Ways Grape Growers Can Clear the Air To Combat Smoke Taint

Smoke taint in grapes can strike in an instant. Worse yet, the damage might not be evident for months.

Wineries in the Okanagan Valley in British Columbia are learning as much this year after being hit by wildfires last summer. Blue Mountain Winery, an estate in Okanagan Falls, site of the Thomas Creek fire, in April relayed bad news to its wine club and loyal customers:

“The winery’s estate vineyards were impacted by smoke contamination. While attempts to mitigate the impact of the contamination were tried, the results did not meet the winery’s quality standards. We made the very difficult decision not to bottle the 2021 vintage simply because we were not willing to compromise the reputation that we have worked tirelessly to establish over the past three decades.”

Could anything have been done over the last year to prevent or remedy such a situation? Three companies — Agrology, Purfresh Wine, and UPL — discuss the topic of smoke taint:

Why should growers be more concerned about smoke taint?

Adam Koeppel, Founder and CEO, Agrology: “Wildfires are unfortunately an ongoing threat in today’s world. The rapidly changing climate means that farmers can no longer operate as business as usual, and things happen quickly. Smoke taint can directly impact an entire crop in the blink of an eye. That’s why it’s important that growers find new ways to predict and mitigate the threat of wildfires and smoke taint.”

Christian DeBlasio, CEO, Purfresh Wine: “The effects of climate change continue to cause increased wildfires of larger sizes and for longer periods in many key growing areas, including California, the Pacific Northwest, and Australia. The more wildfires there are, and the longer they last in an area, the more likely they are to cause serious smoke taint damage to wineries’ grape harvests.”

Emily Smith, Technical Service Manager, UPL: “We have seen first-hand how detrimental smoke risk can be to vineyards. In many cases, smoke taint has led wineries to completely scrap their grapes due to smoke taint. In order to make informed decisions about your operation, awareness of wildfires local to your vineyard need to be top of mind.”

How does your technology help growers?

Koeppel: “Agrology brings data from the field to the table. Growers and wineries have data in an easy-to-read dashboard that gives them the exact measurement of the compounds that cause smoke taint. Combined with targeted lab testing, it allows growers and wineries to make a very data-driven decision on what to do next.”

DeBlasio: “Purfresh Wine uses complex ozone (O3) airflow technology, pre-crush, to remove smoke taint molecules from grape skins and stimulate cellular defense mechanisms within the wine grapes, including biosynthesis of antioxidants, which generates additional natural wine flavors to overcome smoke impacts. A March 2021 Australian Wine Research Institute Molecules study demonstrates the efficacy of ozone treatment as a mitigation strategy for smoke taint.”

Smith: “Growers need to have access to in-depth information about the fires in their area in order to make informed decisions about their operation. This is why UPL created Crop S.A.F.E., an online platform that utilizes advanced data to provide critical updates on a variety of factors that affect crop production decisions, including high accumulated risk of smoke taint, temperature history, daily ozone and particulate data, air quality, wind direction, and more. This allows them to determine the best course of action for their vineyard and reduce the concentration of smoke-related aromas, flavors, and compounds in the final wine. A grower could decide to hand-harvest or harvest fruit early to minimize skin breaking or rupturing for as long as possible.”

Agrology’s monitoring sensors can be deployed across a crop to collect data on nano-climates, regions, weather patterns, air quality and ground truth, all of which can be used to predict environmental problems, such as smoke taint.
Photo by Adam Koeppel

How difficult is it for a grower to diagnose the problem? As University of California, Davis smoke taint expert Anita Oberholster notes, “grapes can have smoke exposure without having smoke taint.”

Koeppel: “It’s a challenging problem to diagnose. We’ve measured smoke in vineyards that didn’t cause any problems, since it was old smoke from distant fires. To a grower, it’s impossible to differentiate the problematic smoke. With Agrology, we collect the data that shows how many VOCs [volatile organic compounds] and fine particles reached each particular block. It gives them the data to then decide when to baseline test, harvest, how to process, etc. We work closely with Anita, and she is a supporter of our work.”

DeBlasio: “Growers can send wine grapes to a laboratory to see if they chemically show indications of serious smoke impact, and they can also process small bucket or micro-fermentations. Most moderate-level, smoke-impacted wines must be tasted post fermentation to fully understand the long-term viability of the wine.”

When are grapes most susceptible?

Koeppel: “Obviously when grapes are closest to harvesting, that is the most volatile time. It’s also the time of year when most extreme wildfires happen. But we alert growers to smoke exposure throughout the season to help establish baselines and to track development throughout the season.”

DeBlasio: “Wildfire season in Northern California runs from July until October, with the dry season getting longer every year. Significant impact of smoke in wine grapes appears to accelerate when the grapes pass the veraison period of their growth cycle.”

When should grapes be monitored/tested and how often?

Koeppel: “We monitor VOCs and fine particles 24 hours a day. Growers get updates in real time on their phones, so if there’s an issue, they can take action. We work with growers to baseline lab test grapes as soon as we see potential smoke impact. Then we can track the grapes over time to determine the severity of impact.”

DeBlasio: “Testing wine grapes for smoke taint close to harvest is recommended and comparing the smoke’s VOC levels reported to the VOC baseline levels of the same vines from a non-smoke prior season is critical.”

Grapes sealed in a Purfresh Wine-powered, temperature-controlled container unit and treated with ozone for 24 hours.
Photo courtesy of Purfresh Wine

Once smoke taint is discovered, what treatments are available to mitigate the effects?

Koeppel: “We don’t work on the treatments of the grapes, but we can say that when risky wildfire smoke with VOCs are detected, growers can take immediate action by gathering baseline grapes for lab testing. As soon as we identify an effective spray intervention, we will recommend it to growers. If the grapes are close to harvest they can also harvest them, although they would have to make sure their teams have protective equipment and are far from harm. Wildfire threats happen quickly. We don’t know Okanagan personally, but I can say that the grape growers we work with use our technology to manage wildfire risks and protect their harvests. Having that prediction in the field, in real-time, is what really makes a difference.”

DeBlasio: “Smoke-impacted wine is not going away, and winemakers will have many hard decisions ahead of them. Smoke- tainted wine grapes can impact the long-term consumer and price viability of the finished wine across a wine spectrum from no impact to moderate impact, or full crop-loss impact. Specialized ozone (O3) treatment has now been proven to consistently improve the finished wine made from smoke-impacted grapes. To date, we do not know of any other technology that can deliver the improvement consistency that O3 treatments have been providing over the past two years. Winemakers need to know that there is no one silver bullet to 100% correct smoke-impacted wine, but through the use of O3 application to wine grapes, barreling techniques, specialized oak treatments and blending, many winemakers will be able to consistently produce moderate- to high-quality wine for their consumers to enjoy even during the smokey years.

Does this problem affect grape growers exclusively?

Koeppel: “Grape growers are the most impacted by wildfires and smoke taint, but other growers do have to worry as well. Crops like strawberries, blueberries, and even rice could be impacted. For other crops with heartier skins, growers focus on protecting their teams from impending fire threats or keeping their livelihoods safe. Our platform can help them take action and protect their crops.”

DeBlasio: “Smoke taint affects wine grapes more than most fruits because their skins are so critical to the wine-making process, but other fruits may be affected as well. Apples and pears seem to be resistant to smoke taint. The volatile phenols associated with it do not appear aromatically in these fruits. Wild blueberries are also more resistant than grapes.”

Can the problem arise anywhere in the U.S.?

Koeppel: “The changing climate shows that it’s not just a regional problem. Arizona, Colorado, New Mexico, across California, Texas, and the Pacific Northwest are experiencing wildfires, and the susceptible regions continue to grow. Anywhere in the U.S. that experiences drought is at risk. Unfortunately, as the climate changes, that means a wide area in the U.S.”

DeBlasio: “Anywhere that is susceptible to wildfire can be affected, but the U.S. regions most affected at present are California, Oregon, and Washington.