Making Scotch : Engineering , Chemistry , and Education

During two successive summer hands-on whisky making classes at the Bruichladdich Distillery on Islay in Scotland, two types of samples were taken and analyzed using GC/MS. Samples were taken periodically during the two stages of distillation, and of whisky that had matured for different periods of time in different character casks. HYSYS engineering software was adapted to the batch distillation processes using the samples for parameterization and validation. The pot stills were modeled as having equivalent trays and internal reflux from condensation of the less volatile components on the copper walls of the stills. The maturation samples are being used to elucidate the physical and chemical interaction between the toasted, charred, and previous used barrels and the maturing whisky. The effect of transforming the boiling phenomena in the wash still (1 stage) from nucleate to film boiling to break the head was utilized. Phase separation was observed upon distillate condensation resulting in the transformation of the distillate in the spirits still (2 stage) from the first cut (foreshots) to the second cut (spirits cut i.e. product) indicated the decay of the concentration of ethyl acetate and acetal. The enhancement of flavor by phase separation caused by addition of water to whisky was also noted. The equilibration in a receiving tank of the wash still product (low wines) with the foreshots and tails (third cut) of the spirits still to form the feed for the next spirits still batch that enabled stable operating conditions was observed. The students who participated in each summer’s class earned academic credit either for the required senior laboratory, or as a special topics course on either the undergraduate or graduate level. A team of four senior ChE students did a project in the required design class on potential usage of the CO2 generated during fermentation. Introduction The University of Tennessee (UTK) Chemical Engineering Department and the Bruichladdich Distillery on Islay in Scotland cooperated in hands on whisky making classes during June 2003, and May 2004 and by the time of this conference will have had another class during May 2005. Hands on whisky making classes at Bruichladdich were conceived by Jim McEwan, have evolved to the Bruichladdich Single Malt Academy open to the public, and initiated with the UTK ChE department and the Colliers. Samples of the distillates in the wash and spirits pot stills, and from different age whiskies were taken by the UTK group, shipped back to the University, and analyzed at the Bush Brothers research laboratory in Knoxville. The UTK students earn academic credit for