Honey Crisp apples ripen in the morning sun at Boothby's Orchard and Farm in Livermore, Maine, Sunday Sept. 9, 2018. Credit: Russ Dillingham | AP

What sets apart the flavor of one apple from another? It comes down to the cellular level, experts say.

“The flavor of fruits is largely from sugars and acids,” said Renae Moran, associate professor of pomology at the University of Maine. “The relative amount of sugars and fruity acids is perceived as sweetness, tartness or both.”

A McIntosh has a tart crispness, while Honeycrisp is sweet and juicy. Other apples, such as the Red Delicious apple, which is relatively low in sugars and acids, have a flavor that is considered somewhat bland, Moran said. A Northern Spy apple, on the other hand, has a high acid level that gives it a tart flavor, and the Crimson Crisp has high contents of both sugars and acids, making it intensely flavored.

There are hundreds of cultivated varieties of apples — all members of the Rosaceae family, and each having its own, unique color, texture and flavor characteristics.

“Some are highly aromatic, such as McIntosh and their flavor also comes from their aroma,” she said. “As we bite into them certain compounds are released from the flesh and become gaseous, thus making it easy to smell them [and] adding to the over all taste experience.”

Differences are also due to individual varieties, many of which are the result of decades of cross-breeding and cultivation by apple growers, Moran said. They also react differently to different environmental conditions.

“Each variety has its own characteristic sugars and acids,” she said. “They each react differently to environmental conditions.”

Those reactions are what helps make Maine a great spot for the cold-weather apples, according to Moran.

“Colder regions grow sweeter apples,” said Matt Tellerin, owner of Treworgy Orchards in Levant. “We are on the northern border of the point where it gets too cold to grow apples, and that is why we can grow apples in Maine they can’t grow in places like Pennsylvania or New York.”

At his orchard, Tellerin said he grows primarily McIntosh apples, what he calls the “king of Maine apples” due to their popularity.

“Maine is really known for its macs,” he said. “That’s our heritage apple.”

Tellerin said the McIntosh’s sweet and tangy flavor is best experienced right off the tree, as it does not have a long shelf life once picked.

Once picked — or if left on the tree too long — the McIntosh produces larger amounts of the ripening hormone ethylene which causes the fruit to soften by breaking down the cell walls and the complex sugars in the apple’s flesh.

The result, according to Moran, is a “smooshy” apple.

That is something no one wants, said Brent Mullis of Mullis Orchards in Corinna.

“Certain varieties break down faster than others and can be damaged more easily because they get smooshy after being picked no matter how you store them,” Mullis said. “Apples like the Honeycrisp don’t do that if you put them in cool storage, they can stay as crunchy as when you picked them for days.”

Follow the Bangor Daily News on Facebook for the latest Maine news.

Julia Bayly

Julia Bayly

Julia Bayly is a reporter at the Bangor Daily News with a regular bi-weekly column. Julia has been a freelance travel writer/photographer since 2000.