The 2007 Barth Haas Grant Winners are:

Christian Brandt, Prof. K. Wackerbauer, VLB Berlin, Germany

The impact of reduced hop extracts on beer flavour stability in clear glass bottles

Facing the fact of the increasing use of clear glass bottles in the brewing industry, it gets more and more important to do research on prevention of off-flavours in beer, especially when it is exposed to light. Therefore, an optimal solution would be to brew beer with raw materials which are less susceptible to form off-flavour components in order to guarantee a long shelf life and flavour stability without further negative effects on flavour or other qualities of beer at all. Hence this diploma thesis is to deal with the specific ageing characteristics of conventional CO2-hop-extracts, iso-hop-extracts and reduced-isohop- extracts (Rho, Tetra, Hexa) not only between these groups, but also within the category of reduced iso-alpha-acids.

Annette Schmelzle, Prof. Dr. B. Lindemann, FachhochschuleWiesbaden, Germany

The Methodology of Characterising Olfactory and Gustatory Perceptions in Beer.

The purpose of this project is to develop a methodology to characterise the aroma, taste, flavour and trigeminal sensations of specific types of beer with the goal of being able to describe and quantify the olfactory and gustatory properties, specifically those brought about by the use of hops in the brewing process. Focussing on Pilsner, Bitter and Indian Pale Ale, lists of positive attributes will be developed for sensory evaluations. The beers will then be evaluated using these attribute lists and repeated for statistical analysis. This will be assessed using an appropriate software.
The results possess the potential to aid in quality assurance, research and product development.

Stefan Hanke, Dr. M. Herrmann, TU München-Weihenstephan, Germany

Investigation of the linalool transfer rate and hop aroma in beer

Hop aroma is diverse and hard to describe. Linalool was found to be a good indicator substance in this regard. With a linalool concentration of 20µg/l a hoppy aroma can be regcognized in beers. To achieve a consistent hoppy aroma in beer the up-to-date way of usage of aroma hops is not ideal. Until now mostly the second hop addition takes place at the end of boil or into the whirlpool based on the alpha acid content. Since the ratio linalool/alpha acids depends on crop year, variety and provenience the dosage according to the alpha acid content results in different concentrations of linalool. Also the dosage according to the general content of hop oil is not ideal as the composition of the oil is inconsistent too. The aim of this project is to develop a method to improve the determination of important hop oil substances. In subsequent brewing trials with different german aroma hop varieties the hop aroma addition will be based on the linalool content of the used hop pellets and evaluated. The results should help the brewers to brew beers with a more consistent hoppy aroma.

Anne-Catherine Vandeville, Prof. P. Hughes, Heriot-Watt University, UK

The effects of hop-derived antifoams on the behaviour of top-fermenting yeasts

Initial research that investigated the impact of hop-derived antifoams on the processing and final product quality of ale and lager beers showed that the ale fermentations were sensitive to increasing doses of antifoam added to fermenter. This project will extend the previous work to address two
questions: Were the observations on the ale fermentations and final products due to the specific yeast strain, or to the top fermenting phenomenon itself? Does the use of hop-derived antifoams, rich in natural lipids, affect the growth of yeast during fermentation, thereby affecting fermentation performance? Four top fermenting strains will be sourced. Each fermentation and maturation will be monitored daily for a range of relevant parameters. Additionally, some preliminary investigations on the metabolic state of the yeasts will be carried out.

Rehilevich Andrej & Yarashynskaya Aksana, Prof. H. M. Milosta, Grodno State Agricultural University, Grodno, Belarus Republic

Evaluation of brewing characteristic of different hops varieties planted in Belarus Republic

In the former USSR main hops growing areas were in Russia and Ukraine.
Therefore previous research work rather focussed on studies of Russian and Ukrainian hop varieties. Within a bigger research project that investigates the soil and climate conditions for “foreign” hop varieties in Belarus this specific project will evaluate the brewing characteristics of various hop varieties (german and others ) planted in Belarus in order to determine the most suitable hop varieties in accordance with e. g. the Belarus nutrient soil input.