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Wine and Chocolate, with Tannins as Cupid

Tannins, naturally occurring compounds that are often bitter or astringent, heavily influence both wine and chocolate flavors

by Scott Weybright-Washington State University News Office
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red winePhoto credit: Mick Stephenson, Wikimedia CommonsPROSSER, Wash. – Wine and chocolate go together at Valentine’s Day like hearts and arrows. And it turns out the two icons of romance share some scientific similarities.

Tannins, naturally occurring compounds that are often bitter or astringent, heavily influence both wine and chocolate flavors, according to Washington State University enology professor James Harbertson.

He and his team have begun preliminary research to study tannins in partnership with a premium chocolate company headquartered in Quito, Ecuador, called To’ak Chocolate.

Both mellow with age

The enologist and the chocolatier share a curiosity about what tannins do as they age.

“Wine becomes more mellow, less astringent as it ages and we want to find out what changes occur in the tannins,” Harbertson said. “To’ak has the same question about chocolate. Their older bars are less bitter and they want to know why.”

Based on some of his earlier research, Harbertson is hopeful that the match will be mutually beneficial.

“A few years ago, I actually used chocolate as a model for how tannins change,” he said. “Tannins in chocolate are much more predictable and uniformly sized. Wine tannins are more difficult to work with, so I started with chocolate. Coming back to chocolate is a lot of fun.”

Chocolate aged in cognac barrels

To’ak ChocolateTo’ak ChocolatePhoto courtesy of Washington State UniversityJerry Toth, co-founder and CEO of To’ak said researching the properties of chocolate is important to his business.

“Our plan is to continue studying the effect of aging on tannins over a 20-year period … or as long as we continue to see changes over time,” he said.

Harbertson said the chocolate from To’ak is different from any chocolate he’s ever seen.

“It’s incredibly astringent and smells amazing,” he said.

To’ak is known for aging their chocolate in different vessels, including old cognac barrels. They have a vintage chocolate bar priced at $345.

Sharing the love

Harbertson said unexpected connections like this research with To’ak are one of his favorite things about being a scientist.

“I got a call out of the blue from someone at To’ak because they read an article I wrote about tannins,” he said. “I don’t often look outside wine, but if I don’t broaden my viewpoint, I may miss a connection like this.

“It’s great that we can both learn something about a topic we both love,” he said.

It’s a match made for Valentine’s Day.

More info on the WSU viticulture and enology program can be found at