BY KATHLEEN WILLCOX
Low-yielding vines might sound appealing to those who associate scarcity with desirability, but less isn’t always more in wine. Increasingly, scientists and winemakers say that each vineyard should be evaluated by its own range of attributes. These factors contribute to its ability to support low- or high-yielding grapevines.
French Roots
The idea that low-yielding wines are better can be traced as far as Roman poet Virgil. The notion is written into French Appellation d’Origine Contrôlée laws, where yields are measured in terms of weight per acre.
In Bourgogne, for example, each appellation has different “maximum-base yield,” rules that can be adjusted up to 20%, if climatic conditions call for it.
Base yields in grand cru reds are 35-37 hectoliter (hl) per hectare (ha; approximately 2.471 acres); grand cru whites are 40-64 hl/ha; premier cru reds are 40-45 hl/ha; premier cru whites 45-68 hl/ha; village appellation reds 40-45 hl/ha; village appellation whites 45-47 hl/ha.
For consumers, the price difference between a village appellation red and a grand cru is often several hundred dollars.
“This is one of the most highly contentious misunderstandings that, until very recently, hasn’t been debunked by winemakers,” says Keith Wallace, the founder, winemaker and sommelier of the Wine School of Philadelphia. “It’s a case of there being a little truth to it, especially in places like Burgundy and Priorat, where the soils are poor and the pH is way too high or low. In those cases, low-yield growing methods make sense, but it became a kind of cult that was applied in completely different terroirs across the world.”
The idea that less fruit would lead to tastier, more focused wine seems to make sense on an instinctive level, and thinning fruit to reduce yield became a standard farming practice across the world. Well-respected oenology programs taught students that it was the best route to great wine.
“When I was at [University of California-Davis] in the late ’90s, all of the teachers preached the gospel of low yield, but that is absolutely not the case anymore,” says Wallace. In Napa, where a lot of UC-Davis grads find careers, “the soil is fertile, and you need more tonnage per acre for them to achieve full ripeness. In the early [2000s], there was a real movement among winemakers and winery owners to push back.”
California Reboot
Soil types, growing conditions, elevation and the grape varieties being grown can change a winery’s calculations, says Dan Petroski, winemaker at Massican Winery, who also served as winemaker at Napa’s Larkmead Vineyards for over 14 years.
“There was definitely a shift in California away from the low-yield philosophy,” says Petroski. “There used to be almost a formula to make a wine rated 95 or above by Robert Parker. You’d hire Heidi Barrett as a consultant, and you’d definitely want less than three tons an acre. In Robert Benson’s Great Winemakers of California, published in the late ’70s, all of the greats-Paul Draper of Monte Bello and Ridge, and Joe Heitz-talked about how important low-yield is.”
Even now, he says that in every contract between grower, there are clauses on sugar and yield. But as climate change accelerates, Petroski sees that changing.
“It’s really finding the balance between quality, flavor and yield, and it’s getting more complex,” he says. “The summers here don’t end until Thanksgiving, and the heat spikes later in the growing season can dehydrate the grapes too quickly. If grapes close to harvest lose 15% of their weight suddenly, the yield will be way down, but so will the quality. We can artificially rehydrate those grapes, but that can lead to diluted flavors.”
In 2020, while at Larkmead, Petroski experimented with grape thinning.
“We took one block and gave half [of them] two grape clusters per shoot, and another just one [cluster], thinking that the one-cluster grapes would produce more intense color, sugar levels and flavors,” says Petroski. “We stopped irrigation after veraison [the onset of ripening in grapes]. But the vines just seemed to acclimatize to the long and extreme heat of the year, and the lower-yield block wasn’t that different from the higher-yield block.”
The vineyard team found that it was better to simply put up shade cloth around the grapes. About 90 of Larkmead’s 110 acres get shade cloth, and the team found the system produces results expected of low-yielding vines: greater concentration, balance and complexity.
Finding the Balance
At La Rioja Alta, Winemaker Julio Saenz says the producer’s approach to farming the same grapes differs between Rioja and Ribera del Duero.
“We have different yield goals, depending on the terroir,” says Saenz. “For Garnacha in Rioja, you need a much lower yield for high-quality wines. But in Ribera del Duero, with different soils, elevations and weather conditions, our production levels can be much higher.”
If the goal is good wine, Saenz says, each vineyard’s terroir and grape variety must be considered.
Jesse Katz, founder and winemaker of Aperture Cellars, believes that some sites require lower yields to make truly great wines, but he argues it’s just as often not the case.
“[On sites] where the soils have a hard time drying and richer-nutrient soils, a much larger vine and canopy will be created,” says Katz. “This site will often make better wine if you hang more fruit per vine to help the vine put more energy. In this case, higher yields may actually mean higher-quality wines.”
In the end, you just have to know the vineyard, experiment and base your farming philosophy on evidence, not hearsay, says Petroski. “Low yield is not a silver bullet. Just ask Larry Hyde, who makes the best Chardonnay on the North Coast, and gets maybe five tons an acre, whereas others right around him get three.”
And don’t necessarily believe the hype if the next bottle of wine you grab touts its low-yielding vineyards. Similar to terms like “sustainable,” or “clean,” there are no laws that regulate its use. “Low yield” is often deployed as a marketing term.
“Unfortunately, a lot of winemakers still talk about having low-yield vines, even though they know it’s meaningless,” says Wallace. “Sommeliers and wine marketers just haven’t caught on to the idea that it doesn’t matter in every region. And most wine consumers just accept it as fact.”