Category: Chemistry

A while back, I visited the Bushmills whiskey distillery (it was my second visit in as many decades) always a pleasure, especially the tasting panel at the end of the tour just before you spend all your money on, ahem, souvenirs.

Whisky is a broad category of distilled drinks made from fermented grain mash and aged in wooden casks. Different grains are used for different varieties, including barley, malted barley, rye, malted rye, wheat, and maize (corn), certainly a favourite at holiday time and the subject of many a New Year’s Resolution. The fermentation liquid is distilled, sometimes several times, to produce neat spirit, which is then aged in casks. Different barrels, virgin oak barrels, pine barrels, used sherry casks, charred barrels, are used to produce different flavours.

It’s quite ironic that there are some 200 to 300 chemicals in the finished product including carbonyl compounds, alcohols, carboxylic acids and their esters, nitrogen- and sulfur-containing compounds, tannins and other polyphenolic compounds, terpenes, and oxygen-containing heterocyclic compounds, and esters of fatty acids any one of which would probably be banned under health and safety rules if you were inventing whisky as a product today. Indeed, the nitrogen compounds include pyridines, picolines and pyrazines, carcinogens on the rocks, any one?

Anyway, one aspect of the whole process from grain to bottled liquor that fascinates me is that the distilled liquid, the spirit, is an almost pure ethanol-water mix (an azeotrope). In fact, the tourguide at Bushmills told us that this was so and that the flavour is then all to be found in the aging process in the barrel. But, if that’s so, then it doesn’t explain the wide range of flavours of whiskys matured in similar casks, nor does it explain how the peaty fireside phenols of some Scotch whiskys, the Islay type for instance, are carried into the bottle.

As is my current wont, I twurned to Twitter to ask about this and hooked up there with Michelle Jones of justaddbourbon.com who asked some of her friends in the bourbon trade about the spirit of the water of life, so we’ve got a Stateside answer.

“Look at it this way, distillation provides the palette by which aging can work its magic. There is no doubt that American Whiskey was once a very harsh tipple. Once aging was introduced, it mellowed the whiskey considerably. But even that doesn’t wholly answer the question. Aging contributes differently based on time. Short aging might contribute a little more sweetness whereas long aging contributes smokiness and oakiness. But most people pick out mintiness and a long finish from Heaven Hill whiskeys. That is a result of the distillation process.”

Whisky lactone (3-methyl-4-octanolide) is present in oak, which is the most commonly used barrel material and endows whiskies with an essence of coconut aroma, while the diketone diacetyl (2,3-butanedione) gives the buttery aroma of most spirits. Commercially charred oaks used for aging barrels are particularly rich in phenols, with some 40 different phenolic compounds, having been revealed in charred oak barrels, each one of which can add to the flavour. The coumarin scopoletin is also present in whisky.

Oh, and just in case you thought I was being inconsistent with the whiskey/whisky spelling, it’s impossible to know which one should be used whiskey is often for Irish and American, and whisky for Scotch and Canadian, but it’s Maker’s Mark Bourbon Whisky (original distillers were Scottish) and Woodford Reserve Bourbon Whiskey (waiting on an answer as to whether they have Irish origins), and they’re made just 80 miles apart in Kentucky.

My latest science news is now online in the spectroscopyNOW ezine. This week:

Recycled virgin – Recycled engine oil has high levels of organic impurities, heavy metals, and carcinogenic compounds, according to work carried out by researchers in Jordan. They have used atomic absorption (AA), inductive couple plasma (ICP) and Fourier transform infrared (FTIR) analyses to spot the differences between virgin and recycled engine oil.

In a spin over nanomaterials – Researchers at Rensselaer Polytechnic Institute, New York, are hoping to spread the word far and wide of a new analytical technique that can help scientists and technologists working with nanomaterials. They say that their discovery could help accelerate the development of materials for the next generation of solar energy conversion and computer data storage.

Deadly proteins and trigger points – US researchers have used NMR to identify a previously undetected trigger point on a naturally occurring “death protein” that helps the body get rid of damaged or diseased cells. The researchers suggest that their findings may offer a novel target for new drugs that could be used to treat cancer by forcing malignant cells to undergo apoptosis, or cellular suicide.

Finally, a rather technical item that will appeal to that specialist niche working on time-resolved laser-induced fluorescence spectroscopy. German researchers have found a new way to fit a statistical model to TRLFS spectra that could reveal hidden details and remove background noise, much more effectively than before. The method could allow samples containing various radioactive elements to be analysed effectively despite the interferences from the different ions present.

This week the Alchemist hears how polymer chemists are turning to supramolecular chemistry (or is it supramolecular chemists turning to polymers?) to create novel flexible and elastic materials. In nanotechnology, a British consumer activist organization is calling for more safety data on nano materials used in cosmetics, and French scientists have demonstrated how nitrogen oxides released by snow melt in the Arctic could have a global impact.

In biological research, US scientists are suggesting that a specific active form of vitamin D could be useful as a protective agent against nuclear incidents. And, in interplanetary chemistry, Johns Hopkins researchers have found spectroscopic evidence that water-bearing opal formed on Mars much more recently than previously thought.

Finally, we’re going Dutch with this week’s award in which technology transfer in the area of solar energy conversion brings a financial reward and prestige to a graduate student and his colleagues. Get the full skinny and the links in current issue of The Alchemist

In the latest scary issue of the chemistry news webzine, Reactive Reports: Dating skeletons, sticky feet for Gecko Guy, volcanic chemistry from the depths of Hades, and chasing mad cows.

CSI: Waco – A statistical method that processes spectroscopic measurements very quickly could allow crime scene investigators to determine time of death of skeletal remains more accurately and quicker than before, according to researchers at Baylor University in Waco, Texas.

Stuck On You – Scientists have long been interested in the ability of gecko lizards to scurry up walls and cling to ceilings by their toes. Now, researchers have found a way to mimic those hairy gecko feet using polymers or carbon nanotubes.

Tubular Reactions – Using surface-modified carbon nanotubes to activate an important industrial chemical, butane, without the need for an expensive metal catalyst–Dang Sheng Su and his team present a process that offers a cheaper alternative to the current industrial process for butane activation.

Chasing Down Mad Cows – Researchers in Europe have tracked down the molecular anchor that hooks errant and infectious prions leading to mad cow disease, scrapie in sheep, and Creutzfeldt-Jakob disease in humans.

The Nobel Prize for Chemistry 2008 was awarded to Osamu Shimomura (b. 1928) of the Marine Biological Laboratory (MBL), at Woods Hole, Massachusetts and Boston University Medical School, Martin Chalfie (b. 1947) of Columbia University, New York, and Roger Tsien (b. 1952) of the University of California, San Diego, La Jolla, “for the discovery (1962 by Shimomura) and development of the green fluorescent protein, GFP”. Important, of course, and congratulations to all three…but I just knew it would be bio again!

The Nobel org press release for the Chemistry Prize can be found here.

The remarkable brightly glowing green fluorescent protein, GFP, was first observed in the beautiful jellyfish, Aequorea victoria in 1962. Since then, this protein has become one of the most important tools used in contemporary bioscience. With the aid of GFP, researchers have developed ways to watch processes that were previously invisible, such as the development of nerve cells in the brain or how cancer cells spread. Of course, the things that the public know about GFP are the green-glowing mice and pigs that have hit the tabloid headlines over the years.

I’ve written about green fluorescent proteins (although not green fluorescent proteins) on several occasions over the years. Briefly in an item on artificial cells in December 2004. In Reactive Reports in September 2005. In New Scientist (“Genetic Weeding and Feeding for Tobacco Plants”, Jan. 4, 1992, p. 11). In SpectroscopyNOW in January 2008. And, more substantially, in American Scientist (January 1996) on the use of a green-glowing jellyfish protein to create a night-time warning signal for crop farmers. Plants under stress would activate their GFP genes and start glowing, revealing which areas of which fields were affected by disease or pests and so tell the farmer where to spray. Of course, the idea of green-glowing cereals would have any tabloid headline writer spluttering into their cornflakes of a morning.

As I said earlier in the week, on the post for the Nobel Prize for Medicine 2008 and on the Nobel Prize for Physics announcement yesterday, the Nobel press team has employed various social media gizmos to disseminate the news faster than ever before, including SMS, RSS, widgets (see left), and twitter.

You can check back here later in the week and next week for the Literature, Economics, and Peace Prizes, the widget at the top left of this post will provide the details as soon as they are released. It’s almost as exciting as sniping your bids on eBay.