How Are Cotton Candy Grapes Made? Pollen, Then a Test Tube

Cotton Candy grapes taste so much like the fairground sweet that plenty of people assume a lab put the flavor there. In a 2015 trade-magazine article, John Clark recalled a waitress in Aptos, California, who raved about a table grape she had eaten earlier that day. “She suspected it was some sort of GMO, but she liked it anyway,” he wrote.

Grapery, the California grower that began selling the grapes in 2011, has heard stranger theories. “We get people asking if we inject cotton candy flavor into every berry, or if we spread cotton candy over the soil and the roots pick it up,” Jim Beagle, then its chief executive, told CBS News in 2016.

Clark had reason to know better. The grape’s mother came out of the University of Arkansas fruit breeding program, where he worked from 1980 until 2023.

How are cotton candy grapes made?

Cotton Candy grapes are made by ordinary cross-breeding. In May 2003, breeder David Cain’s team hand-pollinated a University of Arkansas grape hybrid with Princess, a green seedless grape. The seeds would have aborted, so the embryos were rescued in lab culture, and one seedling was chosen in July 2005. No flavor is added, and no genes were inserted.

The record is the variety’s plant patent, US PP23,399, granted on February 19, 2013, to International Fruit Genetics, the Bakersfield company Cain helped start in 2001. It names the variety IFG Seven, sold under the trademark Cotton Candy.

The mother came from Arkansas, the father from the USDA

The Arkansas program dates to 1964, when James Moore returned to Arkansas from a USDA breeding job in Maryland, and its grape work aimed at seedless varieties for an Eastern U.S. table grape industry. Cain visited in 2001, and a 2002 agreement let IFG use Arkansas selections in crosses “with pure V. vinifera parents,” the European species behind almost all of America’s table grapes.

The patent names the parents. One is A2674, “an unnamed interspecific Vitis selection received under contract from the University of Arkansas,” meaning a numbered seedling bred from more than one grape species. Press accounts called it a Concord, and NPR reported that Cain could not say which “Concord-like grape” he used “because it’s a trade secret.”

The other is Princess, a green seedless table grape that “was developed by the USDA,” the Los Angeles Times reported. According to the patent, the new vine most closely resembles Princess, its pollen parent, but has “a very strong aromatic flavor that the Princess variety lacks.”

Seedless grapes abort their seeds, so the embryos were rescued

The cross produced what the patent calls “abortive seed traces,” seeds of the kind that start to form and then stop. Grapes such as Thompson Seedless end up seedless the same way. “Fertilization occurs, and embryos may develop, but their development is often stopped, and normal seeds cannot form,” a 2023 paper in Plants explains.

The workaround, called embryo rescue, takes out the ovules or young embryos while they are still alive and grows them in artificial media, “without the abortion caused by a natural process,” in the paper’s words. Before it, “Seedless cultivars can be used only as male parents,” researchers at a USDA fruit research station in Fresno, California, wrote in the journal Vitis in 1983, reporting seedlings raised from the “normally abortive ovules” of seedless grapes.

Those authors judged it “reasonable to assume that embryos of seedless grapes are genetically sound,” and put the abortion down to “a physiological imbalance in the parental tissues.” The 2023 paper cites their work as the first report of grapevines raised this way. Its first author was D.W. Cain, and the Los Angeles Times reported that David Cain started out in the 1970s as a USDA grape researcher in Fresno.

For the Cotton Candy cross, the seed traces were embryo cultured, the patent records, and the plant went into the field in April 2004. Cain’s team grows such embryos “in individual test tubes in the lab,” NPR reported in 2013, adding that Cain had made around 100,000 such plants before finding the cotton candy flavor. The winner was “selected as a single plant in July 2005.”

The GMO and injection rumors, checked against the record

Grapery’s FAQ page answers the GMO question with “No.” It also says “We didn’t add any cotton candy flavor” and “there are no additives or infusions in any of our grapes,” the grower’s answer to the injected berries and the sugared soil.

The FDA calls GMO the common term for foods created through genetic engineering, which copies a gene from one organism and inserts it into the DNA of another. Grape crossing moves pollen instead, brushing it “onto the female clusters of the target plant,” as the Los Angeles Times put it.

Embryo culture copies and inserts no genes either. The FDA counts cross-breeding among the “traditional modification methods” people have used “for thousands of years.” The MD-2 pineapple came out of the same kind of breeding, a cross of two earlier hybrids at the Pineapple Research Institute of Hawaii. Japanese Black cattle, the breed behind most Wagyu, also came out of crossing, of native cattle with European breeds in the early 1900s.

High sugar, low acid and a candy-scented compound

Most commercial grapes are vinifera, with a neutral flavor of sugar and acid and “no strong aromatic component,” the patent explains, so breeders have used native American species to “incorporate aromatic flavors into the vinifera species.” It describes IFG Seven’s flavor as “Similar to Toffee or Cotton Candy having a hint of Vitis riparia flavor.” Vitis riparia is the riverbank grape in the USDA PLANTS database, a wild vine that grows from central and eastern Canada south to Texas.

“Cain and I were very impressed with this selection soon after it was found, but wondered if it had too much flavor compared to the neutral-flavored grapes most Americans were accustomed to,” Clark wrote.

On vines grown near Delano, California, in 2010, the patent records about 19.2 Brix, a measure of sugar, and a sugar-to-acid ratio of about 68.6. Beagle told CBS the grapes run about 20 percent natural sugars, against around 17 percent for most table grapes.

The aroma was measured in a 2024 study led by Federica Bonello, which analyzed five table grape varieties grown in Italy and harvested in 2022.

Cotton Candy held an estimated 461 micrograms of furaneol per kilogram, more than four times the next-highest variety, at about 106. Flavor references describe furaneol’s smell as “Candy, sweet, candyfloss, caramellic,” and the authors wrote that the grape’s candyfloss odors were confirmed “through the high level of compounds like furaneol.”

Overall, though, the authors rated the grape “neutral in its aroma,” with “a notably low content of monoterpenes,” the compounds that mark Muscat-type grapes. Like the aldehydes behind cilantro’s soapy note, one compound may carry the flavor people remember, and in this otherwise plain grape the study points to furaneol.

Eight years from hand cross to store shelf

Cuttings were first taken near Delano, California, in December 2005, six years before the first sales in 2011. The patent also corrects the Los Angeles Times, which wrote in 2013 that the grape “was patented in 2010.” The application was filed on August 24, 2011, and granted on February 19, 2013.

The waitress in Aptos guessed GMO, and the grape did pass through a lab, as an embryo in a test tube during its first year. The flavor took far longer. Clark puts the whole effort at about 50 years, about 35 of them in Arkansas and about 15 in California. Strictly FYI.