Precision harvesting

At Japanese winery Château Mercian they don’t just select by rows – the harvest date includes the picking hour. Increasingly, it’s 2am!


Harvesting at night ensures the grapes are cool

Precision harvesting
  • Chris Boiling
  • 2022-10-27
Château Mercian, one of Japan’s leading wine brands, has taken to harvesting Chardonnay, Sauvignon Blanc and Koshu at night “to create special wines with distinctive aromas”.
The main advantage of a night-time harvest, according to the winemakers, is the cold conditions, which keep the grapes cool and prevent them from deteriorating.
The increasing use of night-time harvests follows a study presented in 2012 which found that the amount of aroma precursors in Château Mercian's grapes tended to increase from midnight to early morning and decrease during the day. Experimentally, it was found that wines made from grapes harvested early in the morning contained more aromatic compounds (3MH) than wines made from grapes harvested during the day.
The winery, part of the giant brewing and pharmaceutical company Kirin Holdings, has been night-harvesting Hokushin Chardonnay since 2010, Mariko Sauvignon Blanc since 2016, and Koshu since 2020.

Mercian harvest
While the Koshu grapes are taken to the group’s Katsunuma Winery in the Yamanashi Prefecture, the Sauvignon Blanc and Chardonnay from the Mariko vineyard go to the adjacent Mariko Winery in Nagano Prefecture (number 53 in the new World’s Best Vineyards list).
There, the Sauvignon Blanc grapes are used to create the special-edition Mariko Sauvignon Blanc Midnight Harvest Barrel Fermented wine.
Winemaker Takenari Kamata outlines the key points of this wine to illustrate how the 'precision harvesting' helps...

1 Zonal selection of the grapes

About 2ha of the vast Mariko Vineyard is Sauvignon Blanc. Half of this is in the northern section and the other half is in the southern section. “Conventionally, we used to separate the northern and southern sections following the advice of Mr Paul Pontallier (ex-Château Margaux),” Takenari explains. Now the grapes are “even more finely divided into rows” based on differences in the soils, vine vigour, sampling analysis data, and differences in taste and aroma profiles. “Detailed zoning is performed for each row,” Takenari says.

2 Selecting the harvest time

This is not just about selecting the day but also the hour. “Determining the harvest period (harvest date) is very important for winemaking, but for Sauvignon Blanc and Chardonnay, we go further than days to harvest (but also) by the hour,” Takenari says. “By harvesting in the middle of the night, when the nutrients produced during the day are fully stored, we aim to harvest the grapes in a fragrant and cool state.”

Mariko Midnight Harvest
From around 2am, the headlights are turned on, and the crops are harvested as quickly as possible.

3 Once harvested, it’s important to vinify the grapes quickly

The harvested grapes are brought to the nearest winery in the group early in the morning and vinified as quickly as possible.
The pressed grapes are barrel-fermented at 20-22℃.

4 Using bâtonnage once a week to add more depth and complexity to the wine

Takenari says: “By bringing the lees into contact with the wine, the ingredients of the lees are transferred to the wine, and the purpose is to give the wine a rich and fuller flavour.”

5 This special wine is sold only at the cellar door

The limited-edition Mariko Sauvignon Blanc Midnight Harvest Barrel Fermented wine is sold exclusively at the winery. Price is about $34 (5,000 yen).

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