I am not a
Scotch whiskey drinker myself, but I am related to quite a few. And something I have
noticed about all of them is they always add a little water to the glass
as well. I thought this was strange because I assumed it would dull the flavor.
However, my father, a self-proclaimed connoisseur of Scotch whiskey, told me
that the water enhances the flavor. I decided to investigate the topic.
An article
written in Discover magazine describes the research of Bjorn Karlsson and Ran
Friedman of the Linnaeus University Center for Biomaterials Chemistry in Sweden.
Their research focused on the main components of a fine Scotch whiskey: water,
guaiacol, and ethanol, otherwise known as the “big three”.
Scotch whiskies
are known for their rich, smoky flavors. These pungent flavors are created by
phenols, and guaiacol, being the most prevalent phenol in Scotch, produces a particularly smoky aroma. It is found in
higher concentrations in Scotch whiskies, more so than American or Irish ones.
This is due to the fermentation process used to produce Scotch whiskey. The
malted barley is smoked and fermented over a peat fire, which produces a large cloud of smoke instead of a flame. Interestingly, guaiacol
is also the active ingredient in anti-cough medication.
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| Chemical Structure of Guaiacol |
In regards to the other two components of the “big three”, the ethanol latches onto the guaiacol molecules and clusters them together in clumps during the fermentation process. During the process of Scotch distillation, ethanol concentration were found to be about 59%, so therefore the more guaiacol become stuck together due to the higher concentration of ethanol. The whiskey is then diluted approximately 40% before it is bottled. The bottling process causes the ethanol and guaiacol clusters to accumulate near the surface. Once someone purchases the bottle (after the appropriate amount of aging years) they are supposed to add a splash of water to a tulip shaped glass with the Scotch.
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| Chemical Structure of Ethanol |
When the
water is added, it dilutes the ethanol causing it to dislodge from the guaiacol
and causes both compounds to aerosolize. That is why Scotch has such a pungent
smell. Since taste and smell are so closely related, if you can smell it, you
can taste it. However, if there is too much water added the compounds will lose
their aerosolizing effect, thereby lose some of their flavor. In addition, gently swirling the glass causes the
other phenols along with the guaiacol to jostle around, thus enhancing the
aroma. The tulip shaped glass is used to funnel these molecules into the
nostrils so you can get the full effect of the smell. Every Scotch whiskey is
composed of its own variety of aromatics that are unique to the location and
manner it is bottled, that is how you get different aromas for different brands
and bottles.
Upon the
first read through of this article summarizing the research done by Bjorn
Karlson and Ran Friedman, I thought it was an article of strict factual basis. However,
when I reread it I noticed there was subtle humor and it seemed a more
light-hearted article. It also ended with the author mentioning how gin, rum,
and brandy can also be further enhanced using chemistry. Overall, this article
portrayed chemistry in a positive light by mentioning the benefits of certain
chemical properties as well as use subtle humor to highlight this point.
Rather an interesting topic. It seems the chemistry of whiskey is quite complex. The clustering of flavor molecules around ethanol is an interesting physical chemical effect. Your explanation is quite clear. Cute title. Too bad one structure didn't come through (stuff like this happens). It would be helpful to include links to your sources in the text.
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