Journal of the Institute of Brewing

Reflections

David Quain — 2026-07-02

This issue of Reflections celebrates the contribution to the Journal of the Institute of Brewing of Professor Emeritus Graham Stewart who died in May aged 84. His academic and applied studies on brewing yeast and fermentation at Labatt’s in Canada (1969-1994) and at International Centre for Brewing and Distilling (ICBD) Heriot-Watt University in Scotland (1994-2007) resulted in significant insights and associated process developments with innumerable publications in journals, industry magazines together with books both - in his own right - and as co-editor. Between 1973 and 2013, he published 49 papers in the Journal of the Institute of Brewing and, in appreciation, his ‘top 10’ papers by citation are listed here. It is particularly fitting that two of the four papers in this issue of the JIB are from the ICBD.

Unravelling the art of feints recycling for whisky: a production survey

Matt Strickland — 2026-06-29

Why the work was done: Batch distillation is used globally to produce a number of different categories of spirit using a variety of methodologies. This work aims to gain a better understanding of the current institutional knowledge on batch distillation techniques for the various categories of whisky, including the recycling and processing of 'final runnings' or the 'tails' fraction.

How the work was done: A survey was designed to gain insight into current distilling knowledge and practice. Sixty distillers from eight countries respnded to the survey and reported their distillation practices with particular emphasis on how decisions are made regarding where the individual liquid fractions begin and end during distillation and how the feints ('heads' + tails') are subsequently handled.

What are the main findings: Of the 60 distillers surveyed, 59 responded that they recycled feints in some way and 93.2% of those respondents noted that the feints did appear to stabilise after a few distillation cycles. The majority (75%) noted that there is a cost benefit to recycling feints and 61.7% also felt that feints recycling improved the character of the overall spirit.

Why is the work important: Despite the prevalence of recycling feints, little is understood about how this process affects spirit character or why the phenomenon of stabilisation occurs. This and further research, will provide distillers with better insight into their practices and offer tools for continued improvement in spirit quality.

Quantifying the impact of increasing wash strength for Scotch malt whisky production: a modelling study

Shiwen Zhuang — 2026-06-11

Why was the work done: High gravity fermentation (ca 8% ABV) is used in the production of Scotch malt whisky but the impact of increasing wash strength on fermentation and distilling has not been quantified, especially in relation to environmental and operational performance.

How was the work done: A representative scenario of a 200 hL wash at 8% ABV was used to model wash strengths of 10-14% ABV under two conditions: the same wash volume (Condition 1) and the same ethanol mass (Condition 2). All scenarios were assessed quantitatively.

What are the main findings: In Condition 1, increasing wash strength enhanced batch production capacity but may require a larger spirit still or multiple distillation batches. In Condition 2, higher wash strength reduced batch processing volumes, enabling the use of smaller vessels without compromising the capacity for ethanol production. Distilling energy dominated the total energy demand, whereas fermenter cooling energy was negligible. On the basis of a litre of pure alcohol (100% ABV) and an annual target basis, increasing wash strength from 8 to 14% ABV progressively reduced energy use and carbon footprint by 15.8-16.1%, while also reducing post-distillation discharge volumes by 55.0% in pot ale and 30.4% in spent lees.

Why is the work important: This study provides quantitative evidence of the effects of increasing wash strength (8-14% ABV) on the operational and environmental performance in Scotch malt whisky production. This supports process innovation, capacity planning, and industrial decarbonisation strategies.