Growers Left High & Dry

Growers Left  High & Dry

For years, some California winegrape growers have complained that wineries — who hold all the cards when it comes to their contracts with growers — made them hang their grapes on the vine too long in the pursuit of more intensely flavored wines. “Growers have suffered unnecessarily because of hang time,” says Nat DiBuduo, president of Allied Grape Growers, a cooperative of 500-plus growers. “The wineries would schedule the harvest late; they would just keep holding the growers off, saying that they were waiting until grapes lost their vegetative flavors.”

The growers didn’t like this because most of those contracts called for them to be paid on a tonnage basis, and the longer the grapes would hang past what the growers considered ripe, the more water weight they would lose. If the growers thought they were really producing better fruit, it would have made some sense, but DiBuduo said it did not. “Obviously there’s going to be some raisining,” he says. “You can taste the change when you eat the fresh fruit, so of course you’re going to change the wine quality.”

The issue really got contentious in the late 2000s when growers began to learn that the grapes were so dry that the wineries had difficulty crushing them, to the point that the winemakers had to add water. How could the growers not suspect they were being taken advantage of, says DiBuduo, when the moisture was essentially removed and then replaced. “How is that good for the wine?” he says. “Replacing the natural water to get it through the crusher and destemmer doesn’t make sense.”

No Long-Term Damage Found
A half-dozen years ago, when the controversial issue of extended hang time bubbled over, winegrape growers were concerned that by waiting to harvest grapes past what they considered the optimum time, their vines might be sustaining damage.

The issue came to a head following the relatively small California harvest of 2004, when with overall tonnage already down, growers saw tonnage fall further because of wineries’ mandating increased hang time. The then-president of the California Association of Winegrape Growers, Karen Ross, said it wasn’t fair that in their contracts with wineries structured on a tonnage basis, growers were taking all the risks. Ross, who now heads up the state’s Department of Food and Agriculture, also said growers had concerns about their vineyards’ future.

“Do we really know what (increased hang time) is doing to the long-term health of the vineyard?” she said at the time. “Do we really understand the whole picture regarding the ramifications of what we’re doing?”

Today, Sanliang Gu’s research team has found extended hang time has no impact on the long-term health of the vineyard, at least in warm growing regions. “We’ve never seen a negative effect,” he says, “even on the vineyards we never harvested.”

Gu believes that there were other factors at work in the vineyards of those growers who have seen negative impacts on their vines. In an attempt to produce high-end wines with intense flavors, many growers, especially those in cooler areas such as Napa and Sonoma, stress the vines. “If you’re water-stressing them, that’s a different story, and I suspect that’s what’s happening,” he says. “I don’t believe hang time is as stressful as water stress or nutrient stress.”

He emphasizes that his research was done only in the warm weather growing area of the San Joaquin Valley, and not only was he growing the grapes under “normal” conditions — with no water stress — the region has a longer growing season than cooler areas. That could be a factor in that the vines have more time to recover following harvest. However, as he notes, even the unharvested vines recovered nicely.

Gu believes the vines’ health isn’t adversely affected for the same reason that increased hang time doesn’t produce better wines in warmer climes. “The plants stop sending sugar to the fruit after it reaches 25 Brix,” he says, “so they probably wouldn’t be stressed.”

“Toasting” Raisins

A few years ago, Sanliang Gu, who holds the Ricchiuti Chair of Viticulture Research at California State University-Fresno’s Viticulture and Enology Research Center, got to wondering about this issue, too. He led a research study (See “Research Conclusions At-A-Glance”) into hang time, and sure enough, DiBuduo and his fellow growers were right. However, Gu is quick to note that all his group’s research was done at vineyards in the Fresno area, under very warm growing conditions. That’s part of the reason so much fruit is produced in the Fresno region — tellingly, the Raisin Capital of the World is in nearby Selma — and in fact about two-thirds of the state’s winegrapes are grown in warm weather climates.

Gu found that the growers were absolutely right in their contention that 25 Brix was the upper limit for accumulating sugar. Wineries were calling for 28 to 30 Brix, mandating the fruit hang into fall, but they were only getting it because of dehydration, he says. “There’s a reason why the raisin growers have their fruit out then,” he says. “We’re not just hanging fruit on the vine, we are toasting it.”

Gu is quick to add he’s not a wine expert, and his conclusions are based on fruit quality. He notes that at that same time, in late September, it begins to cool in other growing areas of the state, such as Napa and Sonoma. “Hanging fruit on the vine in cooler regions is totally different,” he emphasizes.

Less Color, Mouthfeel

But in warm weather regions, besides dehydration, hang time can cause other fruit quality problems, he found. For example, pH is dramatically increased. He found the pH of grapes harvested in late September as well as early October could be 4.0 or greater, and above 3.8, vintners can actually have trouble making wine. “The wine gets unstable and bacteria can start to grow, which will of course ruin the wine,” he explains. “That’s what stopped a lot of winemakers from demanding hang time.”

Two other desirable components were decreased through increased hang time: anthocyanins and tannins. Anthocyanins give red wine its color, and perhaps it comes as no surprise, but the level of extractable tannins dropped to near zero as the fruit began to raisin. As for tannins, the optimal temperature for formation is 75°F, well below the temperatures found in the southern San Joaquin Valley on an average September day. Tannins give wine mouthfeel, the quality that make people refer to a wine as a “big” Cabernet Sauvignon. “It’s hard to get enough tannins in the valley, because the high temperatures ‘burn’ the tannins out of the grapes,” says Gu. “Increasing heat through hang time actually reduces tannins.”

As for DiBuduo, who serves on American/Western Fruit Grower’s Editorial Advisory Board, he says the hang time problem has lessened in the past couple years because consumers have been turning away from those more intense, high-alcohol wines. He’s obviously happy that Gu’s research cleared up the issue, though, and highlights its value. “Dr. Gu’s research has given us a leg to stand on. It’s like ‘Hey, we told you so.’ This shows the value of research on cultural practices so we can improve the quality of our fruit,” he says. “We need to support the American Vineyard Foundation and the National Grape and Wine Initiative, because winegrape growers in general are not funding enough research for our future.”

Research Conclusions At-A-Glance

Here are the conclusions of a study led by California State University Fresno Professor Sanliang Gu titled “Influence of Berry Hydration on Berry Fresh Weight and Fruit Composition During Hang Time in Cabernet Sauvignon Grapes in a Warmer Region.” Note: the study’s co-authors were Yulin Fang, Guoqiang Du, Erik Mallea, Sean Jacobs, and Robert Wample.

- Berries without visual shriveling had similar weight and composition regardless of hang time, irrigation, and cluster location in the canopy.

- Shriveling berries had higher Brix, TA, and pH but reduced fruit fresh weight.

- Shriveling berries had much lower model wine extractable anthocyanins, phenolics, and tannins.

- Berry shriveling was associated with a greater number of dead pedicels.

- Berry shriveling associated with longer hang time reduced yield and fruit quality in warm regions.

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