After years of managing the deleterious effects of climate change – drought, wildfires and beyond – winemakers across northern California have experienced much-needed relief in the form of excessive rainfall last winter and into spring 2023.
Potential delays to the 2023 harvest
In Napa, Stu Smith, founder at Smith-Madrone, credited a cold and wet winter, followed by a persistent ‘June gloom’ to this year’s harvest delay, which he predicts to be around three weeks behind average.
Winemaker Paul Hobbs added: ‘Heat units expressed in growing degree days (GDD) year-to-date were down 200-300 degrees by late June, making this one of the coolest growing seasons since Paul Hobbs Winery began keeping records.’
Napa’s Maya Dalla Valle of Dalla Valle Vineyards agrees. ‘We are about three weeks behind compared to last year, and growing degree day wise, we are sitting at 1977 compared to 2294 at this time in 2021, and 2204 in 2018. So this is the coolest year we have seen in quite a few vintages,’ she said.
She noted that by this time in 2022, veraison had already finished, whereas today, it hasn’t even begun for her Cabernet Franc. Elsewhere in Napa, Ehlers Estate winemaker Laura Díaz Muñoz also cited a potential three-week harvest delay.
At Massican, winemaker Dan Petroski described this year’s conditions as similar to pre-2013 days, ‘when we still considered August summer vacation’. Drought and warm conditions of the past 10 years have continued to push harvest earlier and earlier. This year reminds Petroski of what harvest was like seven to 10 years ago.
‘No one can say the last few years were normal. It might be the “new normal”, but this year is feeling like the good old days,’ he said. Petroski added that he is about two weeks behind last year in most instances.
Over in Sonoma, Aperture Cellars’ winemaker Jesse Katz has seen similar conditions. ‘The rain and cold weather pushed back our bud break by about three weeks, and the vines woke up to cool, wet soils and very cool temperatures,’ he said.
Katz described this past spring as one of the coolest on record. ‘The vines were slow to start, but as they developed, our canopies looked very happy, and cluster count looked good,’ he affirmed.
The effects of so much rain
Most northern California winemakers agree that the excessive rains of 2023 have provided much-needed relief to the vines. ‘After several years of severe drought, this winter’s 70 inches of rain was a gift from heaven,’ said Smith, describing a complete groundwater replenishment and the vigorous response to the water.
Hobbs added: ‘The rain refilled most reservoirs and lakes to full capacity and also helped resupply aquifers.’
Dalla Valle shared that due to the replenishing effects of rain, her team had to do very little to no irrigation this year. ‘This, combined with cool weather, has slowed growth and increased canopy vigour,’ she said.
Although most effects of the excessive rain have been positive in northern California, a few small concerns remain. Katz cited having to do a bit more canopy work than in previous years due to the vigour. He also noted a bit of ‘shatter’ due to cool weather during flowering, though he still described the crop load as ‘above average’.
In addition to canopy management, Díaz Muñoz shared that larger canopies and rapid growth have caused some nutrition deficiency in certain vines. However, it’s nothing to be too worried about.
‘This is not exactly a big concern, but it adds an extra layer of vineyard management and yield adjustments this year,’ she said. Díaz Muñoz highlighted that delayed harvest increases the risk of fires, as producers must wait for the right time to pick.
According to all winemakers interviewed, things are looking good across the board. Hobbs noted that temperatures rebounded in July, and canopies look healthy despite overcast conditions during bloom. ‘Nevertheless, veraison is still weeks away as the fruit is still sizing,’ he said.
‘We are now finally seeing some heat, and the vines look incredible,’ said Katz, stating that even with the heat and favourable weather, he still predicts that harvest will begin three weeks later than last year – and go well into October, or even potentially November, should Mother Nature allow it.
Aperture is just starting to see veraison in some of its earlier-ripening Cabernet Sauvignon sites, three weeks behind last year.
Harvest 2023 predictions
Petroski predicts that his picking will begin at the end of August and finish during the first week of October (Massican works with 15 different vineyard sites planted to 12 varieties across Napa, Sonoma and Lodi, hence the varied maturity times).
Although Dalla Valle typically begins during the first two weeks of September, she foresees beginning around 25 September this year (similar to 2018 and 2019).
With regards to quality, the vintage looks bright. ‘I think we are set for a brilliant harvest with a vintage that has more overall acidity and lower sugars than normal,’ said Katz, noting that there is still much more of the season to unfold.
Smith said that despite the set not being uniform, the overall crop load looks good, although potentially lower in some sites due to years of severe drought. Dalla Valle added that although a lot can happen between now and harvest, this year’s conditions thus far remind her most of 2010, a great vintage marked by concentration and balanced acidity.
Hobbs forecasts a fine harvest of typical yields, though seeing as vintage will go well into October, there’s much unpredictability between now and then. ‘Still, as we have seen in other late years, the added hang time and protracted late season ripening often plays to our favour, provided mother nature doesn’t strike with a nasty curveball,’ he said.
Díaz Muñoz concluded, ‘I feel positive about both quantity and quality of the fruit. I can only pray for minimum and short heat events now.’