Slainte! To The Science Of Scotch!

scotch1.jpgScotch isn’t really my thing, but I was excited nonetheless to learn a bit about the science of the drink last night at the New York Academy of Sciences. Simon Brooking, master ambassador for Laphroaig and Ardmore, two of Scotland’s premier single malt whiskeys, gave a rollicking talk that covered everything from the history of the drink to how it's distilled to a primer on tasting and enjoying the drink (a hint: let it hit the middle of your tongue, not the tip). There were bagpipes and kilts and several kinds of Scotch to sample. Brooking even sang a few songs.

Our own Beth Halford did a thorough job explaining the process of distilling whiskey, so I won’t go into the gritty details. But I did come away with a few interesting facts worth sharing:

*The Scots use copper stills when making their magic elixir, and Brooking says the style and the flavor of Scotch is linked to the shape of the still and the angle of the line neck. Smaller, squat stills tend to produce a heavier, oilier-flavored drink, whereas taller stills impart a sweeter flavor. When I asked Brooking to clarify why the shape of the still mattered so much, he said “we’re not sure exactly what is happening,” chalking up the process to the magic and mystery of Scotch. Hmm. Not exactly the scientific breakdown I was hoping for. He did explain that different parts of the still wear thin sooner than others because of the heat generated while the whiskey is refluxing, which could influence the final product. I did a little digging, and it seems the copper reacts with sulfur compounds that would otherwise give the whiskey an unpleasant taste. I’m sure there’s more to it, chemically speaking, and would guess surface area also plays a role. Perhaps one of our readers could provide some more clarity?

*Scotch is distilled twice (the Irish distill their whiskey three times) to ensure the acetones and acetates are removed from the drink. According to Brooking, the term “blind drunk” derives from the deleterious effect of drinking whiskey that has only been distilled once.scotch2-barley.jpg *Much of the flavor is determined by the peat burned to dry the barley, so logically, you’d expect a variation of flavors based on where the peat came from. Laphroaig is based in Islay, an island off the Western coast of Scotland, and its whiskey has super smoky, sea salt, and seaweed flavor. Ardmore, on the other hand, is made in the Highlands, and the peat in that region reflects the heather in the area. The whiskey, as a result, is more floral and honeyed.


*The myriad flavors you detect in Scotch may come from any of the following compounds: formic acid gives it a pungency; hexanal, a grassiness; hydrogen sulfide, a yeasty flavor; diacetyl leaves it buttery; and whisky lactone imparts a nutty, coconut-ish flavor.

*Most Scotch used to undergo chill filtration because the fatty acids in the liquor congeal when they undergo a major temperature change. The spirit gets a bloom—or turns cloudy—and distillers thought consumers wanted a clear drink. Now, however, there’s a turn away from chill filtration because distillers fear essential oils—and essential flavors—are being lost in the process.

Also worth noting: The organizers provided a little preview of what to expect in the next academic year at the NYAS. Starting in September, they are abandoning the food focus to do a series on the Science of the Five Senses. Each talk will pair a researcher with someone on the arts side. For two of the sessions, science writer (and this year’s winner of the ACS Grady-Stack award) Harold McGee and otolaryngology specialist Linda Bartoshuk will talk about taste, and author Diane Ackerman and Rockefeller University professor Leslie Vosshall will discuss smell.

Author: Lisa Jarvis

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  1. From where I stand, what Brooking says about the shape of the still sounds more like superstition than science. However, the shape of the still might affect the rate at which flavor chemicals are transported. So the shape might determine which chemicals are left behind.

  2. mmm, suddenly I have the urge to perform some in depth chemical analysis upon a nice scotch..

    Maybe the shape of the still top has some effect on the volatile compounds that come over into the distillate. I’m wildly speculating, but perhaps the different flavor compounds have a boiling point near the temperature of the still head, different geometries of still heads may lead to some vapors condensing and dripping back into the still instead of moving into the condenser and down into the distillate.

  3. no wonder scotch gives me terrible heartburn