Heat Wave Leads to Early Winegrape Harvest in California’s Sonoma County

Ask any winegrape grower to describe the grape harvest in Sonoma County and you typically hear “harvest time is like a marathon.” When it comes to 2017, harvest has taken off like a sprint and the pace shows no sign of letting up until the end of harvest.


August delivered some of the longest, hottest periods seen in years which caused heat stress for both grapes and people. In some American Viticultural Areas (AVAs), it became too hot for too long causing sugars to rapidly increase – in some cases faster than the grapes were maturing.

Some growers increased their irrigation cycles to avoid excessive sun damage to the vine leaves and fruit. Rapid increases in Brix levels resulted in some grapes being harvested as quickly as possible, while in other parts of the county, later varieties were being irrigated to keep the grapes from dehydrating.

The other primary challenge facing Sonoma County winegrape growers is the availability of labor. While there is not a critical shortage this season, it is clear that there is a limited supply with more workers needed, especially in the coming years.

To combat the tight labor market, more growers are turning to mechanical harvesters in addition to using hand harvesting and picking fruit at a riper level. All growers agree that it will only become more difficult to secure the necessary skilled labor force in the future. However, many growers are talking about the increased skill level of the agricultural workers this year.

With early September, for the most part, bringing a much-needed cooldown, the sparkling wine harvest is mostly complete. Throughout Sonoma County, harvest has begun for most varieties of grapes, including ‘Zinfandel,’ ‘Chardonnay,’ ‘Pinot Noir,’ ‘Sauvignon Blanc,’ ‘Viognier,’ ‘Muscat,’ ‘Gewurztraminer,’ and ‘Malbec.’  The harvest of ‘Cabernet Sauvignon’ grapes is expected to begin in earnest in the middle of September. Most growers anticipate harvest being completed in mid-October.

For up-to-the-minute updates on Sonoma County’s harvest activities directly from the growers and wineries, check out Sonoma County Winegrowers’ online Harvest Tracker.