Posted by: Didapper PJ26 JAN 2012
Much Scotch whisky will have been consumed around the world this week during Burns Night suppers. A few wee drams always accompany the obligatory main course of haggis, tatties and neeps, and a few more are usually included in traditional desserts such as cranachan and tipsy laird. And, of course, whisky is the drink used for the toasts to the haggis, to the “immortal memory” and to the lassies — and to any other people, places or institutions deemed toastworthy on the night.
Some whisky drinkers like their Scotch neat, some insist on adding ice and others prefer to contaminate the noble spirit with fizzy drinks such as cola or ginger ale. But whisky lore, particularly among single malt purists, says that the spirit is generally at its best when diluted (no more than 50:50) with a little soft water at room temperature to “release the flavour”. Ideally the water should be the same spring water that was used in making the brand you are drinking.
And research now suggests that for most whiskies the addition of a little water does indeed release the flavour and enhance the aroma. (Adding ice diminishes the aroma, although it does not significantly affect the taste.)
Researchers at the University of Strathclyde have tested the effect of dilution on the sensory impact of whiskies by assessing the compounds released into the “headspace” — ie, the part of the glass into which you stick your nose to take in the whisky’s aromatic notes. They found that dilution augments the release of some flavour compounds but masks others. This is because increasing the water content reduces the solubility of hydrophobic aromatic compounds, thus increasing their volatility and their concentration in the headspace; conversely, dilution reduces the volatility of compounds that are particularly water-soluble and so they tend to be lost from the aroma.
The effect of dilution is especially noticeable with the phenols that give the smoky or peaty aroma that characterises some single malt whiskies. Dilution reduces the pungency of these whiskies without compromising their flavour.
However, the research has also confirmed the view of malt connoisseurs that, unlike other whiskies, a well matured malt may be consumed neat. It appears that as malt whiskies mature they become less pungent than might be expected.