For thousands of years cultures around the world have celebrated the summer bounty as the days begin to get shorter and the weather cooler. Elaborate rituals, special songs, and large meals signal the harvest of the traditional local staple crop. Wheat and rice, responsible for feeding much of the world’s population, are both sown in September and October, as are many perennial crops. Although wine may provide a different kind of sustenance, the end of a growing season in the vineyard is a special time as well.  

Some grape varieties ripen earlier than others, and there are numerous other factors, such as the vineyard location, soil type, and slope, that all play a role in determining when the grapes will be ready. Grapes destined for sparkling wine are picked first, as lower sugar levels are actually preferred for them. White grapes come next, with Sauvignon Blanc commonly picked earlier during the harvest so as to maximize freshness. Reds will follow, with Pinot Noir being picked before more robust grapes with thicker skins, such as Cabernet Sauvignon. In California, the harvest season usually starts in early to mid August and continues into October.

Towards the end of summer the grapevine will begin to use photosynthesis to create more and more sugar in each grape. The color of the grapes will change, most noticeably in red wine grapes whose skins change from green to red during this time. The French call this process veraison. As sugar accumulates in the grapes, the acid level falls. Compounds in the grape’s skin, stem, and seed also ripen around this time and are an important factor as these compounds provide flavor in the wine and can lead to bitterness if not fully ripe. These changes are known as phenolic ripeness or physiological ripeness. The goal is to pick the grape when sugar ripeness, physiological ripeness, and acidity are all in balance. Not all grapes in a bunch ripen at the same speed. Zinfandel is an example of a grape variety that ripens very unevenly; both underripe grapes and raisins will be found on the same grape cluster. This is the reason that Zinfandel will have a flavor profile that includes fresh strawberry notes, but also fig and prune notes.

A cool, dry end to the growing season is considered ideal for bringing in grapes that are fully ripe while retaining the acidity needed to make a fresh, balanced wine. Mother Nature doesn’t always cooperate, however, and vintners must sometimes pick earlier than they would like in order to avoid incoming storms that can dilute the grape’s flavors. If it does rain just before harvest, the winemaker might wait to pick the grapes, hoping they will dry out without rotting.

Winemakers’ opinions on what constitutes peak ripeness vary widely. There are tools to measure the sugar content of grapes, but hands-on winemakers often determine when to pick by walking through the vineyard, tasting grapes as they go. Some winemakers aim for grapes that will produce a ripe, lush fruit profile in the finished wine and will wait as long as possible to schedule the pick date, whereas other winemakers aiming for a brighter, more fragrant profile will choose to pick the vineyard earlier in the season. Winemakers purchasing fruit from a vineyard owner often have some say in when their particular section will be harvested, with rows for one winemaker sometimes being picked several days earlier than rows for another winemaker.

There are two main methods for getting the grape bunches off the vine and on their way to the winery. The first, hand harvesting, entails physically cutting the cluster off using either a knife or clippers. Machine harvesting, developed in the 1960s, usually involves a tractor straddling the row of vines, deploying rubber or fiberglass rods to shake the ripe bunches into attached bins. There are advantages and disadvantages to both methods.

Hand harvesting is much more expensive, and with a tightening of immigration laws and the rise of the cannabis industry, which also harvests in the fall, procuring a skilled labor force has become increasingly difficult for many vineyard owners. When asked for his thoughts on the upcoming harvest, William Allen of Two Shepherds replied that he’s “Hoping we don’t have as much of a labor shortage for picking crews as we did in 2018.” Even with highly experienced workers, hand harvesting takes significantly longer, which can be a problem if multiple vineyards ripen at the same time or poor weather is in the forecast. However, picking by hand is a gentler process and winemakers looking to achieve certain styles of wine often insist on intact grape berries. Hand harvesting also provides more exacting selectivity because trained workers can leave fruit that isn’t up to standards on the ground rather than allowing it to make its way into the bin. Some vineyards are on slopes that are too steep or have vines planted in ways that don’t allow for a tractor to be used. Working these vineyards by hand is arduous, but necessary. In Europe, some wine-growing regions mandate that grapes are picked by hand.

Machine harvesting is highly efficient, and with new advances in technology it is now preferred by some renowned winemakers. MOG, or Material Other than Grapes, making its way into the bins was always a major concern, but today’s growers can attach destemmers and optical sorting equipment to root out leaves, bugs, and even grapes that just don’t look right. The upfront investment is large, but the flexibility to pick whenever you want and the labor savings in the long run are leading more high-end operations to adopt machines for harvesting.

Harvest time in a wine-growing region is truly a spectacle. Harvesting often begins in the wee hours of the morning. Picking grapes at very cool temperatures wards off oxidation, helping to ensure fresh, fruity flavors in the resulting wine. Three o’clock AM is a popular time of day to begin harvesting a vineyard, so large, portable lights must be brought in if a crew is to pick the vineyard by hand. Depending on the quality of wine, some sorting usually occurs in the vineyard when either a worker or machine discards certain grapes or bunches that are undesirable in some way. Ideally, grapes that are sunburned, rotten, underripe, or overripe are excluded.  

The full bins can now head to the winery, which may be several hundred feet or several hundred miles away. Most wines are not made at the location of the vineyard. Trucks crisscross the wine region each morning, moving grapes from vineyard to winery before the sun’s heat takes hold. Even many prominent Napa Valley wineries, surrounded by their own manicured vineyards, still purchase fruit from other sources to supplement their own production. Young winemakers often start out by renting space at a winery and purchasing all of the fruit they need because the high cost of buying land makes owning a vineyard right off the bat impossible.  

Once at the winery, the fruit must be processed in a specific way to facilitate the style of wine that the winemaker intends to produce. Figuring out where to temporarily store a particular lot of grapes can be a challenge for a winemaker. It isn’t uncommon for a winery to produce a dozen or more individual wines each year. Some of these are often blends that will include one grape variety harvested on one day, such as Merlot, and another grape variety, such as Cabernet Sauvignon, that is generally picked a couple of weeks later. Many wineries receive dozens or even hundreds of grape deliveries over the course of a two-month period.

For very high-end wines, a vibrating sorting table will be used when the grapes arrive at the winery. Workers remove grapes that don’t meet the standards as they rumble down the line. From here, the winemaker must decide whether to crush the grapes, press them, or leave them whole, depending on the wine style they are trying to achieve. Winemakers also decide whether the grapes will ferment in stainless steel, oak, plastic, or a concrete vessel. They can also decide whether to inoculate with a commercial yeast or allow an ambient yeast to start fermentation. Once fermentation has begun, it usually lasts for a few weeks, but this is not downtime. Even winemakers with a hands-off approach will need to continually check the wines for problems arising from the fermenting process, such as the development of certain bacteria that can produce off-flavors. They will also perform daily maintenance to help the fermenting vats progress towards the desired profile in mind for the finished wine, such as introducing or restricting oxygen or warming or chilling the vessel. 

In general, red wines are fermented with the skins included in the juice, but white grapes have their skins removed. Since fermentation produces CO2, the red grape skins, or the cap, rises to the surface and the winemaker must punch it down or pump the juice back over it in order to reincorporate it. All of this is very labor-intensive and may require the help of many employees or interns, depending on how much wine is being made. After each piece of equipment is used, it must be cleaned and sanitized to prevent the spread of potentially harmful bacteria. During the harvest, winemakers and their staff will work fifteen or sixteen hours a day, six or seven days a week. Most of this time is, in fact, spent cleaning, rather than making anything. Keeping up with the physical labor of sorting fruit, operating grape presses and crushers, and monitoring fermentation is incredibly demanding. Good organizational and recordkeeping skills are critical as well. Advanced forklift skills are essential. Markus Niggli, owner and winemaker at Markus Wine Co. in Lodi explained that harvest “is when you are not ready to receive the first batch of grapes – when you have to find the rhythm for the next 8-10 weeks, when you say good bye to your family, when your wife will complain that she has to hang a poster up at home to remember you.” And “when the beer tastes the best after a solid 12 hour shift out in the field.”

I once spent a week in the Priorat region of Spain during harvest. The work in the vineyards was backbreaking and the cellar was a cold and damp place when we began the workday each morning at 5:30 AM to “punch down” the fermenting tanks. The people were so welcoming, however, that it made the work not only bearable, but really fun. While I was there, several wineries in the village set up celebratory lunches with their teams in front of their cellars at the conclusion of production, The winemaker I was working with likes to pick his vineyards as late as possible, so our luncheon was held last. Even after just a week, the sense of camaraderie and accomplishment among the team members was immense, something I will never forget. From my experience, I will always have the greatest respect for all those involved in each year’s harvest. Whether they are picking grapes, driving a tractor, or rinsing hoses, these people give up both sleep and time with their loved ones for almost two months each year so that we can enjoy delicious wine.