Does Picking Wine Grapes By Hand vs. Machine Make A Difference?
Erin O'Reilly - Certified Specialist of Wine
Harvest season is a busy time in the vineyard. A coordinated series of decisions between the grower and winery initiates an intense burst of activity - often over a matter of hours. The grapes simply must get to the winery at the pinnacle of ripeness!
How are grapes harvested for wine?
A grower has two options to bring in the crop: hand harvest or machine harvest. Several factors including vineyard site, labor availability, and wine style determine how the grapes get harvested. In some instances, one method must be used over another.
When can you pick using a mechanical harvester?
The grape harvesting machine is called a mechanical harvester. Drive through wine country in the fall and you’ll see what looks like elevated, anemic tractors on thin monster truck wheels driving through the back roads. Mechanical harvesters work in relatively flat vineyard blocks. The trellis system guides the harvesters through the vineyard as they straddle the vines and shake them vigorously. Ripe grapes fall into a basket below, get carried up a conveyor belt, and then deposited into a bin.
Mechanical harvesters can be important to a grower’s success. Harvesters process grapes quickly, and are beneficial if wet, seasonal weather threatens the grape crop. Access to affordable labor can be another challenge in many regions. Take Australia, for example, where wineries employ mechanical harvesters extensively for this very reason. Likewise in the US, rising awareness around social responsibility for providing livable wages and concerns over access to temporary work visas have brought renewed interest to the technology.
Some argue that overall grape quality, and by extension wine quality, suffers with mechanical harvesting. Others say that there’s little difference between premium wines made using either approach. Material other than grapes (MOG for short) can fall into the grape collection bins with the mechanical harvester - leaves, bugs, dead birds that accidentally got stuck in netting, etc. But grapes destined for premium wines will still go through extensive sorting back at the winery, mitigating these concerns.
When do you have to pick wine grapes by hand?
Vineyards located on steep hills cannot be machine harvested. The slope makes it impossible for heavy machinery to maintain a foothold. This is actually a serious consideration when establishing new vineyards. Producers planting on hills must have readily available labor to help with harvest, or their grapes aren’t going to make it to the winery on time. Many older hillside vineyards get abandoned for this very reason.
Some wine styles can also guide decisions around harvest method.
Machine harvesting only removes the berries, not the grape stems. If a winemaker wants to incorporate whole-cluster fermentation by adding full grape clusters, a technique that can increase tannin extraction and complexity, then the grower must hand harvest.
Additionally, for wines that benefit from minimizing oxidation (i.e. exposure to oxygen that can cause browning), hand harvesting is preferred. There’s less chance of broken berries and incidental oxygen exposure between harvest time and pressing. This is true for Champagne, Riesling, and other delicate aromatic white wines.
Producers that aim to craft premium wines may opt for hand harvesting in the vineyard as another layer in the quality control process. Vineyard workers hand-select only the best bunches. An extreme example of this process is the lusciously sweet French dessert wine Sauternes made from grapes affected by Noble Rot, a fungus that concentrates the grape’s sugars and aromas. The French vineyard workers select individual berries within a bunch through successive passes in the vineyard as the grapes ripen. Machines cannot do this.
What’s better? Hand or Mechanical Harvesting?
The question of hand harvesting or mechanical harvesting is a nuanced one, with vineyard owners and wine producers calculating numerous factors all the way back from the initial stages of vineyard planting through to harvest date.
If you ever want to have a lively conversation with a producer, ask them what they think about the topic!
Author Bio: Erin O’Reilly is a Certified Specialist of Wine with the Society of Wine Educators and a long-time lover of all things fermented grape. She pens her work from Monterey wine country where she raises a glass to the growers and producers crafting wines that transcend time.