? Specific anosmia is a blind spot in your sense of smell. It means our sense of smell is functioning normally, but you are unable to detect a particular aroma compound. Much like colour blindness?where vision is intact but certain colours remain invisible?specific anosmia creates blind spots in your olfactory world.
? It?s in your genes. Whether or not you can smell a given compound is determined at birth and usually doesn?t change over time. If you were born without the ability to detect it, you?ll likely never gain it. It is highly likely you are anosmic to at least some of the key aroma compounds found in wine.
? The biology behind it. Our sense of smell relies on around 400 different types of receptors in the nose, each tuned to specific (fragments of) compounds. Specific anosmia occurs when one of these receptors is missing or not functioning properly?or when the brain fails to process its input.
? How do you find out your blind spot? You might already suspect you have specific anosmia to a certain wine aroma. To know for sure, you should try a wine sample “spiked” with an aroma compound. If the spiked sample seems identical to the untreated wine, it?s a clear sign of specific anosmia.
? The data. During our wine tasting courses, participants tried multiple wines with an aroma compound added. For extra certainty, the same compounds were also tested in water. When tasters reported ?no smell? in both wine and water, they logged their results via a form. The compounds were always presented at concentrations strong enough for most people to detect. Between early 2025 and the summer break, data was gathered from 90 to 160 individuals (depending on the compound tested). This dataset offers an insight at how common specific anosmias are, across different aroma compounds.
? A common question: ?If I can?t smell rotundone, does that mean a peppercorn grinder is odourless to me??
Not quite. Black pepper contains many aroma compounds besides rotundone?such as caryophyllene, pinene, and eugenol. While you may miss rotundone, you?ll still pick up the others. Together, they?ll still smell like black pepper. The same peppercorn grinder will smell slightly different to you, compared with someone who can pick up rotundone. The black pepper aroma in wine will be absent to you in (Syrah) wine, as the additional black pepper compounds (caryophyllene, etc) do not play a a role in wine.
Specific anosmia reminds us that tasting is deeply personal. What?s obvious to one taster might be completely invisible to another?not because of experience or skill, but because of biology.
Specific anosmia rates: white wine flavour compounds
| Compound | Descriptors | Origin | Specific anosmia |
| 4-MMP | Elderflower, passion fruit | Sauvignon Blanc | 2% |
| geraniol | Rose, citronella | Muscat | 16% |
| rose oxide | Lychee, honeysuckle | Gew?rztraminer | 9% |
| methyl anthranilate | Grape jelly, bubblegum | Fox grape | 3% |
| ethyl hexanoate | Apple skin, pineapple | Low temperature fermentation | 3% |
| diacetyl | Butter, yoghurt | Malolactic fermentation | 4% |
| vanillin | Vanilla, custard | Oak | 5% |
| eugenol | Cloves, nutmeg | Oak | 5% |
| TDN | Petrol, rubber | Riesling | 1% |
Specific anosmia rates: red wine flavour compounds
| Compound | Descriptors | Origin | Specific anosmia |
| 3-isobutyl-2-methoxypyrazine | Green bell pepper, tomato leaves | Cabernet Sauvignon | 1% |
| isoamyl acetate | Banana, bubblegum | Carbonic maceration | 2% |
| ?-ionone | Violet, dried chili pepper | Colour pigment degradation | 22% |
| eucalyptol | Eucalyptus, bay leaf | Eucalyptus trees | 3% |
| rotundone | Black pepper, sandalwood | Syrah | 20% |
| whisky lactone | Coconut, dill | Oak – American | 6% |
| 2,3,5-trimethylpyrazine | Chocolate, damp | Oak | 3% |
| 4-EG | Leather, fig | Bottle ageing/Brett | 2% |
Specific anosmia rates: wine faults
| Compound | Descriptors | Fault | Specific anosmia |
| TCA | Wet cardboard, damp cellar | Cork taint | 1% |
| acetaldehyde | Bruised apple, beansprouts | Oxidation | 2% |
| sotolon | Brown sugar, fennel | Oxidation | 3% |
| methyl mercaptan | Camembert, rubbish bin | Reduction | 8% |
| guaiacol | Smoked fish, smoked meat | Smoke taint | 4% |
| 4-EP | Band-aid, blue cheese | Brettanomyces | 3% |
| isovaleric acid | Vomit, sweaty socks | Brettanomyces | 1% |
| acetic acid | Vinegar, cider | Volatile acidity | 1% |
| ethyl acetate | Nail varnish remover, glue | Volatile acidity | 3% |
| 3-isopropyl-2-methoxypyrazine | Potato skin, asparagus | Ladybird taint | 4% |
