LIVERMORE -- California's historic drought that has ravaged the entire state has had little effect on this year's Livermore Valley wine harvest, but vintners are counting on a wet winter to stave off potential disaster next year.

"It should be noted that just because we made it through this year's harvest, that doesn't mean there's not a serious crisis on our hands," said Aaron Taylor, operations manager for Livermore's Retzlaff Vineyards and Estate Winery. "Last winter was the driest or second driest on record. If that happens again, there will have to be a rearrangement of how we think about water in this state."

The 50 wineries and more than 30 vineyards in the Livermore Valley wine region came through the record-breaking drought relatively unscathed this year. This year's harvest is yielding slightly fewer grapes, but other weather variations have helped to produce high-quality grapes.

"We've benefited by high humidity," said winemaker John Kinney, owner of Livermore's Occasio Winery. "The humidity has been running about 20 percent higher than normal for much of the summer, so it's cut down on water loss in the berries. It helps conserve water, but it also helps with the berry ripening process."

The mild overnight temperatures the area has experienced this summer also boosted the ripening process.


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"The nighttime temps have remained particularly warm," Kinney noted. "Because we've had warmer nights, the grapes continue to ripen during the evening. Our harvest this year is two weeks earlier than it was last year. The quality of the fruits has been stunning. This could be a year for making wonderfully beautiful and balanced wines without too much alcohol."

The grape harvest at The Steven Kent Winery outside Livermore is down by as much as 30 percent compared to last year but is still above average because 2013 was a bumper crop.

"We have an awful lot of juice coming out of the grapes right now," said Steven Mirassou, owner and winemaker at Steven Kent. "I see some cabernet that has some smaller berries mixed in with the bigger berries. That's not a problem with cabernet because we don't want real big berries. We want smaller berries, so from a quality standpoint, (the drought) might be helping us a little bit."

Since vineyards have been forced to cut back their water use, it has led them to use the limited water supply in different ways.

"Everybody in Livermore is under 25 percent reduction, so we won't have 100 percent of the water we expected to have," Mirassou said. "That will mean shorter watering times. It could mean you're saving your water for your most important fruit. We have to be more cognizant of how the vineyard is doing, which blocks have the most potential and managing our water with a fine-toothed comb."

Retzlaff has cut back on water "by careful management of timing the number of watering cycles and how long we water," Taylor said. "We started with more diligent control of the weeds. They suck up a lot of water. By controlling weeds, we can reduce water usage."

The biggest problem is that as water supplies dwindle, the quality of the remaining water is compromised.

"Where we're seeing drought issues is with water quality," Mirassou said. "As water levels go down, you get more dissolved solids in the water, and it becomes more alkaline with a higher pH. It can burn leaves, which we're seeing. You get these brown leaves that would be typical of winter, but we're getting them now."

Fewer healthy, green leaves "drop the photosynthetic potential of the vineyard," he added, and the fruit doesn't ripen.

"If you have a bunch of leaves that were green and performing photosynthesis, then you've lost the sugar production engine (if they're brown)."

The vintners agreed that the real test for their vineyards will be with an enduring drought.

"We're over the hump as far as being seriously concerned about water," Taylor said. "Once the grapes are harvested, there's no active growth that you see until the spring. We water them one more time so that they're happy, but we rely on spring and winter rains to keep them growing. They'll grow up to six inches a day in the spring and summer. That's when they require the water."

Timing is critical since the new buds for next year's crop need the winter and spring rains to thrive.

"Without as much water as we'd normally have, the number of buds will be smaller than it potentially would be," Mirassou said. "Ultimately, that means less fruit. We might see yields being significantly smaller next year."

The vintners also agreed that the recent Napa earthquake should not affect supply and demand, since so few wineries lost any substantial amounts of wine.

"The valley's gone through earthquakes, and it's weathered droughts before, but the wine industry tends to come through stronger," Kinney said. "We haven't had the persistent fog that Napa has had this year. Our growing season has been absolutely stunning and spectacular."