How does retronasal olfaction work in tea tasting?
Written by Dian VAULTIER·
In Brief
- Expert tea tasting is not limited to the taste perceived by the tongue, whose receptors do no more than identify the basic tastes.
- When the tea is in the mouth, the heat and mechanical agitation of tasting release volatile compounds that travel up through the retronasal passage, connecting the back of the throat to the…
- The expertise of the HOLLIN sommelier: how retronasal olfaction works in tea tasting, explained by a purist Tea House with no added flavorings, based in Sartrouville (Île-de-France) and shipping its grand cru teas worldwide.
Expert tasting of tea is not limited to the taste perceived by the tongue, whose receptors do no more than identify the basic tastes. The essence of aromatic complexity is revealed through retronasal olfaction, a sensory mechanism that carries volatile compounds from the oral cavity to the olfactory epithelium via the back of the throat. Mastering this mechanism radically transforms the aromatic reading of a tea.
The path of aromatic molecules
When the tea is in the mouth, the heat and mechanical agitation of tasting release volatile compounds that travel up through the retronasal passage, connecting the back of the throat to the nasal cavity, until they reach the olfactory receptors located at the top of the nasal passages.
This path differs fundamentally from the direct olfaction practised by smelling the tea before drinking it, known as orthonasal olfaction. The two pathways often perceive different nuances in the same tea, with retronasal olfaction generally revealing deeper, more persistent notes.
The mouth-slurping technique
Professional tasters deliberately draw in the liquid noisily, mixing it with air, to vaporize more volatile compounds and artificially intensify retronasal perception. This technique, known as slurping in both tea and coffee tasting, allows for a more refined analysis of the aromatic profile.
After this inhalation, a brief pause in the mouth followed by a slow exhalation through the nose maximizes the transfer of volatile molecules to the olfactory receptors, revealing base notes often absent from the initial orthonasal impression.
What retronasal olfaction reveals about the quality of a tea
Length on the palate, a central criterion in evaluating a grand cru, depends directly on the persistence of volatile compounds perceived through retronasal olfaction after swallowing. A poor-quality tea often has a short, indistinct retronasal signature, while a grand cru develops complex notes that evolve over several dozen seconds.
This technique also makes it possible to detect certain flaws, such as musty or stale notes, sometimes masked when simply smelling the dry or infused tea through orthonasal olfaction.
The purist selection of HOLLIN
At the counter HOLLIN of Taste, 22 avenue de la République, 78500 Sartrouville, open Monday to Saturday from 10h to 20h, our tea masters will gladly introduce you to this tasting technique during guided sessions, allowing you to fully appreciate the complexity of our finest teas.
This rigorous sensory approach is an integral part of our teaching, shared with every client curious to deepen their daily tea-tasting practice.
Frequently Asked Questions (FAQ)
- Why do some tea tasters draw in the liquid noisily?
- This inhalation, known as slurping, mixes the tea with air to vaporize more volatile compounds and intensify retronasal perception. This professional technique allows for a more precise analysis of the aromatic profile, particularly the tea's length on the palate.
- What is the difference between orthonasal olfaction and retronasal olfaction?
- Orthonasal olfaction refers to smelling directly through the nose before drinking, while retronasal olfaction perceives the volatile compounds that travel up from the mouth to the nasal passages after swallowing. These two pathways often reveal distinct aromatic nuances in the same tea.
- Can retronasal olfaction identify a lower-quality tea?
- Yes, a short, indistinct retronasal signature or one marked by musty and stale notes often indicates a poor-quality or improperly stored tea. A grand cru, by contrast, is distinguished by complex, persistent notes after swallowing.