Growing & Winemaking


Watching Over the Vineyards

January 2014
by Thomas Ulrich

Karl Wente, vice president of winemaking for Wente Family Estates, has equipped Wente Vineyards with a new generation of electronic tools for tracking growing conditions at the winery’s Livermore, Calif., vineyards. Wente collaborated with AgCode, Enologix, Fruition Sciences, PrecisionAg, Tule Technologies and Wine X Ray to build a network that shaped the information electronic sensors and vineyard and winery teams collected last year into a comprehensive vision for the 2013 vintage.

Like neurons—those wiry cells that fire electrical signals across the peripheral nervous system to the brain and back again—weather stations and sap-flow sensors transmit data to web-based servers. These computers calculate rates, ratios and indices, then send information via the Internet to field or winery crews who can evaluate it from an over-sized monitor, laptop computer, mobile phone or other wireless device.

    In the name of better wine

    Karl Wente admits that all this technology hardly matters unless the vineyard and winery crews make better wines—some bigger and richer, others subtler and more complex. “It’s all in the name of producing the best bottle of wine,” he says.

    The monitor in the production lab reports the vital signs during fermentation and blending, too. Wine X Ray helps members of the winemaking team evaluate phenolics soon after they sample the must or finished wine.

    “With technology to keep track of color, tannin and complex anthocyanins, winemakers can learn more from each vintage,” says Brad Buehler, director of winemaking at Wente Family Estates.

    And with the 2013 growing and harvest seasons behind them, change is already at hand. “We are making wine differently this year,” Buehler says.

    “Instead of pressing to dryness, we are watching tannins to reflect the style of wine we want to make,” explains Andrew Lynch, assistant winemaker for Wente’s small lot winery.

    “With better analytics,” Wente adds, “we can fine-tune fermentation.”


The Fruition Sciences servers, along with the latest vineyard and winery software, transform these rhythmic signals and additional field data into timely information about Livermore Valley weather, grapes, soil and vines.

Together, they are redefining the character of East Bay vineyards.

For the first time last spring, vineyard and winery teams at Wente Family Estates watched the growing season unfold from the 60-inch flat screen monitor that hangs from a wall in the winery’s production lab. There—they assessed the health of the vineyards by analyzing charts and tables that the servers updated as soon as the field crew, software and sensors posted the data.

In addition to reporting evaporative demand, transpiration rates and water deficit indices, the servers culled results from grape, must, tissue, wine and NDVI (Normalized Difference Vegetative Index) analyses for vital signs that deepened the staff’s understanding of how vines grow and grapes ripen. “We’ve created a one-stop-shop for looking at weather conditions, water input, degree days, phenolics, pH, sugars and TA,” Wente says. “This combination of sensors and software allows us to follow trends like fluctuations in sugar concentration within a single vineyard block.”

Programming the remote
Philip Wente, former vice president of viticulture for Wente Family Estates, began collecting field data from a weather station that measured air temperature, precipitation, relative humidity and wind speed nearly 20 years ago. A single weather station could not capture enough data to manage the 1,800 acres of grapevines that line the southern hills and floor of the Livermore Valley.

With several microclimates and soil types to monitor, Karl Wente and senior viticulture manager Rob Sorenson placed weather stations and electronic sensors in a half-dozen vineyards to manage and compare the growing conditions of adjacent vineyard blocks.

Each weather station tracks the microclimate of the vineyard by sampling the atmosphere, then transmitting field data across the network to the servers that relay information to the vineyard and winery teams.

Sorenson can retrieve weather data along with irrigation information, fruit composition and field observations describing the well-being of the vines. In addition to guiding day-to-day field work, the servers calculate a powdery mildew index based on field data and formulas developed by researchers at the University of California, Davis.

Sorenson can review the index from his laptop computer to determine whether the atmosphere is humid enough to favor the growth of powdery mildew and calm enough to spray the vineyard. Alerted to conditions ripe for an outbreak, he can inspect the vines to adjust the interval between applications of fungicide.

While a strong wind can reduce the chance of an infection by drying out the canopy, it can also accelerate evapotranspiration.

Wireless sensors strapped to vines located near four weather stations collect sap-flow rates to help Sorenson and other members of the vineyard team determine how much to irrigate and when.

Thermocouples measure the change in temperature before and after a heater warms the sap. Knowing how much heat is displaced as the sap moves along the cordon, the server calculates how much water is flowing inside each vine.

A slow sap-flow rate with high climatic demand is a sign that the water is moving slowly through the vine, a condition that suggests the plant is not drawing enough water and will experience a water deficit. A fast sap-flow rate is a sign that water is moving quickly through the vine, a condition that can invigorate the plant but delay ripening.

Software and sensors from Tule Technologies complement the data transmitted by the sap-flow sensors. They determine water loss through surface evaporation and plant transpiration by measuring the drying effect of wind eddies on grapevine canopies over a broad area of the vineyard. They report actual evapotranspiration, cumulative and potential water stress permitting Sorenson to compare results with the sap-flow sensors to predict demand.

Irrigation affects the aroma, astringency, balance, body, color, taste and texture of wine. Too little water can reduce yield. Too much water can decrease alcohol, color and pH, while increasing titratable acidity.

From a cell phone or laptop computer, Sorenson can evaluate water demand and soil moisture for a single vine or the entire vineyard, and then replace a shortage with the precise amount of water that the vineyard needs to produce healthy vines.

“I look at the results and base my decisions on immediate information,” Sorenson says. “The technology, though, empowers field supervisors to make decisions on their own, freeing me to concentrate on improving the technology that we’ve already put in place.”

Boots on the ground
Today, vineyard managers tote mobile phones and portable computers, not paper and pen into the fields. Instead of scribbling their observations into daily journals, they tap information onto a mobile device sharing field information with team members in the winery and elsewhere in the vineyards.

Signals travel along electronic pathways accounting for every desktop and mobile computer in the network. Winery and vineyard workers can report or retrieve data and alert one another when they need to share vital information.

Early in the season, vineyard manager Teodoro Simon can report bud break, bloom, veraison or whether leaf hoppers are present. Closer to harvest, he can retrieve the Brix, TA and pH for a specific vineyard block.

Members of the vineyard team collect Cabernet Sauvignon, Malbec, Merlot, Petite Sirah and Petit Verdot grapes from more than 100 Livermore Valley vineyards. The winery team gathers must and wine during fermentation and blending. They send grapes, must and wine to Enologix. Thirty-six hours later, they receive a phenolic profile for each sample.

Enologix provides them with an enological index that rates each varietal based on flavor chemistry and taste, and a style index that compares each sample to benchmark wines from highly regarded appellations.

“The analysis of the grapes shows us the potential of the vineyards,” Elizabeth Kester, lab manager and enologist for Wente Family Estates, says. “By evaluating the grape, must and wine during harvest, fermentation and blending, we can see if we are reaching that potential and modify our fermentation and blending practices to produce the highest quality wines.“

A room with a view
The production lab is part tasting room, part strategic command post. From early spring to late fall, the vineyard and winery teams gather there to oversee the vintage.

The far wall frames the 60-inch monitor that charts the health of the vines. During harvest, a six- or seven-day rolling schedule flows across a whiteboard that covers a wall adjacent to the over-sized screen.

The monitor reports vital signs for each vineyard block throughout the growing and harvest season. On command, for example, graphs and charts reporting daily results or seasonal trends for Brix, pH and TA or total phenols, tannin and anthocyanins appear on the screen.

Members of the vineyard team can review soil and petiole analyses. And, they can evaluate the one variable that they cannot control—the weather. They can consider up-to-date information from weather stations, when they last irrigated a vineyard block and how quickly water is flowing through the vines.

The servers gather data from a variety of sources, compare it and then transmit it to team members along the network. A control panel displays a map of vineyard blocks monitored by sap-flow sensors, for example. Color-coded icons alert the vineyard team of the vines’ condition. The panel contains data fields for sending and receiving text messages and recording and reviewing recently completed vineyard tasks. In addition to alerting members of the vineyard team, the servers analyze the relationship between the composition of the fruit and water status for the vineyard.

For another look at the vineyards, the monitor can display NDVI images representing the photosynthetic capacity of the vines. The technology senses small differences in plant growth from changes in nutrition, leaf area, soil properties and irrigation patterns. It permits vineyard managers to track mulching, mowing, tilling, irrigating, differential harvesting and disease for each sub-block in the vineyard.

Wente, like many winemakers, believes that quality begins in the vineyard. Without the highest quality grapes, he reasons, he cannot produce memorable bottles of wine.

Members of the vineyard team are already managing the vineyards more efficiently.

“We can compare data to determine if we should irrigate three times for four hours or twice for six hours,” Wente says. “We can correlate soil nutrition results from adjacent vineyards to determine which practices are most efficient. And we can explore how nitrogen concentrations in the fields affect nitrogen levels during fermentation.

“Eventually, we’ll know which programs work best.”

Sergio Traverso, Livermore Valley winemaker and co-founder of Murrietta’s Well adds: “It has taken 200 years for prime regions in the Old World to develop a mature understanding of their terroirs, allowing winemakers to produce the best possible wine. With these technologies, we can accomplish that feat for some aspects of grape growing in 6 or 7 years.”

According to Traverso, these changes could launch an era when wines are appreciated for how well a vineyard expresses a personality that distinguishes it from the rest. “As winemakers and vineyard managers,” he says, “we should celebrate differences between regions and varieties by making wine that reflects our terroir, not an industry standard.”


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