Aroma: There's smell and then there's aroma!

It's tea time ladies, grab yer mugs! Drink it fast or sip it slow. About glasses, how ta crook yer pinkie, nosing and tasting techniques and equipment. May your cup - and your women - be bottomless!
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Capn Jimbo
Rum Evangelisti and Compleat Idiot
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Aroma: There's smell and then there's aroma!

Post by Capn Jimbo »

Your nose knows...

Perhaps one of the most joyous experiences of life is aroma. For some reason aroma is tied to our memories and expectations, both. This was put most eloquently by Helen Keller:
"Smell is a potent wizard that transports us across thousands of miles and all the years we have lived. The odors of fruits waft me to my southern home, to my childhood frolics in the peach orchard. Other odors, instantaneous and fleeting, cause my heart to dilate joyously or contract with remembered grief. Even as I think of smells, my nose is full of scents that start to awake sweet memories of summers gone and ripening fields far away."
Olfaction - smells and aromas - seems to be a sense that is closely linked to our limbic brain which is tied to both emotion and memory. For example, Sue Sea has experienced rums that - out of nowhere - have caused her to tear up and remember her grandfather and his leather table. But as always, I digress.

The many aromas of both rum and whiskey (brown spirits) are directly related to both esters and acids. Both of these, especially with barrel aging, lead to ever more complexity. Except for the Jamaican style most rums contain an average of perhaps 50 or 60 esters. What made and makes Jamaican rums prized is their process of using combinations of molasses, skimmings, dunder and cane juice - even pieces of cane - in ther fermentations. The result:

Up to 1700 esters in four ester-based categories.

Yet one wonders: are all of those esters important? Are they detectable and can they be distinguished from one another. In a definitive word: maybe!

German scientists recently published a study of bourbon to explore these questions. They found that of 300 components of whisky (including esters) they wondered which, if any components might be "key components" responsible for the "fruity, smoky, vanilla and other harmonics of whiskey".

In their study Peter Schieberle and Luigi Poisson focused on just 40 compounds (13 newly discovered) that they believe are most responsible for the pleasant and classic aromas of bourbon ("...a signature mixture of scents, including fruity, earthy and cooked apple").

And what did they conclude? Stay tuned... (don't you just hate me?)


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Note: The answer may be found in ACS' (American Chemical Society) bi-weekly Journal of Agricultural and Food Chemistry, issue of July 23, 2008.
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Capn Jimbo
Rum Evangelisti and Compleat Idiot
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Joined: Mon Dec 11, 2006 3:53 pm
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Don't give me those sad eyes...

Post by Capn Jimbo »

Alrighty then...

I'm fully aware that most of us simply skim around the net, chasing shiny baubles which we gleefully pick up, briefly examine and then toss away, to chase yet another factoid.

Cotton candy surfing.

But for those, er maybe you, who care - here's a very brief summary of their comprehensive study:
"Application of the aroma extract dilution analysis (AEDA) on the volatile fraction carefully isolated from an American Bourbon whisky revealed 45 odor-active areas in the flavor dilution (FD) factor range of 32−4096 among which (E)-β-damascenone and δ-nonalactone showed the highest FD factors of 4096 and 2048, respectively.

With FD factors of 1024, (3S,4S)-cis-whiskylactone, γ-decalactone, 4-allyl-2-methoxyphenol (eugenol), and 4-hydroxy-3-methoxy-benzaldehyde (vanillin) additionally contributed to the overall vanilla-like, fruity, and smoky aroma note of the spirit.

Application of GC-Olfactometry on the headspace above the whisky revealed 23 aroma-active odorants among which 3-methylbutanal, ethanol, and 2-methylbutanal were identified as additional important aroma compounds."
Got it? I read Greek, so let me interpret. Of 45 "odor active areas" of interest, they found 6 which seemed to be most important. Of 23 more active areas they studied, they found 2 more with particular signficance. Speaking simplistically, it is their hypothesis and goal to identify the "key components" of bourbon's signature aroma.

Total: 8 important ("key") esters/compounds which accounted for the signature aroma of bourbon (in their estimation).

Am I buying this? Yes and no. Unlike the many hip shooters out there who stoop to a typical spray and pray approach, and who would reject this finding straight out, probably murmuring something like "...scientists will never really isolate why rum smells the way it does..." - I won't.

And it's not because I don't appreciate the art and mystery. And I can be as contradictory as anyone. And keep in mind that these very same hip shooters are also the ones that praise "classic rums" that have been adulterated with all manner of additives.

Here's what I think:

1. There is a distinct difference between high ester Jamaican styles (which contain up to 1700 esters) and most of the others (which average 50). The complex aromatics of the Jamaican style are well accepted.

2. Although I am sure that scientists may someday - I repeat someday - may isolate the most important, that even the "less important", in sum, contribute in some way to a fuller, more complex, more mysterious expression of the fundamental tones.

In music we might call this harmonics. Additional notes, tones, tremolo and the like add richness, body, complexity and emotion. Strip these away and the music suffers.

The stated goal of this study was to identify "key components" with an eye toward "changing the recipe or manufacturing processes for bourbon in order to produce whiskey with distinctive flavors".

Read: additives to enhance cheap whisky. Do you really think that corporate distillers will engage in endless and expensive experimentation to hopefully increase the percentage of these "key" components...

Or just toss a bucket of them into the vat before bottling?


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Note: for the complete study - click here.
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