Larry Coia was happy with the 4,500 pounds of blaufränkisch grapes, an Austrian red, that he harvested on a recent Monday from his 15-acre vineyard in New Jersey’s Atlantic County, where he had already brought in merlot and several whites — chardonnay, albariño, and viognier.

“September has really turned things around,” Coia said while, on an unseasonably hot morning, five pickers snipped off dense bunches of dark purple grapes and let them fall into yellow trays called lugs at their feet.

It was not the best August for grapes. “It was cool, and we had those periods of rain, but in between it wasn’t terrible,” said Coia, who has been growing grapes in New Jersey since 1975.

When the blaufränkisch harvest was done, Coia didn’t load the grapes into his own crusher-destemmer. Instead, they were destined for a cross-state journey to Mount Salem Vineyards in Hunterdon County.

Why not have his own winery? “I just have no interest in selling wine,” Coia said, though if the right investor came along with skills in the marketing and selling end, he would consider it, he added.

For now, Coia, 66, who also sells to Sharrott Winery in Winslow Township, remains a coveted player in the growing New Jersey wine industry: a grape grower willing to sell fruit to winemakers who face a grape shortage.

“Even if you can find them, the quality of those grapes can be a real problem,” said Peter Leitner, who is the founder of Mount Salem and has been buying grapes from Coia since 2011. “I’ve bought grapes from other growers before and, frankly, have not had good experiences.”

New Jersey has tough growing conditions for grapes, with levels of humidity, rainfall and pests that don’t exist in prime growing regions west of the Rocky Mountains, Leitner said.

Like Leitner, Scott Donnini, an owner of Auburn Road Vineyard & Winery in Salem County, has had to cut off relationships with growers whose fruit was not good enough. The crop is hard even for farmers. Just a few weeks ago, Donnini had to negotiate a price with a farmer who was conscientious but had a bad harvest.

Under the best of circumstances, a tension exists in the relationship between a winery and a grape grower. “The grape grower wants to produce lots of fruit because he’s getting paid by the ton,” Donnini said, but the winemaker is happy with higher-quality grapes and lower volume.

Sometimes, reduced volume is not a choice. Pam Horovitz estimated that she and her husband lost 20 percent to 30 percent of their merlot grapes this year to turkeys, deer and wasps.

Dustin Tarpine, an owner of Vinetech Vineyard Management Co., said Vinetech has developed close to 20 vineyard acres a year since its founding in 2013 and manages just shy of 100 acres, mostly for owners who don’t have wineries.

“For a lot of people, it’s become a hobby project once they become successful in their own right,” Tarpine said. “I think another reason at least our clients are getting into it is because they think they might see a real estate opportunity.”

Among Vinetech’s clients is Orley Ashenfelter, who recently bought 10 acres adjacent to Coia’s. He’s a Princeton University economics professor who developed a formula for predicting the quality and prices of Bordeaux wine. On his South Jersey vineyard, Ashenfelter planted cabernet sauvignon, cabernet franc and petit verdot. He plans to sell the grapes to New Jersey wineries.

“There’s no question that people are making wines that are high quality. The bad part is that New Jersey has this horrible reputation for everything. Unless it’s pizza or Springsteen, everybody thinks it’s horrible. The reality is completely different,” said Ashenfelter, who is also president of the American Association of Wine Economists.