A big rainstorm has hit the West Coast, which has severely slowed wine grape harvest across the Pacific Northwest.
Why, exactly, do wineries worry about precipitation? The reasons are many, as it turns out.
Charlie Hoppes, owner and winemaker for Fidelitas Wines on Washington’s Red Mountain, said the first basic reason is that rain can dilute the sweetness and flavors of the juice in the grapes. Hoppes said he has seen a mild rainstorm drop the sugar – measured in brix – pretty quickly.
Hoppes planned to pick grapes today at Ciel du Cheval Vineyard near his winery on Red Mountain. He will wait until at least Monday and perhaps Tuesday or Wednesday.
“We have to be patient this time of the year,” Hoppes said. “But it’s not even Oct. 1. We still have a lot of time.”
Hoppes said the small amount of rain that fell Friday in the heart of the Columbia Valley – about a 10th of an inch of rain – will help him in the cellar.
“It’s a nice breather,” he said. “We’re swamped right now trying to press off all the Red Mountain fruit that came in six to 10 days ago.”
Hoppes picked grapes early Friday, ahead of the rain.
“If we don’t pick (today) and Sunday, it will give us a nice break.”
Rain little more than inconvenience at Sagemoor
Across the Columbia River at Sagemoor Vineyard, general manager Kent Waliser said rain is mostly an inconvenience.
“It’s a problem for picking because it adds water,” he said.
Waliser said if grapes are picked by hand, workers don’t like getting wet. If the grapes are picked by mechanical harvesters, extra water on the leaves will get in with the fruit.
“It’s not good,” he said. “The winemaker isn’t in control.”
He said rain in the Columbia Valley is typically short-lived and usually followed by windy conditions that help dry the grapes.
“Rain interrupts harvest, but it doesn’t hurt anything,” he said.
Waliser noted that Sagemoor’s vineyards are about 45 percent picked, compared with just 20 percent two years ago during the cool 2011 vintage.
He said the biggest headache from rain is how many of his 70 winery customers might be scheduled to harvest. Arranging transportation from vineyard to winery and other logistics will get messed up in a hurry. Fortunately, he has only one winery on the schedule today – vs. 15 who picked Thursday ahead of the rain.
“That could have been a big problem,” he said. “It would have messed up a whole bunch of folks.”
Winemakers concerned about dilution in grapes
Jessica Munnell, head winemaker at Mercer Estates in Prosser, was on the phone with a grower who was supposed to pick Chardonnay for her today. She decided to hold off for a couple of days.
Munnell said rain not only dilutes sugars and flavors in grapes, but it also can raise the pH (wine grapes have a pH of anywhere from 3 to 4, while water is a neutral 7 pH).
“It will change the chemistry of the fruit,” she said.
Her concern with rain is if warm weather quickly follows, the threat of mildew goes up – especially in white varieties.
“Getting Riesling off before the percentage of rot in vineyards increases – that’s the new game,” Munnell said. “For reds, it’s not an issue because it means letting fruit hang and dry out. For whites, it means getting ahead of the rot.”
Munnell said she will be out in vineyards shaking clusters. If a lot of water comes out, she will know to wait a bit longer.
“If we get a couple of days of dry conditions, we’ll be OK,” she said. “If there’s a lot of water (on the clusters), we’ll let them chill for a little bit.”
Rain slows early harvest in Willamette Valley
In the Willamette Valley of Oregon, the weather system that hit the West Coast looks much worse. Melissa Burr, head winemaker for Stoller Family Estate in the Dundee Hills, said anywhere from 2.5 to 4 inches of rain is expected in the Willamette Valley.
“It’s a sporty vintage,” she said with a chuckle.
About half of Stoller’s vineyard is harvested, she said, but rain could slow things considerably.
“Most of our vineyards are on steep slopes,” she said. “Getting tractors out there is logistically difficult.”
Stoller began picking grapes Sept. 13, which is well ahead of normal – around Sept. 27.
“We still have a month to harvest,” she said. “You can’t judge your whole season on this one event.”
Burr said this is the third rain event since she started picking. Each time has meant waiting a few days for vines to dry out.
“We have opened the canopy on both sides and have good airflow,” she said.
Getting workers to show up when it rains also is a challenge. On Friday, she was expecting a full crew but only six or seven pickers showed up. Fortunately, her vineyard manager was able to pull together more workers and bring in some grapes.
Harvesting between the raindrops is not unusual in the Willamette Valley, Burr said.
“Mother Nature can throw you for a loop,” she said.