Smoke Taint Risk Calculator (STAR)
A comprehensive computer-based software tool has been developed by DAFWA and The University of Western Australia to reduce the incidence and severity of smoke exposure on grapes and wine. The tool can predict the seasonal vine phenological stage and associated susceptibility of the vine to smoke uptake and effect on wine. This tool can also be applied in prescribed burning decisions. The Smoke Taint Risk calculator (STAR) is available on the DAFWA website.
STAR uses a growing-degree-day phenology model based on temperature to predict the seasonal grapevine growth stages for different wine grape varieties. Inputs can be entered at any time during the season to generate the predicted smoke taint risk for key varieties in any growing region in Australia. STAR integrates this information to produce a time series graph of predicted smoke taint risks.
STAR incorporates elements including vineyard location mapping, knowledge of seasonal growth stages, smoke risk factors, in-field smoke detecting equipment and an interactive software interface. It has unrestricted access and the website contains information on how to use the software.
Vineyard location mapping
Vineyards are found over diverse landscapes and large geographical areas. They are predominantly in recognised Geographical Indications (GI) regions that are formally established to encompass regional wine grape production. In general, most production is in recognised GI regions, however, some vineyards may be outside these regions.
Wine production can cover large areas adjacent to other activities such as horticulture, agriculture, forestry and urban development. As part of the smoke risk reduction model, it is imperative to know where vineyards are located and their heaviest concentrations. This is of key importance in managing competing activities and scheduling of prescribed burns to avoid conflicts with wine grape production.
Knowledge of vineyard locations is essential where owners need to be contacted if smoke or biosecurity issues arise. When fires do occur, the spread of smoke can be tracked by aerial photography to see if it corresponds with wine production areas.
DAFWA has developed a process to capture and map vineyard locations. This has been piloted in WA and can be reproduced elsewhere in Australia. It includes sourcing aerial maps from Landgate that are inspected to identify land areas that contain vineyards.
Each vineyard is identified and its owners contacted and provided with a hard copy map of their property to confirm wine grape production. All owners are requested to provide contact details, area of wine grape production and varieties. This information is entered into a comprehensive and secure database. The locations of vineyards are used for communication on potential smoke events and in planning prescribed burning.
Timing of key growth stages
Research has shown the risk of smoke uptake and development varies depending on the vine growth stage. Therefore knowledge of the true phenological growth stage can determine the potential risks. Timing of growth and development is highly dependent on temperature, with variability of stages due to climate, region, seasonal conditions and variety.
In order to gain a greater understanding of seasonal variability of growth stages, a pilot study was conducted in WA. Researchers obtained historical phenological records from producers and seasonal records from 2011 to 2012. Results showed the timing of key growth stages varied greatly between regions and even within a region. This information is important and needs to be considered at each site to determine the true timing of grapevine sensitivity to smoke uptake.
Calculation of risk factors
Smoke risk factors incorporated into the STAR model have been based on field research and generated from both the chemical and sensory properties of wine. It covers key varieties including Merlot, Cabernet Sauvignon, Chardonnay and Sauvignon Blanc. The number of varieties will increase as research progresses in this field.
Smoke detection in the field (nephelometers)
Understanding the timing of smoke exposure and its associated density and duration provides information on the likelihood of taint in the final wine. In order to identify if smoke has been present in the vineyard, smoke detection equipment can be employed.
A number of reliable units are available, including particulate monitors, atmospheric gas detectors, nephelometers and visual monitors (web cameras), all with a variety of functions.
In DAFWA research, nephelometer equipment has been used reliably to quantify smoke presence in the vineyard. Nephelometers use a light detector to measure suspended particles in the atmosphere, with the density of these particles related to their light reflectance.
For any smoke detection equipment in the field it is important to consider its function. Cost, portability, weather stability, power source, data download capability and data interpretation also need to be considered.