Small batches. Made by hand. Artisanal. We have come to associate superior quality with these words, but what if you knew that when it comes to Niagara wines, machines are helping to produce a better product?

We hired an independent research company to evaluate the effect on wine quality when grapes were harvested by machine versus by hand. The results were surprising, but clear.

The majority of cultivated vineyards in Niagara are mechanically harvested. There are still a few old-school hold-outs who rely on manual labour, use horses instead of tractors, and even check in with the cycles of the moon before harvesting, but mechanical harvesters are now used in every premium grape-growing region of the world.

Mechanical harvesters, first introduced in the 1950s, have some clear advantages over hand-harvesting. Manual labour costs about two to three times more than machine harvesting, depending on the variety. Machines can be run at night when the grapes are cooler, preventing browning and oxidization. Most importantly, an entire crop can be harvested at peak ripeness quickly without relying on a limited number of labourers. While the cost of the machines is significant up-front, our clients find that on average, the savings they recover using mechanical labour pays for the machine in the first few years of use.

We know our product is invaluable, but we wanted to see whether we could prove it with some science. We hired independent researchers (KCMS Applied Research and Consulting) to conduct an experiment.

The test subject was Konzelmann Estate Winery in Niagara-on-the-Lake. We harvested 6 lugs of mature Gamay grapevines in one of three ways: by hand; using a grape harvester; and using a grape harvester coupled with an on-board sorting system. The grapes were collected on three separate dates from October to November, 2010. Each lug was individually weighed. The grapes were then processed through a de-stemming machine and the waste from each bin was collected and weighed.

Performance Indicators

We measured the three methods against the following criteria:

  1. The grapes must remain intact. Broken skins start the oxidization process and negatively impact wine quality.
  2. Materials other than grapes (referred to as MOG) such as leaves, petioles, and stems must be minimized. Leaves that are processed with grapes have an especially bad effect on wine quality, imparting a bitter or grassy flavour. Petioles and stems can pierce the grape skin.



The chart shows the number of kilograms of MOG that were removed from each 6-lug sample using the three harvesting methods, on three different dates.article-chart

The amount of leaves comprising the MOG increased from October to November with the two mechanical methods, but not with hand harvesting. As leaves die in the fall, they fall off more easily. Hand-harvesting has an advantage in post-frost weather because fewer leaves enter the samples. Most of the hand-harvested MOG was comprised of rachises (grape stems) that are easily removed during de-stemming, but the total amount of MOG was highest with this method. Hand-harvesting produced the most intact grapes.

The MOG in the two machine-harvested samples was comprised of petioles, leaves, and broken shoots, but there was less MOG than with hand-harvesting. Grape integrity was slightly compromised by both machine methods due to the presence of petioles, but there was very little juice observed when dumping the harvested grapes, indicating that most grapes remained intact.

The clear winner was the harvester coupled with the on-board sorting system, producing very little MOG (0.21%) and preserving grape integrity across the three samples. The sorting system allows wineries to by-pass the de-stemming process, saving time and allowing for a greater volume of fruit to be processed in a short period of time. Although there was a slight decrease in grape integrity, the gains in efficiency and productivity of this system made it the clear winner.