Unusually warm weather made for an early start to the wine grape harvest in the Pacific Northwest and Northern California, and continued cool nights should assure quality is top notch, a research climatologist said.
Gregory Jones, a professor at Southern Oregon University who tracks the industry and specializes in how climate variability affects vine growth and wine production, said many growers are reporting the earliest harvest since 1992, or the earliest harvest ever at their vineyards.
Early ripening and sparkling wine varieties were the first picked, Jones said in an email newsletter he circulates to about 3,000 subscribers in the West.
“All other varieties are lining up for harvest but the recent shift to cool nights will allow for some timely queuing for flavors to develop,” Jones said in his Sept. 5 newsletter.
The unusually hot summer, of course, is the reason for an early harvest.
Average temperatures for August were one to four degrees above normal in California, Oregon, Washington and Idaho, Jones reported.
The increase in degree-day accumulation — the combination of heat and time required to complete a plant’s growth — was even more striking, especially in Oregon and Washington, Jones said.
Degree-day accumulation in both states as of Sept. 1 was 10 to 15 percent above 2014, another hot summer, and 30 to 35 percent higher than 1981 to 2010 averages, he said.
The arrival of cooler nights, if the pattern holds, can put a good finish on what appears to be another good grape crop.
“There are two things that help plants to start ripening, especially wine grapes,” Jones said. “Shorter days, and cool nights. That is an environmental cue to tell the plant, ‘We have to ripen this fall.’ ”
The same thing happens with tomatoes, which take on a deep red color as summer ebbs, he said.
“Those cooler nights tell them to do this soon or you’re not going to ripen,” Jones said.
Jones said vineyard managers face day to day harvest decisions in such conditions. “How long do they leave fruit out there to get the different flavors they want?” he said.
Jones agreed Oregon growers are optimistic at harvest time no matter the conditions.
“It’s kind of like in Bordeau, in France,” he said with a laugh. “It’s always the vintage of the century.”