Char Morphology and Chemistry – The Key to Good Whisky

This PhD opportunity will primarily be based at Heriot-Watt University, Edinburgh.

Please contact Prof Martin McCoustra (m.r.s.mccoustra@hw.ac.uk) for further details.

Whisky production is a multi-billion-pound industry which at its heart is craft-based. The process is simple – freshly distilled spirit is put into a charred barrel and left to mature. The charred and toasted wood of the barrel provides a source of flavour and colour compounds for the aging spirit [1]. While the process is understood, a deeper understanding of the link between the toasted and charred wood of the barrel and the quality of the maturing spirit is necessary. We are working with Diageo through a knowledge transfer partnership (KTP) to develop that understanding. This project will complement and support the activities of the KTP Associate working on that programme.

This project will address the fundamentally important question of how the toasted and charred wood impacts the sensory characteristics of whisky as it matures. We will combine thermophysical models of the process of toasting and charring the wood, with sophisticated studies of char morphology using micro-CT scanning and flavour chemistry, as a function of depth in the toasted and charred wood, using a combination of mass spectrometric (GC -MS analysis on extracted materials [2], pyrolysis MS [3], ToF-SIMS [4]) and vibrational spectroscopic methods. The results of this work will be integrated into the machine learning structure that the KTP is to develop. This project will also look to further understand the impact of alternate, sustainable, heat sources on this model and the related implications for mature whisky flavour and colour.

The project will be based jointly in the Institute of Chemical Sciences, the International Centre for Brewing and Distilling, and the Institute of Mechanical, Process and Energy Engineering of Heriot-Watt University in Edinburgh. The project will also provide opportunities for collaboration with our KTP partner, Diageo Scotland Ltd., and the University of Nottingham in exploring the application of ToF-SIMS to analysis of toasted and charred wood. Interaction with the KTP Associate on our programme is expected.