Posts Tagged: Glenn McGourty

Where there is fire, is there smoke flavor in winegrapes?

 

UPDATED: Viticultural area is Kelsey Bench, not Kelseyville Bench.

UC Cooperative Extension study shows smoke damage to grapes not uniform across vineyards

By the time the Mendocino Complex Fires were officially contained on Oct. 4, 2018, five weeks after igniting, they had burned approximately 450,000 acres in Colusa, Lake, Glenn and Mendocino counties, making it the largest wildfire in California history, according to CalFire.

The fire not only destroyed 280 homes and other buildings, its smoke destroyed the market for wine grapes grown in vineyards near burned areas.

Fearing grapes near the fire would impart smoke flavors to the wine, some wineries rejected all fruit from nearby regions of Lake County and Potter Valley, leaving grape growers to hastily find new destinations for their 2018 crop.

“It can be difficult to determine if fruit has been compromised in quality when exposed to wildfire smoke, and whether or not smoke flavors will result in wine when fermented,” said Glenn McGourty, UC Cooperative Extension advisor in Mendocino County.

A new UC Cooperative Extension study shows wind direction and speed, temperature and a vineyard's proximity to an active fire are factors that can help growers and winemakers predict smoke damage to fruit.

“Fruit in my own vineyard, 60 feet across the street from where the fire started, had no smoke damage because the wind was blowing away from it,” McGourty said. 

$41 million hit to wine grape sales

Due to the Mendocino Complex Fires, an estimated $41 million worth of winegrapes, which would have been sold at full price, were impacted – some were sold at a discount, some were sold to other customers, some were custom crushed, while some were left hanging in the vineyard, according to the Lake County Winegrape Commission and Mendocino County Farm Bureau.

The wine industry needed a scientific method of determining whether grapes could be made into a wine untainted by smoke. With funding from the Lake County Winegrape Commission, McGourty formed a workgroup of local growers and winemakers with Anita Olberholster, UC Cooperative Extension enology specialist in the Department of Viticulture & Enology at UC Davis, to research when fruit quality has been compromised.

“The need for industry standards regarding the impact of wildland smoke on winegrapes and the resulting wines has become even more pressing over the past few years,” said Debra Sommerfield, president of the Lake County Winegrape Commission.

Science showed the intensity, duration and timing of the exposure to wildfire smoke affects the grape's uptake. Generally, the closer to harvest, the greater risk to the fruit. 

“Both the fruit and wine samples in our study showed a wide range of volatile phenol and glycocide concentrations, indicating that smoke damage to fruit was not uniform across the vineyards sampled,” McGourty said.

Volatile phenols and glycosides create off-flavors

Fresh smoke contains volatile phenols and glycosides that can affect fruit, but these chemicals tend to dissipate in the atmosphere in 1 to 2 hours. Vineyards close to actively burning fires and in the path of fresh smoke are most likely to be affected by smoke taint. Smoke that travels long distances is less likely to affect grapes and the wine made from the fruit.

The combination of volatile phenols and glycosides create “smoke taint” – both aromatic and tactile in the mouth. Wine drinkers may smell smoke or other off flavors and experience a drying of their mouth when high concentrations of the chemicals are present in wine.

“At lower concentrations, smoke taint reminds you of brett-affected wines,” Oberholster explained, referring to the yeast brettanomyces. “There is a shortness of fruit, a kind of dryness in the mouth that you know isn't normal. There may be barely perceptible aromas that aren't normal as well.” 

Following wildfire smoke exposure, the researchers sampled fruit from 14 cabernet sauvignon vineyards around the viticultural areas of Lake County, including Upper Lake, High Valley, Big Valley, Kelsey Bench, Red Hills, Lower Lake and Guenoc Valley. As a control, fruit was also sampled from a Napa Valley vineyard that was not exposed to wildfire smoke.   

The scientists took cabernet sauvignon grape samples from each vineyard to a local lab to be analyzed for guaiacol and 4-methyl guaiacol, then made 27 small batches of wine from the samples. The cabernet sauvignon wine samples were sent to the Australian Wine Research Institute, which analyzed the wine for volatile phenols and glycoside compounds. 

“The volatile phenols guaiacol and 4-methyl guaiacol are detected in the fruit by gas chromatography, so it is possible to sample fruit before harvest to make picking decisions,” McGourty said. “Based on our study, berry sampling and guaiacol/ 4-methyl guaiacol analysis are useful for a quick evaluation of whether or not fruit from a particular vineyard may have the presence of volatile phenols that can potentially result in smoke-affected wine.”

Testing the fruit for volatile phenols and glycosides is both expensive and not completely predictive as standards are not well defined for damage based on smoke chemical concentration, he cautioned.

These two compounds aren't the only ones that cause smoke flavors. More than 70 other compounds in forest fire smoke can also produce undesirable flavors and odors described as “like licking an ash tray, burnt garbage, a burnt potato, a campfire that has been drenched with water.”  

The taste test

To assess the levels of the compounds that produce the off-flavors, Oberholster convened a panel of 14 wine industry professionals to taste the sample wines. The wine tasters detected stronger off-flavors in the wines made from riper fruit, which also contained higher concentration of smoke compounds. Less than 6 micrograms per liter of the smoke compounds were difficult for the tasters to detect, leading the researchers to conclude they will have a minimal effect on wine quality. 

Smoke from a distant fire

The scientists also looked at the influence of distance from the fire and elevation on smoke taint. They found some vineyards close to the edge of fires and immediately downwind were heavily affected, with the grapes containing high concentrations of the smoke flavor-causing compounds. But they determined elevation was not a factor in smoke flavors in wines.

Wind direction and speed, temperature and vineyard proximity to active fires are highly likely affect whether there will be smoke damage to the fruit, their research showed. 

“Smoke generated in the first one or two hours from a wildfire is most damaging to nearby vineyards,” McGourty said. “Even though a vineyard may be enveloped in smoke, if the source of the smoke is from a distant fire, it will probably won't seriously damage the fruit quality because most of the volatile gases are gone.”

Lake County Winegrape Commission's Sommerfield said, “Today, the results of this study are already proving to be useful in deepening our understanding of smoke and the risks it poses to grapes and wine, in enabling grape growers and winery buyers to engage in fruitful discussions and make informed decisions, and, in turn, in helping to propel the development of industry standards and protocols.”

To read more about the study by McGourty, Michael I. Jones, Oberholster and Ryan Keiffer, see the January 2020 edition of Wine Business Monthly at https://www.winebusiness.com/wbm.

 “This is a great little study, the first one that I know of that takes a systems approach to evaluating the effects of wildfire smoke,” said McGourty.

 

Glenn McGourty, UCCE viticulture advisor for Mendocino County, describes for Hannah Bird the UC project to analyze the effect of wildfire smoke on winegrapes.

To save cabernet from climate change, UC studies rootstock and clone combinations

UC Cooperative Extension, Beckstoffer Vineyards and Duarte Nursery are launching the wine industry's most ambitious cabernet sauvignon rootstock and clone trial in the Red Hills of Lake County to give the varietal greater resilience to climate change.

Cabernet sauvignon is California's second top-selling varietal by volume, just behind chardonnay.

“We have been growing cabernet sauvignon since the 1970s, and we are very proud to be part of this trial, which will help improve cabernet sauvignon growing for years to come,” said Andy Beckstoffer, owner and CEO of Beckstoffer Vineyards, which is providing the land and labor for the project. 

The industry-driven trial – “Climate-smart Solutions for Cabernet Sauvignon Production” – includes 3,600 vines with 10 cabernet sauvignon clones on 10 rootstocks.

“This trial will give us data that will help inform and improve growing practices for cabernet sauvignon across the state for the next two decades,” said the trial's lead researcher, S. Kaan Kurtural, UC Cooperative Extension viticulture specialist at UC Davis Department of Viticulture and Enology and Oakville Experiment Station.

While the experimental vineyard is in Lake County at a property known as Amber Knolls, the data will be analyzed in Oakville.

The trial officially launched Aug. 15 in Kelseyville with a celebratory vine planting as Andy Beckstoffer and son David Beckstoffer planted the vine that also marked a milestone – the 1.5 millionth vine for Beckstoffer Vineyards Red Hills. Researchers, industry representatives and journalists gathered to celebrate what is affectionately known as “the mother of all cabernet trials.”

“Everything is wonderful in Lake County – for growing cabernet sauvignon and for doing research,” Andy Beckstoffer said, noting the Lake County region's ongoing support for farming. 

Pedro Rubio, Beckstoffer Vineyards Red Hills general manager, said, “Lake County will definitely benefit, but the results from this trial will be very helpful for the whole industry.”

Designed to address resiliency in a changing climate, the trial will examine which combinations give the best results with a focus on drought tolerance and water-use efficiency as well as crop yield and grape quality. 

“The idea behind the trial is to gain further insights into the interactive effects of rootstock selections crossed with cabernet clones and the impact of that on water relations and overall sustainability,” said Clint Nelson, ranch manager for Beckstoffer Vineyards Red Hills.

“The trial will give us an understanding of the synergistic relationship of clone and rootstock and what combination drives the best quality and production,” he said. 

According to Nelson, the trial will look at canopy architecture, yield components, water relations, traditional fruit chemistries, secondary metabolites such as aroma, mouthfeel and color, as well as overall vine performance. 

Duarte Nursery is providing all of the planting material for the trial.

“The diversity of rootstocks and clones chosen for this project includes some of the most modern cabernet sauvignon clones designed for high quality and for production,” said John Duarte, nursery president.

Duarte said the trial is employing a lot of cutting-edge technology and using some of the cleanest plant materials available to prevent grapevine viruses.

“Planting a vineyard with pristine nursery stock initially really extends the life of that vineyard,” Duarte said.

Viticulture has become more data-driven, and this trial will measure a staggering amount of data generated by the 100 or so rootstock-clone combinations over the approximately eight to 10 years of the trial's duration.

“Nothing of this scope has been attempted,” said UC Cooperative Extension specialist Kurtural, who acknowledged logistics as the biggest challenge with planning, data collection and timely analysis being at the forefront of his mind. “It keeps me up at night.”

Planning for the length of the project also is a concern. The vineyard will be planted this year and the first crop will be harvested in 2021. It will take at least six years to begin to see consistent results.

Kurtural said the project will provide research opportunities in academic and applied science for at least two students to complete work toward a doctoral degree in horticulture and agronomy.

Glenn McGourty, UC Cooperative Extension viticulture advisor for Lake and Mendocino counties, is a research collaborator on the project.

“Lake County obviously has an important role to play in fine wine in the North Coast, particularly for cabernet sauvignon,” McGourty said. “And this trial really marks the importance of this location in terms of the commitment and the collaboration that we see here among both public and private sectors.”

 

About Beckstoffer Vineyards: Named “Napa's most powerful grape grower” by both the Wall Street Journal and Wine Spectator, Beckstoffer Vineyards was founded in 1970. Beckstoffer Vineyards is firmly rooted in the soil of Northern California's wine country, with Andy Beckstoffer playing an integral role in the evolution of the wine grape industry since 1970. Joined at the family-owned business by his son David in 1997, they share a common mission – to produce the highest quality grapes in Northern California that form the foundation for exceptional wines – and a combined passion for the land and viticulture expertise. Beckstoffer Vineyards first acquired land in the Red Hills in 1997, which after subsequent acquisitions, today totals nearly 2,000 planted acres across three blocks: Amber Knolls Vineyard, Crimson Ridge Vineyard, and Amber Mountain Vineyard.

About Duarte Nursery: Duarte Nursery, Inc. (DNI) is a family-owned and operated nursery and the largest permanent crops nursery in the United States.

 

UC Cooperative Extension works in local communities to help Californians adapt to climate change

Californians received bleak news last month when the state released its fourth assessment of climate change in California. The report predicts severe wildfires, more frequent and longer droughts, rising sea levels, increased flooding, coastal erosion and extreme heat.

“It's great to be living in a state where science and facts around climate change are valued,” said UC Cooperative Extension specialist Adina Merenlender, “but the recent forecasts may make you want to devour a quart of ice cream in a pool of salty tears.”

Modern civilization has changed the world climate, and even dramatic reductions in global greenhouse gas emissions at this point won't turn back the clock. The warming now predicted by Cal-Adapt is likely already “baked in,” even with our best mitigation efforts, said Igor Lacan, UC Cooperative Extension advisor in the Bay Area of California.

Although the changes can't be reversed, people and communities can take several measures to prevent even greater warming – mostly by reducing the use of fossil fuels – and adapt to the changing environment. In fact, researchers are already helping California adapt to the warmer, more variable and extreme weather expected in the next 100 years.

California has been a leader in facing the future climate head on. The state's first comprehensive assessment on climate change was produced in 2006 under then-Gov. Arnold Schwarzenegger. The second assessment, released in 2009, concluded that adaptation could reduce economic impacts of loss and damage from a changing climate. The third assessment was shaped by a request for more information on the adaptation options in the 2009 report. The fourth assessment was the first effort to break down global climate predictions and their impacts onto specific regions of California.

Author of the North Coast Region Report of the Fourth Assessment, Ted Grantham, praised state leaders for pushing forward efforts to slow climate change and adapt to the new weather conditions expected in California.

“California is playing a unique role in filling the void of leadership on this issue that the federal government was beginning to address under the Obama administration,” Grantham, a UC Cooperative Extension specialist based at UC Berkeley, said.

Across California, UC Cooperative Extension specialists and advisors are working in their local communities to prepare for warming temperatures and adapt to the changing climate. Following are examples of the efforts now underway.

Among the suggested adaptation strategies in the 81-page North Coast Region Report, written by Grantham and his colleagues, the authors encourage government agencies and private forest owners to use prescribed fires and active forest management to reduce an overgrowth of trees and shrubs that fuel the more frequent and intense fires expected in the future.

Although climate change will create conditions conducive to catastrophic wildfire, the reason for dangerous forest overgrowth is related to decades of fire suppression on the landscape.

“Our forests are much denser and have more fuel buildup than they would have under a natural fire regime,” Grantham said. “Mechanical thinning, removing wood from the landscape and prescribed fires can help limit the impacts of wildfire.”

Native American tribes are being tapped to share their traditional ecological knowledge to inform this practice.

“Native Americans have used fire since time immemorial to manage their landscapes,” Grantham said.

Connecting habitats to allow species movement

When climate changes, plant and animal species may find their current habitats no longer fit the environment where they evolved. The fourth assessment technical report, Climate-wise Landscape Connectivity: Why, How and What Next, written by UCCE specialist Adina Merenlender, documented potential techniques to erase barriers to plant and animal movement.

“When we talk about wildlife corridors today, we might view a road as a barrier,” Merenlender said. “With climate change, the movement is over a much longer range for species to find suitable habitat at the end of the century.”

The report says research is needed to compare different approaches to designing climate-wise connectivity, determining how wide corridors need to be, and quantifying the impact of natural and anthropogenic barriers on possible range shifts.

New varieties for California wine industry

California's wine industry is based on international varieties that come from Northern France, where the climate is cool, mild and consistent.

“They really require a cool to warm climate, not a hot climate,” said Glenn McGourty, UCCE viticulture advisor in Mendocino County.

There are many wine grape cultivars from Southern Europe – areas in Italy, Portugal and Spain – that are adapted to heat and make quality wines, but aren't well known. The varieties include Monepulciano, Sagrantino, Periquita and Graciano.

McGourty is studying how these cultivars perform in the warm interior of Mendocino County at the UC Hopland Research and Extension Center.

“We have many options as climates warm in the interior part of California to make wine that needs less amelioration in the winery compared to cultivars from Northern France,” McGourty said.

Recruiting and training climate stewards

The UC California Naturalist Program is moving full steam ahead with a new Climate Stewards Initiative to build engaged communities and functioning ecosystems that are resilient to changing climates.

California Naturalist, with trained volunteers across the state working with myriad conservation organizations, will be using its educational network to improve the public's understanding of climate change and engage the public in community action and local conservation.

“Climate stewards will offer in-person communication with your neighbors, tapping into science,” Merenlender said. “Improving climate literacy is an important outcome, but that won't happen through a website.”

Helping growers modify farming practices due to changing climate

USDA Climate Hub has awarded a grant to UC Cooperative Extension to support tools to assist growers in making strategic decisions in season and long term.

“We have many credible sources of weather and climate data, but often times we are challenged with translating it into decision support tools tailored to growers' needs,” said Tapan Pathak, UCCE specialist in climate change adaptation in agriculture. “It's too early to say which specific tools we will develop, but we are aiming to help farmers use weather and climate information in decision making processes.”

Pathak is also working with colleagues to analyze how generations of navel orangeworm, a significant almond pest, might shift for the entire Central Valley under climate change and how growers can adapt their practices to manage the higher pest pressure.

Using epigenetics to impart drought tolerance

At the UC Kearney Agricultural Research and Extension Center in Parlier and the UC West Side Research and Extension Center in Five Points, sorghum nurseries are being grown under drought and well-watered conditions to compare the environmental impacts on the plants' gene expression.

“We hope to tease out the genetics of drought tolerance in sorghum,” said Jeff Dahlberg, UCCE specialist, who is managing the trials at Kearney. “Using sorghum as a model, we expect this research to help us understand drought tolerance in other crops as well.”

Historically, the genetic manipulation of crops, which has been critical to increasing agricultural productivity, has concentrated on altering the plant's genetic sequence, encoded in its DNA.

Recent studies have shown that environmental stresses – such as drought – can lead to epigenetic changes in a plant's genetic information. Because epigenetic changes occur without altering the underlying DNA sequence, they allow plants to respond to a changing environment more quickly.

Read more about the study.

 

Cities can plant street tree species suited to future climate

Many common street trees now growing in the interior of California are unlikely to persist in the warmer climate expected in 2099, according to research published in the July 2018 issue of the journal Urban Forestry & Urban Greening. (Read the research report here until Sept. 27, 2018)

“Urban foresters in inland cities of California should begin reconsidering their palettes of common street trees to prepare for warmer conditions expected in 2099 due to climate change,” said the study's co-author, Igor Lacan, UC Cooperative Extension environmental horticulture advisor in the Bay Area.

Common trees in Coastal California cities appear to be better suited to withstand the 2099 climate.

“Our research shows that some trees now lining the streets of cities like Fresno, Stockton and Ukiah are likely to perform poorly in 2099,” Lacan said. “Those cities need to look at the conditions – and trees – now found in El Centro, Barstow and Fresno respectively.”

Read more about the study and see a chart that shows cities in 16 California climate zones along with the corresponding cities that approximate their climates in 2099.

Trees to shade California in a warmer future

The changing climate predicted for California – including less rain and higher day and nighttime temperatures – is expected to cause chronic stress on many street tree species that have shaded and beautified urban areas for decades.

Realizing that popular trees may not thrive under the changing conditions, UC Cooperative Extension scientists are partnering with the U.S. Forest Service in a 20-year research study to expand the palette of drought-adapted, climate-ready trees for several of the state's climate zones.

“The idea is to look at available but under-planted, drought-tolerant, structurally sound, pest resistant trees for Southern California that do well in even warmer climates,” said Janet Hartin, UCCE horticulture advisor in San Bernardino County.

Twelve tree species were selected for each climate zone in the comparative study, with several area parks used as control sites.

Read more about this study

Managing the forest for survival in warmer conditions

UC Cooperative Extension scientists are part of a collaborative research project with the University of Nevada, Reno, CAL FIRE and the U.S. Forest Service aimed at developing new strategies to adapt future forests to a range of possible climate change scenarios in the Sierra Nevada.

“It includes the idea that we may be struggling just to keep forests as forests, let alone having the species we value,” said Rob York, manager of UC Berkeley's Blodgett Forest Research Station near Georgetown.

Forests sequester a tremendous amount of carbon. As the climate changes, foresters will need to be proactive to reduce the risk of these massive carbon sinks becoming carbon sources.

“We're working to mitigate predicted impacts to forests, including regeneration failures, drought mortality and catastrophic wildfire,” Ricky Satomi, UCCE natural resources advisor in Shasta County.

At three separate study sites across the Sierra Nevada, novel approaches to forest management are being implemented to develop treatments that scientists believe will increase resilience, resistance and adaptability of Sierra Nevada mixed conifer forests.

The 2018-21 project is led by Sarah Bisbing, forest ecology professor at the University of Nevada, Reno, and funded with $2.7 million from CAL FIRE.

Climate change impacts on vulnerable communities

The latest climate assessment also reports on the serious nature of climate threats to vulnerable communities and tribal communities in California, with a focus on working collaboratively with these communities on research and solutions for resilience.

“The impacts of climate change will not be experienced equally among the population,” Grantham said. “The most significant public health and economic impacts – from flooding, extreme heat, air quality degradation, etc. – will be disproportionately experienced by vulnerable populations, including people of color, the poor and the elderly.”

The assessment includes a Climate Justice Report, which shares the idea that no group of people should disproportionately bear the burden of climate impacts or the costs of mitigation and adaptation. The report suggests collaborating with these communities on research and solutions for resilience.

UC ANR scientists contribute to California’s Fourth Climate Change Assessment

California touts benefits of healthy soils in week-long celebration

On the fifth anniversary of the United Nations' recognition of Dec. 5 as World Soils Day and just in time for the California Department of Food and Agriculture's awarding of $5.23 million in funding to promote the adoption of soil health conservation practices, the California's Healthy Soil Initiative celebrated its first ever California Healthy Soils Week.

For most, that might not sound like a holiday worthy of week-long festivities (a celebration style often reserved for birthdays), but to the passionate folks who've spent the last three years building the nation's leading climate-smart agricultural program, it marks the beginning of a new story of how California agriculture can contribute to feeding the world, saving water and cleaning our air, all while fighting climate change and buffering against its negative effects.

As the inaugural year's theme “Healthy Soils = Healthy Lives” implies, soil health and human health are one and the same. So, in an effort to educate Californians on how vital soil truly is, the week focused on “highlight[ing] all the remarkable gifts healthy soils have to offer,” as CDFA Secretary Karen Ross commented.

From Dec. 4 to 7, CDFA, in partnership with a broad swath of stakeholder groups ranging from state organizations to the private sector (Fibershed, including Community Alliance with Family Farmers, California Farm Bureau, CalCAN, CA Resource Conservation Districts, Roots of Change, and Fibershed, hosted a variety of panels, webinars, and tours to better demonstrate what soil health actually is, what it looks like, how to promote it, as well as barriers to adoption and on-farm challenges.

CDFA kicked off the week by unveiling a series of Healthy Soils Information Panels directly outside Governor Jerry Brown's office. The information panels included an Natural Resources Conservation Service-inspired infographic defining healthy soils as a dynamic interface of the four elements, containing approximately 45 percent minerals, 5 percent organics, 25 percent air, and 25 percent water and teeming with life on the order of 100 million to 1 billion individual bacteria per teaspoon. The next few banners featured the major benefits of healthy soils.  Quite simply: More food. Less water-use. Cleaner air. Healthier planet. The last banner brings it all home with a case-study of all-star farmer, Jesse Sanchez, once honored in Washington, DC as a “Champion of Change.”  

Dec. 5 – the official World Soils Day – was jam packed, starting with a 9 a.m. webcast on Climate Smart Agriculture, followed by a legislative staff briefing led by CDFA Deputy Secretary Jenny Lester Moffitt, and a reception to celebrate the connection between soil and food by indulging in the fruits of California agriculture. The briefing included two discussion panels -- one that featured scientists including UC Cooperative Extension advisors Daniel Munk and Glenn McGourty, East Stanislaus Regional Conservation District agent Jeff Borum and Margaret Smither-Kopperl of the USDA-NRCS Plant Materials Center, and one that featured pioneering farmers, Rory Crowley of Niclaus Nut Company, Michael Crowell of Bar-Vee Dairy, and Bruce Rominger of Rominger Brother's Farms. The growers discussed the benefits and challenges of no-till farming, or conservation agriculture, on their own farms.

The next day turned a bit more hands-on, with California EPA and CalRecycle helping deliver bags of compost, along with educational materials to legislative offices and with tours taking legislators out into the field -- first to the Recology compost facility, and then to Sierra Orchards where some of that compost ends up.

Capping it all off, Southern California got looped into the festivities with a tour of the Urban Farm in Los Angeles and keeping in the urban food systems theme, Sacramento Food Policy Group and ReSoil Sac hosted one last panel and reception at Hot Italian, a local restaurant that sources seasonally fresh, California-grown ingredients and is committed to improving communities and the environment. And it's not just talk, these guys walk the walk with a worm-bin on site to help process their waste into a valuable resource for local growers. 

Throughout the week, the message was clear: the California Healthy Soils Initiative is here to stay. And while it might take an internationally recognized holiday or a statewide weekly celebration to remind us, soils are the foundation of life, of agriculture, and their health is inextricably linked to that of our own. As Rory Crowley of Niclaus Nut company reminded us, “Every day is World Soil Day on the farm.”

 

Read more