The dimpling on these wine grapes is from dehydration, which can occur during extended hang time on the vine. Research has shown that for every two degrees above 26 Brix, yield is decreased by 10 percent.
One of the most contentious areas between a wine grape grower and winemaker is grape maturity. Growers want to bring in their fruit before rain, frost, or dehydration can damage quality and reduce yield; winemakers want the fruit to reach optimum ripeness while fitting into the winery’s crush schedule.
In the last 20 years, a major shift in wine grape ripeness has occurred, putting more and more growers and their crops at risk. It used to be that eastern Washington wine grapes were harvested when soluble solids measured as Brix were around 23.5° for red varieties, 22.5° for whites. But now, some winemakers are pushing to the limit for optimum ripeness and flavor and waiting until the Brix level is 26° or higher before picking.
In an effort to help both growers and vintners better understand grape ripeness, the Washington Association of Wine Grape Growers sponsored a half-day seminar in late spring to discuss the physiology of grape maturity, viticultural management practices that can enhance optimum ripening, and harvest decision viewpoints from both sides. The subject evidently resonated with the industry, as more than 120 growers and winemakers attended the meeting in Yakima.
“The problem with ‘what is ripe’ is that ripeness can’t easily be defined,” said Jim Holmes, owner of Ciel du Cheval Vineyard in the Red Mountain appellation. Because there is no one parameter that indicates when grapes are ripe, the definition becomes the winemaker’s vision for the grapes and the desired outcome, Holmes said.
The Benton City grape grower noted that harvest decisions are typically based on key grape berry parameters (Brix, titratable acidity, and pH) that interact with other things like maturity trends, historical experience of the vineyard, and other ripeness variables. These variables include taste, seed lignification, rachis lignification, cluster firmness, berry shrinkage, and pulp character. Holmes said that because it’s difficult to manage all of these factors, winemakers often focus on a specific variable and don’t consider the whole system.
“The danger is that some winemakers wait for some specific they have in mind, and everything else goes to pot,” he said. “Or they use current values instead of looking at trends. In my vineyard, I have really high acids. But I’ve seen winemakers—who are waiting for the acid to drop—get the same acid readings at 20° Brix, 25° and 28°. High acidity is just the character of my vineyard.”
Bob Berthau, head winemaker for Washington State’s largest wine company, Ste. Michelle Wine Estates, said that at Ste. Michelle, ripeness depends on the wine style, varietal, and program the grapes are destined for. With Ste. Michelle’s broad reach (the company makes 50 separate bottlings of wine from more than 20 varieties), Berthau estimated that he is involved in picking decisions representing about 20 percent of the state’s wine grape harvest.
“What I look for in grape ripening really depends on where the grapes are going,” he said. “I can’t have the same picture in my mind when I’m walking blocks and thinking of the wine style from the Indian Wells vineyard as I do when I’m in our home ranch at Canoe Ridge Estate.”
With so many wines made at Ste. Michelle, Berthau notes that he needs distinction and difference for each wine type. Grapes are sourced from different appellations for different wine styles, but he also uses other tools to separate grapes into wine styles, like viticultural practices within a site, timing of harvest, blending, and such.
In determining ripeness, he looks at the numbers—pH, titratable acidity, and Brix—as well as trends of fruit analyses. Vineyard experience, flavors, and seeds and skins are considered.
Berthau also looks at the balance of ripe and unripe fruit in the vineyard. “There’s always variation within a vineyard, but if you can minimize this variation with more uniformity, it makes the picking decision much easier,” he said, adding that there can be a four degree Brix difference between vines within a vineyard. “Without uniformity, you may have to wait until three-quarters of the grapes are on the ripe side.”
Berthau uses some general guidelines for varietals when making picking decisions. For Riesling, he wants Brix to be 21° to 24° and flavor to “break through the acid bag” stage of when the grapes taste like pure acidity. Riesling needs a long hang time with low sugars and low disease pressure. For a variety like Sauvignon Blanc, timing of harvest makes all the difference in the world. “Picked too soon, the wines have thinness. Too long, the desired herbaceous qualities diminish.”
With Merlot, an earlier ripening red variety, if picked in the heat of harvest and grapes ripen too fast, there’s a tendency for the grapes to have aggressive tannins. But with Cabernet Sauvignon, the variety can hang well on the vine, though winemakers must watch for dehydration and keep their eye on the frost forecast. Syrah has a range of wine styles and can be picked earlier for lighter-style, lower-tier wines, and later for high-end wines. For all reds, they want minimum or no vegetal qualities.
Winemakers don’t take harvest decisions lightly. “All of us want to get our fruit in the barn, and we’re getting pressure from all sides,” he said. “But we get even more pressure to produce quality wines with high scores.”
If winemakers make a bad decision, it can have negative impacts on blending. “We all lose if we don’t have quality, scores, and sales,” Berthau concluded.
Communication between grower and winemaker is vital, agreed a panel representing wine grape growers. At Klipsun Vineyards on Red Mountain, vineyard manager Julia Kock sends reports to about 30 winemakers twice a week once grapes reach 19° Brix, so clients can follow trends and track the ripening progress. Most experienced winemakers have already been out to the vineyard twice by mid-May, she noted, but the newer, less experienced ones don’t spend as much time in the vineyard.
“The more interaction with the winemaker, the more likely the winemakers will get what they want,” Kock said.
Chris Banek of Banek Winegrower Services in Walla Walla, said that the grower’s job is to keep vines and grapes in good shape for harvest. With the trend of hanging grapes on the vine longer than in the past, Banek said that water management is key in keeping leaves functioning on the vine and avoiding dehydration. But in the end, he said, “Grapes are ready when the winemaker tells you to pick them.”