Journal of the Institute of Brewing

Reflections

2026-05-04T12:38:16+00:00

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.

Carbonation of beer in microbreweries using a bulk gas-to-atomised liquid (BGAL) approach

2026-07-20T16:36:09+00:00

Why was the work done: In microbreweries, forced carbonation in a bright beer tank using a carbonation stone may require up to 72 hours to reach specification for dissolved carbon dioxide. The mass transfer kinetics in bubbled systems are generally poor due to the small surface area-to-volume ratio in the liquid phase. Alternatively, droplets of beer have a comparatively large surface area-to-volume ratio and can absorb gas at greater rates.

How was the work done: A bulk gas-to-atomised liquid (BGAL) process was evaluated for beer carbonation. Using this method, a spray of beer droplets is carbonated in a closed vessel pressurised with carbon dioxide gas and equipped with a nozzle to atomise the beer. Following testing at prototype scale (3 x 19 L), the approach was evaluated at a pilot scale by retrofitting a 240 L bright beer tank to accommodate a nozzle, and a laboratory brewed IPA was carbonated at a rate of 3.0 L/min.

What are the main findings: The rate of carbonation achieved by the BGAL system was between 3 and 50 times greater than conventional carbonation, the precise improvement was dependent upon the operating conditions for the conventional method. Further, analysis of the finished beer revealed that hop oil compounds in BGAL carbonated beer were statistically similar to the concentration in beer carbonated by conventional means.

Why is the work important: These results suggest that the BGAL system could enhance the carbonation step in microbreweries that use a carbonation stone in bright beer tank, while maintaining the aromatic characteristics of the beer.

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

2026-05-28T12:12:08+00:00

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.

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

2026-06-29T16:23:14+00:00

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.

Isolation from grain based starter and fermentation performance of high aroma strains of Saccharomyces cerevisiae in Korean rice wine

2026-07-21T16:36:59+00:00

Why was the work done: The quality and sensory differentiation of Cheongju rice wine require the selection of yeast strains that combine stable fermentation performance with desirable aroma profiles. However, indigenous yeasts from traditional fermentation starters have received little attention or comparative evaluation under standardised Cheongju fermentation conditions.

How was the work done: Strains of Saccharomyces cerevisiae were isolated from traditional Nuruk used in Cheongju production and screened using glucose and ethanol tolerance. Two selected strains were evaluated through seed (500 mL) and 5 L fermentations, with analysis of alcohol production, volatile aroma compounds, taste attributes, and enzymatic activity profiles. These were compared with a commercial reference strain of S. cerevisiae.

What are the main findings: The yeasts exhibited stable fermentation performance, producing alcohol concentrations of 17-19% (w/v). Cheongju fermented with these strains showed an enrichment of fruity ethyl ester compounds, with no differences in acetate ester formation. Taste analysis using an ‘electronic tongue’ showed reduced bitterness and a modest increase in umami-related attributes. Further, the strains had higher esterase and esterase-lipase activities than the reference strain.

Why is the work important: These findings highlight the potential of indigenous yeast strains to enhance aroma quality and sensory balance in Cheongju fermentation. The results provide a practical basis for yeast selection in rice wine brewing and support the development of optimised fermentation strategies for Cheongju production.