data points into a traceable image, this synthesis is involuntary. You could think of it as a hardwired setting in all humans: smell and taste share a stage, and they always perform together.
We often train novice enthusiasts and even remind ourselves occasionally of the importance of aerating coffee as we're cupping or sampling. Yet so many fail to truly understand why. That moment of aeration sends those volatile compounds rushing up into the olfactory system, triggering your brain’s flavor recognition engine. It’s also why holding your nose shuts down your ability to distinguish flavor-i.e. eating brussels sprouts. Without the nose, all you get is texture and basic tastes. The layered profile disappears. While the taste buds alone can still detect basic signals, your olfactory receptors are the ones doing the actual work of interpreting hundreds, even thousands, of aromatic compounds in real time. It's a massive neural keyboard, lighting up patterns that the brain interprets as “raspberry,” “molasses,” or “banana smoothie.”
Here's the most important part: you can’t separate this. You can’t not do this. The act of drinking, swallowing, breathing—it already pulls aroma into the nose by default. It’s a hard line default setting in all humans.
When I created the Tasting Guide™. It was to map experiencing any given coffee in a way we could briefly visualize the actual true encompassing of flavor-which is technically defined as more than just taste but "the blend of taste and smell sensations evoked by a substance in the mouth" (M+W). Tasting coffee is not linear or an assembly of mere notes—it’s dimensional, arranged, and responsive like a living constellation of stars in space.
Think about how temperature affects a cup. A hot coffee might announce itself with a rush of chocolate and malt. As it cools, the acidity sneaks forward—plum, then cranberry, then maybe a soft lime zest. These aren’t random changes. They’re shifts in which volatile compounds are activated, and which olfactory receptors light up. The flavor is evolving because your body is still listening. And not everyone hears the same thing. It's not uncommon to hear industry folk say "taste is subjective". Genetics play a massive role in how we perceive bitterness, sweetness, but especially aroma. Some people can pick up specific esters or phenolic compounds with incredible sensitivity while others may never register them. Your flavor map is uniquely yours—and it’s shaped by biology, memory, and experience.
This human anatomy and undeniable science is what makes coffee so alive and unique among other sensory experiences. It's why merely listing flavors on a bag fails to offer any given coffee's true nature. By instead visualizing what’s happening between your nose and your mouth, we can honoring the science and the true living nuance of what makes an Elida Estate Dark Room Geisha so complex or a Yunnan China lot so umami-forward. And the more we lean into that understanding, the more clearly we can communicate what a coffee actually feels like to taste.
Consider this: your body is already functioning harmoniously when you taste. It brings your senses together, funneling systems often over looked by other roasters and brewers, together into one experience. The Tasting Guide™ is here to help make that experience visible—more shareable—so that we can all partake in enjoying coffee a little more consciously, and with a little more wonder. The Guide is my gift to the industry I love. That's making being an enthusiast better for all.
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