Why are grapes harvested at night?

If you’re out on a Provenςal road at three o’clock in the morning and see bright beams of light cutting through a vineyard, don’t worry. It isn’t someone crushing the vines with a 10-ton John Deere, or a truck attempting a u-turn after missing his turn-off. That diesel roar is coming from a machine harvester; a seriously complicated bit of kit that is designed to manoeuvre delicately through the rows of grapes to harvest them quickly and efficiently. And it isn’t scared of the dark…

Why in the middle of the night, you ask? The answer is simple: Cool fruit means better control over the fermentation process. You’re looking for crispness and aroma – especially important for white wines and rosés.

Daytime temperatures from 30 deg Celcius (and above) can change the sugar composition of grapes and picking at night keeps sugar levels stable due to much lower temperatures. Normally you would have to lower the temperature of the grapes after picking, by running the grapes through a cold bath or a heat exchanger, or big wineries have jackets on their stainless steel tanks, but that all takes a lot of energy.

It is part of a worldwide practice that’s increasingly the norm for harvesting grapes — in the dead of night. It results in better wine, lower energy costs and greater efficiency. Night harvesting got its start as early as 1970 or 1971, when the first mechanical grape harvesters began to be used. Machines can harvest up to 100 times the amount that can be picked by hand. There is a small window of opportunity from 3 a.m. till sunrise and in the interests of speed and consistency there is simply no way to accomplish this by manually picking by hand these days.

Take a look at the video below, where Stephen catches a ride on one of these strange-looking machines.