# How does taste work?

**URL:** https://boards.straightdope.com/t/how-does-taste-work/1025858
**Category:** Factual Questions
**Created:** [December 19, 2025, 4:29pm UTC](https://boards.straightdope.com/t/how-does-taste-work/1025858 "2025-12-19T16:29:29Z")
**Posts on this page:** 1
**Showing post:** 16

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### Author: ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)
#### Post date: [December 27, 2025, 12:33pm UTC](https://boards.straightdope.com/t/how-does-taste-work/1025858/16 "2025-12-27T12:33:00Z")

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I posted this in a thread I had created about licorice in CS but it belongs here as well:

> **[Ammonium chloride tastes like nothing else. It may be the sixth basic taste](https://bigthink.com/health/ammonium-chloride-sixth-basic-taste/)**
>
> Ammonium chloride activates a specific sensor on sour taste receptor cells, making it eligible to be a primary taste.

Plus the following, related to licorice but not quite, is interesting about why taste gets so hard to use as a model of brain sensory function:

> **[Why Do Some People Hate The Taste Of Absinthe Science Behind The Anise Effect](https://www.alibaba.com/product-insights/why-do-some-people-hate-the-taste-of-absinthe-science-behind-the-anise-effect.html)**
>
> Explore the science behind why absinthe’s anise flavor divides drinkers—genetics, neurobiology, and cultural conditioning explain the polarized response.

> At the heart of absinthe’s signature profile lies _trans-anethole_, a phenylpropene molecule responsible for the sweet, warm, slightly medicinal aroma and flavor associated with aniseed. Unlike ethanol or sugar, which activate broad receptor families, trans-anethole binds selectively—and potently—to specific olfactory receptors (OR7D4 in humans) and bitter taste receptors (TAS2R subtypes). Its volatility means it’s perceived both retronasally (as aroma released during chewing or sipping) and orthonasally (as scent before ingestion), amplifying its sensory impact.
> 
> Crucially, trans-anethole isn’t just “strong”—it’s perceptually complex. At low concentrations, it reads as sweet and herbal. At higher doses—like those found in undiluted absinthe—it activates bitter pathways more intensely, while also stimulating trigeminal nerve endings, producing a mild cooling or numbing sensation on the tongue and palate. This multisensory layering explains why some describe absinthe as “medicinal,” “soapy,” or “chemical”: it’s not one note, but a chord of aroma, taste, and tactile feedback.
> 
> Yet concentration alone doesn’t explain the divide. Two people drinking the same glass of properly diluted absinthe—say, 3–5 parts water to 1 part spirit—can have diametrically opposed reactions. One finds it refreshing and layered; the other gags or pushes the glass away. That variance points squarely to biology—not brewing technique or serving ritual.
> 
> ## **The Genetics of Flavor Aversion: OR7D4 and the “Licorice Gene”**
> 
> In 2012, a landmark study published in _Nature Neuroscience_ identified a genetic variant in the olfactory receptor gene _OR7D4_ that directly correlates with perception of trans-anethole. Researchers discovered that individuals carrying two copies of the RT allele (rs6591536) perceive trans-anethole as intensely sweet and pleasant—often describing it as “anise,” “fennel,” or “candy-like.” Those with two copies of the WM allele, however, report it as overwhelmingly unpleasant—“urinous,” “sweaty,” or “rotten.” Heterozygotes (one of each) fall somewhere in between, often neutral or mildly negative.
> 
> This isn’t theoretical. The RT/WM polymorphism affects roughly 15–20% of Europeans, 30–40% of East Asians, and up to 55% of West Africans—distribution patterns that align closely with historical culinary use of aniseed and related spices. In populations where anise was traditionally used medicinally or culinarily (e.g., Mediterranean and Middle Eastern cuisines), the RT allele appears to have undergone positive selection—likely because detecting sweetness in plant compounds signaled safe, energy-rich food sources. Conversely, the WM variant may have conferred advantage in avoiding potentially toxic aromatic plants.

(Not quite related to licorice because while trans-anethole is often perceived as “licorice” actual licorice root has little to no trans-anethole in it, illustrating @Der_Trihs ’s point specific to olfaction about taste - different paths to similar perceptions.)

But yeah hard to have even a good shared vocabulary about tastes and smells when we may not be sharing the perceptual experiences?

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