Brad Goering is a fourth-generation wine grower in Clements.

He has had to deal with August heat every year on his 500-acre vineyard.

But he has never had to deal with persistent extreme heat this time of year during harvest season.

"Due to the duration of the heatwave that's expected, and the high temperatures associated with that, we've had to put on a lot more extra water, which is the biggest thing that could affect the crop," Goering said.

He grows eight varieties of wine grapes for dozens of wineries throughout California, and he says the key is to keep the grapes hydrated, before and after the heat arrives.

Otherwise, the grapes become dehydrated.

The heat can force the crop to shut down and go into "survival mode," Goering said.

He is also leaving extra foliage around the fruit instead of trimming it now, to shade it from the sun until the grapes are ready to be harvested.

Another problem growers face because of the exceptional heat is seeing white and some red varieties of grapes mature all at once.

"We're a little nervous that we are seeing things all come together and ripen at the same time which could create some logistic issues between covering ground harvesting and tank capacity at the wineries being able to receive the fruit,” Goering said.

Still, Goering says he expects a "very good" harvest despite the extreme heat.

The wine grape is San Joaquin County's number one cash crop worth $600 million last year.

Wine grape value also increased $70 million over the previous year in the county.