AWRI helpdesk project
This project provides helpdesk support for technical problems encountered by Australian grapegrowers and winemakers. Support includes identifying the root causes of problems, and providing research-based, practical, up-to-date remediation solutions, as well as future prevention strategies. This service also ensures that Australian grapegrowers and winemakers are competitive on the world stage, by having the latest technical information readily to hand. Investigative services, including analysis of problem grapes or wine, are conducted when a problem cannot be solved through discussions with the producer.
During 2019/2020, 3,400 enquiries were received (Table 2). This is approximately 1,500 more enquiries than recent years, predominantly driven by the unprecedented bushfire events experienced in the past season. This is also the first year that more than 500 sustainability enquiries were received (Figure 2). The majority of enquiries were from grape and wine companies and suppliers actively aligned with the wine industry, with a small number coming from government organisations, students, legal practitioners and journalists. Figure 3 shows that the sources of enquiries were broadly in line with the proportional volume of wine-grape plantings for each state/territory, with slightly more queries than normal for fire-affected states such as Victoria and NSW.
Helpdesk enquiries are classified using more than 40 different keywords. The number of queries received under each keyword is compared to historical monthly data collected over more than 20 years, to help identify national, state and regional trends. This allows for prompt responses to emerging issues and timely provision of relevant information. Figure 4 shows the queries from 2019/2020 arranged from most to least used keyword, highlighting key events or issues that occurred.
During the year, the viticulture team responded to 808 enquiries, with the largest proportion of these (537) on topics related to climate and sustainability. Drought was a key issue for growers, given that many Australian regions had been in drought for several years and received significantly below average rainfall during the growing season. Where soils were very dry and insufficient water was able to be applied through the growing season, the amount of harvested fruit was significantly reduced. Other climate-related topics where queries were received included frosts, hail damage and strong winds or hot weather during flowering, which had a negative impact on fruit set in some regions.
The largest number of winemaking queries received this season (48%) were about bushfires and smoke taint. As part of the AWRI’s smoke response, the helpdesk interpreted more than 4,300 smoke analytical results. More than 70 different grape varieties were submitted for smoke analysis from 47 different wine regions. Of the samples submitted, more than 75% were grape maturity samples analysed to give producers the information needed to make decisions on whether to harvest fruit, based on evidence of smoke exposure.
In March, technical enquiries began regarding COVID-19, mainly regarding how to operate within recommended restrictions and what to do if a staff member in a vineyard or winery tested positive for the virus, including any specific remediation or cleaning requirements for grape and wine production facilities. A review of cleaning and sanitation agents suitable for winery environments was conducted and an eBulletin and webpage produced addressing these questions. Queries were also received about the risk of the SARS-CoV-2 virus surviving in wine.
Winemaking problem-solving investigations
This year only 6% of winemaking enquiries resulted in investigations, where samples are requested and analysis performed to identify the problem and recommend a solution. This is lower than the usual 20% of enquiries resulting in an investigation, mainly due to the overriding number of smoke analysis interpretations. The helpdesk team conducted 166 problem-solving investigations on 904 samples (Table 3). This was approximately 40 fewer investigations than recent years; however, the number of samples submitted is similar, showing that this year’s investigations required larger numbers of samples than usual. As for enquiries, use of the problem-solving investigative service was mostly in line with the proportional volume of wine-grape plantings for each state/territory, with slightly more investigations conducted for Victorian producers than in previous years (Figure 5).
Winemaking investigations are assigned to five main categories: hazes and deposits; sensory investigations; microbiological issues; taints and contaminations; and other. The proportion of investigations in each category has remained relatively consistent over the last ten years, with approximately 20% in each category (Figure 6). Closures is an additional category where investigations were common in the past; however, investigations in this category are now relatively rare because of the widespread uptake in Australia of non-cork-based closures.
Hazes and deposits
There were slightly more haze and deposit investigations this year than the ten-year average. One-third of the hazes and deposits identified were crystalline, with two-thirds of these identified as calcium tartrate, similar to last year. These crystals form over time post-bottling and are caused by elevated calcium levels rather than ineffective cold stabilisation for potassium hydrogen tartrate (KHT). Another third of the hazes and deposits were protein instabilities, and a further third classified as ‘other deposits’, a wide-ranging category including anything from pieces of packaging materials (from cork to fragments of bottle dividers) to, unusually, even a piece of meat!
There were fewer microbiological investigations than the ten-year average this year, which is a promising sign. Specific microbiological issues encountered included elevated acetic acid concentrations in wine caused by bacterial spoilage, ‘mousy’ off-flavour and Brettanomyces spoilage.
Sensory issues investigated by the helpdesk are often related to oxidation or sulfide development. This year sensory investigation numbers remained high (Figure 7), with additional investigations conducted related to indole formation in sparkling wine.
Taints and contaminations
This category of queries was dominated by chlorophenol and ‘musty’ taints in wines. There were also investigations comparing smoke analytical results with the sensory perception of ‘smoky’ characters as assessed by the AWRI quality panel.