This project underpins and enables the AWRI’s research, development and extension activities, through the provision of a range of cost-effective essential supporting services and efficient access to critical infrastructure. Specialist capabilities such as those of synthetic organic chemistry, expert instrumental equipment expertise or sensory science, including an available pool of screened, trained and qualified sensory assessors, are critically important for advances in wine science.
The AWRI runs several types of sensory evaluation methods: an expert technical quality panel, trained sensory descriptive analysis, difference testing and consumer hedonic testing. During 2017/2018, the technical quality panel evaluated 210 wines, as well as numerous training samples and research trial wines in preliminary ‘bench tastings’. In the same period 27 major descriptive analysis studies were completed using the AWRI’s highly trained external sensory panel. For most of these projects, the judges rated the intensity of carefully selected appearance, aroma and flavour attributes over multiple replicated occasions. In addition, projective mapping (Napping) studies to characterise similarities and differences among a set of wines were carried out regularly.
The studies in 2017/2018 included a large project conducted in collaboration with SARDI assessing the effect of grapevine clone on wine flavour. Several studies assessing closure performance were completed, as well as projects assessing flavour contributions from yeast strains, novel bitter compounds, white wine texture, water addition and viticultural treatments. A consumer preference study was completed in Sydney to evaluate the degree of acceptance of white wines with added flavour precursors derived from grape skins.
Difference testing, generally using the method of triangle testing, is an important sensory technique commonly used to find if a treatment has had a perceptible effect on wine aroma or flavour. Approximately 60 AWRI staff have been screened and are qualified to perform this task, usually assessing two or three sets per session. More than 65 tests were completed 2017/2018.
A major achievement during the year was the recruitment and training of an additional 12 part-time panellists, meaning that capacity for running sensory tests has greatly increased. Improvements to computerised data acquisition and statistical analysis methods also increased productivity.
Synthetic organic chemistry
The synthesis of important analytical standards and other chemical compounds required for mechanistic studies or sensory investigations is of great benefit to the AWRI’s research. When compounds are not available commercially, or are prohibitively expensive, the ability to produce them in-house is invaluable. The confirmation of the purity of analytical standards used for quantification of key aroma compounds has been a focus in the past year.
Aroma compound analysis
High-tech analytical instruments, including gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS), are carefully maintained to ensure they are in optimal operational order and capable of being used continuously to give timely results. Accurate and precise analytical methods for targeted aroma compounds were applied in many projects. Important compounds such as norisoprenoids (‘fruity’, ‘violets’, ‘kerosene’), thiols (‘tropical fruit’, ‘struck match’, ‘box hedge’), monoterpenes (‘citrus’, ‘floral’), rotundone (‘pepper’), oxidative compounds (‘honey’, ‘bruised apple’) and C6 compounds (‘green’, ‘grassy’) were quantified in more than 300 samples. Some of these analyses are also available on a fee-paying basis through AWRI Commercial Services. In this period, improvements to training and operating procedures streamlined methods, with newly recruited staff better able to look after instruments to achieve high quality data outcomes. Acquisition of two LC-MS instruments, used for thiol analysis as well as for quantification of smoke taint compounds, has taken the ability to schedule and run samples to a new level.