Profiling Peat For Whisky Production

The distinctive smoky flavor of certain Scotch malt whiskies arises from burning peat to dry the malted barley from which the spirit is derived. Now, scientists in Scotland have conducted a survey of peat from around that country to see if there are regional differences in the chemical profile of the decayed vegetation (J. Agric. Food Chem., DOI: 10.1021/jf803556y). Barry M. Harrison of the Scotch Whisky Research Institute and Fergus G. Priest of Heriot Watt University examined peat from Islay, Orkney, St. Fergus, and Tomintoul by using Curie point pyrolysis in combination with GC/MS analysis. Peat pyrolysates from Islay and St. Fergus were both rich in lignin derivatives, whereas those from Orkney and Tomintoul contained high levels of carbohydrates, which are known to produce caramel and burnt flavor notes. The depth of the peat extraction from the ground also had an effect on the material's flavor compounds. "Where peat is used in whisky production, the observed differences in peat composition could potentially impact flavor," the researchers write. This is an important consideration, they say, if a whisky maker decides to switch the source of its peat.