The Science of Scent...and smell. A book review (long).

Well, winter is coming so here is a nice piece to read and contemplate in front of the fire! At least up here in Alberta!!!

http://www.vinography.com/archives/2009 ... _same.html

Thanks for the link!

Just like someone with perfect pitch may love schlock, it's interesting to think an ultra-refined nose won't necessarily give you (what I would call) "good taste" - the guy thinks Concha y Toro is the world's greatest firm after Apple, Inc.!

Yes, thanks Bob. A bit of googling and I found this video of a short lecture given by Turin, which I thought others here might find interesting too.

http://www.ted.com/index.php/talks/luca ... scent.html

I am not convinced by his arguments that everyone smell things the same though. We know for a fact that sensitivities to different odours vary a lot, so if most real-life smells are combinations of individual odours the resultant "chords" must be different.

That is not a book review, it is a cheerleader's essay, and shows about the same amount of critical thought one would expect from a cheerleader stereotype.

For another take on this topic, see http://www.medicalnewstoday.com/articles/6713.php

Steve wrote;
I am not convinced by his arguments that everyone smell things the same though. We know for a fact that sensitivities to different odours vary a lot, so if most real-life smells are combinations of individual odours the resultant "chords" must be different.

Steve, Turin works in the perfume and fragrance industry, he is dealing with “isolated” aromatic compounds. Take vanilla extract out from your pantry and smell it, I think most of us will detect vanilla. If we take a small amount of “neutral” spirits and add small drops of vanilla extract eventually one will detect vanilla. For some of us we might need a higher concentration of vanilla extract than other. Total agree that the smell of wine could be the result of a single odorant or a combination of one or more odorants and how our mind interprets it.

BTW Bob thanks for posting the article.

Salute

I haven't read Luca Turin's book, but I have read a fairly extensive critique of that book, and the theories that are expounded therein, in the journal Science some years ago. I suppose that Mr. Yarrow would have to count me among that "scientific establishment" that dismisses Mr. Turin's ideas. One aspect of my critique: Mr. Yarrow uses the reported number of olfactory receptors (347) as an argument why there can't be a one molecule-one receptor correlation for smell, but that's been widely discredited for generations now. Instead, starting with just 347 receptors and assuming a binary (on/off) response, one can still posit 347! possible outputs, far more than is needed to characterize all of the smells that we are likely to be exposed to in a lifetime. What we know about those receptors is that they are fairly low affinity (as opposed to e.g. antibodies that have high affinity and strict specificity for one antigen) but broadly responsive, so that many different molecules may activate a given receptor, albeit to differing degrees (thereby expanding that initial figure of 347! to a far larger number). In fact, a friend at UT Austin has made a career out of developing a "molecular nose" that works in exactly the same way, using an array of low affinity receptors and applying sophisticated processing to their output.

Mark Lipton

I found this quite interesting:

The question of smoking and wine tasting got addressed at one point in the The Emperor of Scent. Burr recounts a conversation that Turin has with a researcher.

In it he mentions that half the perfumers he's met were smokers, and that there's a good reason that smoking would let people smell better, not worse.

"The carbon monoxide in the cigarettes totally blocks the enzyme cytochrome P450, the enzyme in the nose that breaks things down. Block this enzyme with smoke and you don't break down smell molecules, so they hang out in the nose longer than normal and you smell better.":

Hi Chef,
Very interesting indeed, I’m not so sure that “smokers” make better “smellers”. I believe that our olfactory receptors are capable of renewing themselves every 30 days.

Salute

I read "Emperor of Scent" and "Secret of Scent" and also got a book by Luca Turin about perfumes. And I found online sources for small samples of several of the perfumes that Turin found interesting, to try to understand why.

I enjoy his description of how the molecules work and I find his vibrational theory intriguing, including the part about zinc -- nobody else has explained why a zinc deficiency can ruin the sense of smell.

But -- I don't feel like digging around on this, but a year or 2 ago they gave the Nobel prize to someone who had been studying the sense of smell, and my neighbor is friends with that guy and says he thinks Turin is completely out to lunch. Which leaves me not knowing exactly what to think.

But it's fun to smell things and fun to think about the aromas...