Desensitization, adaptation and cross-adaptation - perils for wine tasting

One of the pitfalls in tasting is the way that our sensory systems are quite malleable. Take vision, for example. If you are out in the sunlight and then walk into a slightly darkened room, it takes a while before you can see anything. Your visual system adapts to the ambient conditions. We take this for granted.

Now if you have been wearing coloured sunglasses, your visual system will have adapted to their tint, and when you take them off, everything will have a strange colour cast that takes a few minutes to lose. This is one piece of evident that argues for the subjectivity of colour perception.
A similar sort of adaptation takes place with the sense of smell. It’s called desensitization.

We can enter a room or a home and find it incredibly smelly, but then after a while we get used to that smell. This is an important ability: the strong smell would otherwise override more subtle smells. It’s not a complete adaptation, because some smells are powerful enough that they are merely dampened down. But it can explain why some people can have terrible body odour problems but not seem to notice it themselves – if they did, you’d assume they might do something about it.

Aside from desensitization, there is also a phenomenon called cross adaptation. This is when the process of adaptation to smell X causes some adaptation to smell Y. Now desensitization is problematic for wine tasting, but cross adaptation may be even more dangerous.
If there is a recurring smell during the tasting process, then you will become desensitized to that smell. It might be a wine component, or it might be an environmental smell, such as coffee or paint fumes or cooking smells. If the smell is a wine aroma, this will change your perception of the wine without being aware of it. A lengthy flight of the same kind of wine could be risky in this regard.

Cross-adaptation is even more of an issue because a smell unrelated to the wines you are tasting might change the perception of a particular wine component and thus the perception of the wine. The big problem with this is the sheer unpredictability of the process.

Surprisingly often I have sat with people and drunk a bottle over an evening, and then found ourselves commenting on how much the wine changed in the glass or decanter. The assumption here is that it is the wine that has changed; this may not be the case – it could be us.

Can anything be done? If we are judging wines it is sensible to work in short flights. The tasting order among judges needs to be mixed up (ideally randomised, but having one judge work backwards could help and is simpler to administer). Switching from a flight of wines of one type to a different type makes sense, and keeping this alternation going through the day would be wise. Any noticeable aromas in the room should be eliminated. And judges should have regular breaks.

6 comments to Desensitization, adaptation and cross-adaptation – perils for wine tasting

  • Thanks for raising this interesting subject, about which I’ve been thinking recently myself. If the point is just to prevent cross-adaptation effects of each stimulus on the others, then the standard psychophysical procedure would be to return to a state of neutral adaptation between exposures. One question here is what should count as bringing about neutral adaptation for wine tasting — I’ve heard various suggestions including tap water, saltines, and artificial saliva (yuck). Another question is whether it matters to bring subjects to *neutral* adaptation, as opposed to simply a consistent standard: consistent adaptation to (say) a standardized lemon juice would plausibly swamp the effects of cross-adaptation (for some kinds of stimuli, at any rate) just as well as the purportedly more neutral standards such as tap water. I’d also be interested to compare randomized tasting order without any neutral adaptation, on the one hand, against neutral adaptation but without randomizing the presentation order. It’s not obvious that both would block the same kinds of cross-adaptations, to the same extent. I suspect there are a lot of interesting issues lurking in this neck of the woods….

  • Greg

    Very thought provoking post. I often wonder as well whether the wine or the taster changes over time. Do we become desensitized to strong flavor components? Perhaps that explains why certain professional critics and collectors who engage in ‘competitive tastings’ don’t experience the high alcohol, overwhelming oak and monolithic fruit flavors in internationally styled wines the same way glass-by-glass wine drinkers do.

    Also, how does inebriation affect perception?

    In any case, I believe that there is a major difference between drinking a glass of wine and tasting 1 oz. pours in succession. These different approaches introduce their own unique biases and will not necessarily select for the same wines in terms of consumer preference. If as a wine drinker you are buying wines to drink based on critics judging in a ‘competitive tasting’ format, then you are not getting the right information. That is information for collectors who drink taste by taste, not wine drinkers who drink glass by glass.

  • Alex lake

    Perhaps this partly explains why most competition results are not particularly useful?

  • Mike Hadwin

    In some top end perfume stores I have seen jars of coffee beans used to apparently “reset” your nose between perfumes. Not sure if this has any basis or would even be useful when nosing wine.

  • Nicolas R.

    I understand the desire (and ultimately profession) of tasting wine in order to work them out in the finest of details so that they can be assessed with depth and compared against their peers with accuracy and precision (am I getting this purpose right?). But ultimately, wine is meant to be tasted AND drunk by women and men who have an extremely varying degree of tasting experience and knowledge in environments where you never quite the clinical smell-free environment. There are even many wine writers, tasters, sommeliers, bloggers…and winemakers who discard describing wine in absolute smell terms but instead use a more abstract language that may be more difficult for some but easier for others to understand since it is maybe a bit more evocative of the actual physical experience of drinking wine…and this accepts the imperfections of the tasting environment.

    So what I’m trying to get at is, knowing that this “trickery” played out by our own tasting apparel exists is good but why is it so important to counteract it as much as possible? What is the ultimate added value and improved outcome for readers and wine amateurs around the world in ensuring that professional tasting environments and settings prevent these phenomenons from occuring since ultimately the drinker amateur will not have these anyway and therefore will not be able to connect fully with what the tasters and writers have to say about the wine ?

  • Hi Jamie – new to the blog, been poking about. Great stuff you’re doing here! I’ve found that yes, short flights work, as does running the table of wines quickly, taking down initial impressions and then continuing to revisit. Although it is one of those things where you can always second guess, “how do you know what you think you know” sort of a thing. My head hurts now, I need a glass of wine ;-) sonomaist.com

Leave a Reply

 

 

 

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

*