However, record-breaking daily maximum temperatures, warmer than average overnight temperatures, and increasingly erratic weather patterns are playing havoc with the way wine grapes grow and ripen. This has knock-on effects on Australian grape growers, wine producers, and consumers.
Climate in the Vineyard hits the Store Shelf and the Cellar.
The majority of Australia’s wine-producing regions have seen increasing average daily temperatures. Changes in ripening time have had a significant impact on the winemaking season.
White grapes have traditionally reached optimum ripeness ahead of red varieties. All grapes ripen more quickly as temperatures increase. Still, this effect is stronger for late-ripening varietals (such as Shiraz and Cabernet Sauvignon) than earlier ripening ones (such as Chardonnay or Riesling).
Australian wine grapes are ready to be harvested simultaneously. Shutterstock
Using staggered harvesting for white and red grapes was efficient because it allowed the winery to use its capacity in order for different types. As different grape varieties ripen at the same rate, wineries and vineyards will need to make difficult decisions about which grapes they should prioritize and which to delay, leading to inferior wine. They could also invest in expensive infrastructure, such as stainless steel tanks and fermenters, to increase their production capacity.
Read more: Message in a Bottle: The Wine Industry Gives Farmers a Taste of What to Expect from Climate Change.
Perhaps you’re thinking that you, the savvy wine drinker, are unaffected by the difficulties faced by winemakers in the vineyards and wineries far away. Unfortunately, this isn’t so. Harvesting grapes when they are not at optimal ripeness to solve the logistical problems of processing can lead to lower-value wine.
This new reality costs everyone, including grape growers and winemakers.
Think again if you believe that changing Australia’s cultural palates to beer is the easy solution. Climate change is also having a significant impact on hop production.
You can help
We hope to solve these problems. CSIRO announced a five-year research partnership with Wine Australia. One project aims to adapt the ripening of wine grapes to a changing climate.
Plant growth regulators are molecules used by plants to coordinate and control their development. Charles Darwin first studied auxins in grass seedlings in the 1880s. They play an important role in vine growth as well as the timing of grape ripening and development.
Plant growth regulators are a great way to control the ripening process. Shutterstock
Auxins are compounds that can be sprayed on vines or grapes just before they ripen. This could influence the harvest date. These compounds are used to control fruit drops in apples and pear trees.
Auxin applied in very small quantities can delay the ripening of grapes and, therefore, harvest by as much as four weeks (Davies et al., J Ag Food Chem, 63, 2137-2144, 2015). This treatment is effective for both red and white grape varieties in warm or cool climates. It’s also cheap, easy, and safe to use.
Wines made with grapes that have been ripened at a later stage are almost identical to wines made using untreated fruit harvested up to one month earlier. In Shiraz, auxin-induced ripening can be used to boost the concentration of rotundone. This compound is responsible for the popular peppery notes in this variety.
Read more: State of the Climate 2018: Bureau of Meteorology and CSIRO
Work is currently underway to fine-tune spray formulations and application times. The aim is to release a commercially available product within the next five years.
This solution is vital to the production of high-quality wines in established wine-growing regions. We hope that you will enjoy your favorite wine for many more years.
