The Timing and Chemistry of Harvest

Winemaking is an art that blends craftsmanship with intuition, and the nuanced decisions made throughout the process is what renders each steward so unique. Although fruit and fermentation remain the foundations of the craft, precision and discernment from the artist’s hands play a paramount role in the quality and longevity of what lives in the bottle—all of which trace back to the source, deep in the soils in which the vines flourish. In the closing days of the growing season, winemakers spend countless hours amongst the vines tasting grapes and assessing conditions, ensuring that grapes are plucked from the vine at the perfect moment—and when the pinnacle arrives, the work has only just begun. 

While taking science into consideration, the vast majority of wine professionals agree that the ultimate test of ripeness is taste, and skilled winemakers attune to its perfect state will immediately be able to taste the dynamic interplay of sweetness, acidity, and texture. Beyond the balance between sugar and acidity, the phenolic compounds found in grapes—which come from the skins, stems, and seeds—must also reach optimal ripeness, as these compounds provide the final wines with structure and depth. The key here is harmony: sweetness without bitterness, and enough acidity to balance the wine’s freshness. When picked too early, grapes will boast excessive levels of acidity, which can render the juice sharp and austere. On the contrary, when fruit is left too long on the vine, the opposite occurs; acidity quickly drops, rendering the juice flat and dense. 

In addition to pests, some winemakers have also taken to unique solutions to do their best to keep damaging weather at bay. One of these means is through the use of hail cannons. “Hail cannons are used to try to stop the formation of hail during a rain shower in a storm, explains Elyse Lovenworth, head sommelier at Sommsation. Lovenworth notes that when strong storm systems are in the forecast, hail cannons are deployed an hour to 30 minutes prior to the storm to attempt to shake off excess water accumulations so that they don’t freeze and become hail—which can ruin an entire vintage in one fell swoop.

Although viticultural decisions surrounding pruning and soil management play a role in ripeness, its foundations are rooted in climate conditions. The sun’s warmth on the grapes is the strongest factor in ripening, and is greatly influenced by a vineyard's precise location and aspect. Southern-facing vineyards in the Northern Hemisphere will benefit from the most direct sunlight—especially when planted along staggering slopes—whereas the opposite rings true for vineyards south of the Equator.

Dramatic climate conditions have brought additional factors into winemakers’ picking decisions. Excessive rainfall, heatwaves, hail, and frost, can all influence picking time—or even destroy a harvest in the blink of an eye. Regions such as Burgundy and Willamette have been greatly affected by late-season frosts, which can halt a vine’s ability to produce fruit in a given year if experienced after budbreak. Similarly, prolonged periods of drought and wildfires, similar to those experienced by northern California in recent years, can also end a vintage in the blink of an eye. 

 Using a selection of clones versus one singular clone aids against disease pressure, meaning that one negatively affected cluster doesn’t necessarily mean the loss of a whole crop. “Clonal melange, as it is sometimes referred to, helps create complexity in wine in the vineyard,” Lovenworth affirms, stating that each clone has distinctive characteristics that contribute to a wine’s final flavor profile, as well as dictates how it operates in a vineyard.

While the art of winemaking is steeped in tradition, chemistry and technological advances have also shaped the way in which vinification is done today. The modernization of machinery, measuring tools, and means of collecting information have provided winemakers with a myriad of ways in which to execute their craft—meaning that no two stewards, nor the wines produced at their hands, are the same. For wine collectors, there’s no more exciting time to enjoy the fruits of their labor than the present.

Though numbers and statistics only tell part of the story. Taste and expertise—which ultimately come with diligence and time spent in the cellar—coupled with personal preference and stylistic choices, are ultimately the deciding factors that guide most winemakers to craft the best wines possible, as well as create long-lived bottles that tell their vineyards’ stories best. For wine collectors, there’s no more exciting time to enjoy the fruits of their labor than the present.

In the end, winemaking reflects a choreography between nature, science, and craftsmanship. Because there is no determinative algorithm for success, the best winemakers complement their experience-based intuition with nuanced understanding of the chemistry involved to achieve transformative alchemy. Great winemakers, like great chefs, commune with their senses—taste, touch, sight–—while navigating the cognitive complexities of each harvest. Yet in both crafts, the goal remains the same: to elevate something simple into something sublime, and above all, to create a harmonious final product that reflects its unique time and place, and that confers on partakers the transitory ability to transcend everyday experience.