Most of what we call "taste" is really several senses working together, and once you know which is doing what, you cook differently.
First, forget the tongue map
You may have been taught that the tip of the tongue tastes sweet, the sides taste sour and salty, and the back tastes bitter. It's one of the most widely taught myths in school biology.
It started with a real 1901 German study by David Hänig, which found only small differences in sensitivity in different parts of the tongue. In 1942 the psychologist Edwin Boring replotted Hänig's data in a book, and later readers misread the graph as showing that each zone tastes only one thing. The "map" was born. In 1974 the researcher Virginia Collings confirmed what you can check yourself with a pinch of salt on the tip of your tongue: every taste can be detected on every part of the tongue that has taste buds.
The tongue map is a misreading of a graph, repeated in textbooks for decades.
Taste: five basics (and maybe more)
What the tongue really does is narrow and precise. Taste buds, of which a typical tongue has a few thousand, detect a short list of basic tastes:
| Taste | What it signals | Where you meet it |
|---|---|---|
| Sweet | Sugars, energy | Fruit, honey, caramelized onions |
| Salty | Sodium and minerals | Salt, soy sauce, cheese |
| Sour | Acids | Lemon, vinegar, yogurt, ferments |
| Bitter | Possible toxins | Coffee, dark greens, beer |
| Umami | Glutamate: savory, "meaty" | Parmesan, tomatoes, mushrooms, soy sauce, broth |
Umami is the newest member. The Japanese chemist Kikunae Ikeda identified it in 1908, when he worked out that glutamate was behind the deep savoriness of kombu seaweed broth. A year later he co-founded the company that sold the first umami seasoning, MSG. Western science was slow to accept umami as a basic taste; the term was adopted at an international scientific symposium in 1985, and specific umami receptors were later identified on the tongue.
The list may not be finished. In 2015 a Purdue team including the nutrition scientist Richard Mattes argued that fatty acids form their own distinct taste. That idea is still debated.
Taste receptor cells don't last long; a typical taste bud lives about ten days before being replaced.
Smell: the sense that does the heavy lifting
Here's what the jelly bean showed you. Smell reaches you by two routes:
- Orthonasal smell — sniffing through your nostrils, like smelling bread from across the room.
- Retronasal smell — aromas rising from your mouth up the back of your throat into your nose as you chew and swallow.
The psychologist Paul Rozin argued in 1982 that these work almost like two different senses: people who learned to recognize odors by sniffing were much worse at naming the same odors delivered to the back of the mouth. It's the retronasal route that turns "sweet" into "strawberry." That's why food tastes of almost nothing when you have a blocked nose.
You'll often hear that "80% of flavor is smell." It's a nice line, but there's no solid study behind the exact number. The honest version is: smell supplies most of the specific flavors you can name, and taste supplies the basic framework.
How many smells can we tell apart? A 2014 study in Science claimed humans can distinguish at least a trillion different odor mixtures. In 2015, two researchers, Richard Gerkin and Jason Castro, showed the calculation was fragile and that the data didn't actually support the claim. The real number is unknown, but it's clearly very large.
Why your friend hates cilantro
Not everyone's senses are tuned the same way.
Cilantro (coriander leaf) tastes fresh and citrusy to most people and like soap to some. A 2012 genetic survey of nearly 30,000 people linked the soapy experience in part to a variant near a smell-receptor gene, OR6A2, which is sensitive to the aldehyde compounds in the herb. How common the dislike is varies: one study found it in about 21% of East Asian participants and 17% of Europeans, but only 3–7% of South Asian, Hispanic and Middle Eastern participants, groups whose cuisines use cilantro heavily. Genes are part of the story; familiarity seems to matter too.
Supertasters. The psychologist Linda Bartoshuk coined the term for people who find bitter compounds, and tastes in general, unusually intense. Estimates often split people into roughly a quarter "non-tasters," half "medium" and a quarter "supertasters," but those numbers vary between studies and should be taken loosely. If someone at your table finds raw broccoli or black coffee genuinely unbearable, they may not be fussy; they may be wired differently.
What this means for your cooking
- Season for the tongue, flavor for the nose. Salt, acid and sweetness balance a dish (see Salt, Fat, Acid, Heat). Aroma, from herbs, spices, browning and fresh zest, gives it identity.
- Add aromatics late as well as early. Long cooking builds depth, but a handful of fresh herbs or a grating of citrus zest at the end puts back the bright smells that heat drives off.
- Use umami when something tastes "thin." A spoon of soy sauce, a rind of parmesan or some tomato paste can add depth to a dish that's well salted but still flat.
- Smell as you cook. Your nose often tells you that spices are toasted, garlic is about to burn or a sauce is ready, before your eyes do.
The takeaway
The tongue map is a myth: every part of the tongue can detect every basic taste. The tongue handles a short list (sweet, salty, sour, bitter and umami, with fat still debated), while smell, especially retronasal smell from inside your mouth, supplies most of the specific flavors you recognize. Genes make some people taste the world differently, from soapy cilantro to intensely bitter greens. Cook with both senses in mind: balance with taste, and build identity with aroma.
Try this: do the jelly-bean test with whatever you're eating tonight. Take one bite with your nose pinched and one without, and notice what disappears. Then add a last-minute squeeze of citrus or handful of fresh herbs to the dish and taste it again.
Sources & Further Reading
Sources
- Tongue map origin (Hänig 1901; Boring 1942) and refutation (Collings 1974): Wikipedia, Tongue map, and its cited sources, including Spence (2022), Current Research in Food Science.
- Umami: Ikeda (1908), Ajinomoto (1909), adoption of the term in 1985 and the umami receptor: Wikipedia, Umami, and sources.
- Taste bud count (about 2,000–8,000) and turnover (about 10 days): Wikipedia, Taste bud, and sources.
- Fat as a possible sixth taste (2015, Purdue, Mattes): Wikipedia, Taste and Oleogustus, and sources; still debated.
- Retronasal smell: Paul Rozin (1982) on smell as a "dual sense"; Gordon Shepherd, Neurogastronomy (2012); as summarized in Wikipedia's Retronasal smell entry.
- Trillion-odor claim: Bushdid et al., Science (2014); rebuttal: Gerkin & Castro, "The number of olfactory stimuli that humans can discriminate is still unknown," eLife (2015).
- Cilantro: a 2012 genetic survey of nearly 30,000 people linking a variant near OR6A2; prevalence by ancestry from Mauer & El-Sohemy (2012), as summarized in Wikipedia's Coriander entry.
- Supertasters: Linda Bartoshuk; prevalence estimates vary (Wikipedia, Supertaster, flagged as needing better sources).
Go deeper
- 📘 Neurogastronomy — Gordon M. Shepherd (how the brain builds flavor from taste and smell)
- 🌐 eLife — Gerkin & Castro on the trillion-smells claim
- 🌐 Related in this library: Salt, Fat, Acid, Heat
For Your Vocabulary
Basic Tastes (the short list the tongue detects: sweet, salty, sour, bitter, umami) · Umami (the savory taste of glutamate, named by Kikunae Ikeda in 1908) · Retronasal Smell (aroma reaching the nose from inside the mouth while eating; the source of most flavor) · Orthonasal Smell (smelling by sniffing through the nostrils) · Flavor (the combined experience of taste, smell, texture and temperature) · Supertaster (a person who experiences tastes, especially bitterness, unusually intensely) · Aldehydes (aroma compounds in cilantro that some people perceive as soapy) · Glutamate (the amino acid behind umami)