Malt for Scotch Whisky ProductionsInfluence of
Geographical Source and Extraction Depth
BARRY M. HARRISON*,† AND FERGUS G. PRIEST‡
Scotch Whisky Research Institute, Riccarton, Edinburgh, EH14 4AP, United Kingdom, and
International Centre for Brewing & Distilling, Heriot Watt University,
Edinburgh, EH14 4AS, United Kingdom
Peat is burned during malt kilning to provide flavor compounds in Scotch malt whisky. The aim of
this work was to establish whether peats from different locations in Scotland are chemically distinct
and could impart different flavors. Peat samples from four locations (Islay, Orkney, St. Fergus, and
Tomintoul) were analyzed using Curie point pyrolysis in combination with gas chromatography-mass
spectrometry (Py-GC-MS). Peat pyrolysates from Islay and St. Fergus were rich in lignin derivatives,
while those from Orkney and Tomintoul had higher levels of carbohydrate derivatives. Also, Islay
and Orkney peat pyrolysates were rich in nitrogen-containing compounds and aromatic hydrocarbons,
respectively. The depth of peat extraction was found to have an additional effect on peat composition
as the levels of carbohydrate derivatives reduced with increasing depth. Where peat is used in whisky
production, the observed differences in peat composition could potentially impact flavor, an important
consideration if the peat used for malt production is changed by either choice or necessity.
Table 4. Pyrolysis Products of Peat from Different Depths at Two Sites: Orkney (Op0 to Op4) and Islay (Ip0 to Ip3)
sample no.
carbohydrate
derivatives (%)
guaiacyl
compounds (%)
syringyl
compounds (%)
phenols
(%)
nitrogen-containing
compounds (%)
aromatics
(%)