A Complex Cup of Joe

August, 25 2016

There is a popular beverage that sometimes tastes like blueberries, butter, clove, grapefruit, tomato, lychee, apples, or chocolate. No, I’m not describing a flavor-morphing concoction like Willy Wonka’s three-course-meal gum. Coffee displays an incredible range of flavors and smells, but it takes a fine-tuned palate to detect them.

Coffee’s complex chemistry varies by geographical region. Everything from soil composition, climate, processing techniques, coffee plant species and cultivar, elevation, brewing temperature and roasting temperature can influence the subtle notes in your cup of joe. Even a single bag of coffee, grown in the same country and region, has the potential to taste many different ways.

“Guatemalan coffee does not taste one way,” said Adam Lau, education and wholesale manager at Ipsento Coffee in Chicago.  “There are five different regions in Guatemala. We discovcoffee handsered that a coffee from one region is actually more chocolatey, nuttier and more approachable. Whereas, there’s one from another region that tastes like pineapples and coconuts,” he said.

Most of the coffee consumed around the world—about 70 percent—is a variation of Arabica species, according to the Specialty Coffee Association of America. Within the Arabica species, there are many variations, or cultivars. Some emerged through random genetic mutations in the original species, but most cultivars were created by people who selected for certain traits or flavors that they hoped to amplify in the new variety.

The Specialty Coffee Association of America collaborated with the World Coffee Research organization to create the “Coffee Taster’s Flavor Wheel.” It’s similar to the color wheel hung on the wall in grade school art classes, but each color represents a different flavor or smell in nine general categories.

A coffee that seems sour or fermented, according to the flavor wheel, can be further categorized as butyric acid, winey, or whiskey. Similarly, a coffee that reminded someone of spices, can be described as pepper, clove or anise.

coffee wheel
“Coffee Taster’s Flavor Wheel” made by the Specialty Coffee Association of America

The flavor wheel is a resource for farmers, coffee producers, or coffee shop owners who need the vocabulary to describe what property they are detecting in a cup of coffee. This scientific process occurs at cupping events, where coffee is measured out in precise amounts and analyzed in the dry, and wet stages.

Though researchers have uncovered the entire chemical composition of a coffee bean, we still do not have a solid understanding of which chemicals correlate to which flavors and or smells. The few that are known only convey general characteristics of a cup of coffee.

For example, citric acid constitutes a large portion coffee’s total acid content, and contributes to the overall perception of acidity in the finished product. Other acids include quinic acid, chlorogenic acid, phosphoric acid, and acetic acid, which accumulates during the fermentation process after the coffee cherries are harvested.  2-Furfurylthiol is responsible for roasted flavor, while acetylmethylcarbinol gives some coffee a buttery taste.

A defective coffee often tastes “aged, green, parchment-y,” or “paper-y” and “doesn’t have any complex flavor notes,” said Intelligentsia employee Rebecca Montalvo. Good coffee will usually have a perfect balance of fruity notes and body, she said. Body is described as the heaviness in a coffee sensed at the back of the palate, according to Sweet Maria’s Flavor and Roasting Terms guideline.

coffee cupping
The evaluation second stage in a coffee cupping is breaking the crust to assess the wet aromas of the coffee

“So after every stage of examining the coffee, testing their characteristics, we’ll come together and discuss what we’re smelling. Then we’ll grade it at the end,” said Lau. He said that during coffee cuppings, someone might dislike the taste of a specific coffee while it’s hot, but then love it as it begins to cool because the flavors become more pronounced in the brew.

The time the coffee cherry was picked from the plant also affects the flavor of the resulting coffee bean. “If you pick it too soon, you’re not going to let those sugars develop, and you’re going to get an underdeveloped cup of coffee,” said Montalvo. “You’re not going to taste those brighter fruit notes,” she said.

If the cherry was left to develop on the tree for too long, said Montalvo, the opposite effect may occur. “It could be way too tart. Almost sour notes in it,” she said. Neither extreme is favorable to a farmer or coffee producer, as balance is ultimately the goal in a quality cup of coffee.

“You want to find something that lands right in the middle,” she said.https://youtu.be/XGJ4s_1O6UY


Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s