Coffee tasting: the lesser-known factors that influence the sensorial experience

In the world of high-quality coffee, every detail matters in delivering a superior sensory experience. When considering factors that can influence the perception of coffee's flavor and aroma, traditional aspects like roasting and extraction usually come to mind. But the material, shape, and color of the vessel in which coffee is tasted can also play a fundamental role.
In this article, we will discuss how choosing the right vessel, along with the effect of color, can enhance and elevate the perception of coffee flavor, opening new horizons of sensory experience.

Before we begin: defining taste, aroma, and flavor

Before delving into details, it's crucial to understand the key terms:

•     Taste (or gustation): represents the perception of fundamental tastes, such as salty, bitter, sweet, sour, and umami, on the taste buds when we eat or drink.
•     Aroma: is the distinctive smell caused by a complex mixture of volatile compounds.
•     Flavor: is the combination of taste and aroma perceptions.

The role of visual perception 

Flavor perception isn't just about the palate; it also involves the eyes (How bitter is coffee? - Rai News). The sight of the vessel's contents can influence the psychological perception of flavor even before tasting the coffee. When we see an espresso in a glass, we are predisposed to expect a drink that recalls sensory experiences we've had with similar liquids. This is what psychologists call emotional conditioning.

You can experience this effect with a simple experiment. Place two glasses in front of a friend:

• a glass containing an espresso where you've dissolved 3 teaspoons of sugar.
• another glass containing the same espresso, but with added white milk.

Then ask your friend which of the two glasses contains the sweeter drink. Most likely, they will answer that the glass with added milk is sweeter. This demonstrates how much visual perception can influence flavor perception.

George Van Doorn, a researcher at the School of Health Sciences and Psychology at Federation University Australia, conducted a study that showed coffee served in a white cup is generally perceived as more bitter than that served "in a glass."

But the researcher went further and conducted a second experiment, using identical glass cups, but with different colored handles. This second study showed that the distinctive color of the cup handle affects the evaluation of the coffee's taste. In particular, coffee was rated as "less sweet" when served in a completely clear cup compared to cups with colored handles.

The shape and material of the cup: how does perception change?

A study conducted in 2018 showed that the shape of the vessel in which coffee is served has a significant impact on the sensory perception of coffee. This has led many coffee lovers, including baristas and participants in international competitions, to explore cups with different shapes to emphasize the sensory experience.

The choice of coffee vessel shape is not just an aesthetic matter; it directly affects the perception of taste and aroma.

Espresso in glass: what changes compared to a ceramic cup

The material of the vessel in which coffee is served can also significantly influence the perception of taste and the overall experience. A clear example is the preference for glass when drinking espresso. Glass, in fact, is a good thermal conductor, which means it cools down faster. So, an espresso served in a glass might have a slightly lower temperature, affecting the perception of its flavor.
The preference for glass when drinking espresso also has roots in history and traditions. In Rome, particularly, it's common to serve espresso in small glass cups instead of ceramic ones.
The story goes that this is due to the idea that baristas might not have thoroughly cleaned ceramic cups during peak hours. Customers, concerned about hygiene, started asking for coffee in small glass cups so they could visually check the cleanliness of the container from a distance. Whether this story is true or an urban legend remains a matter of debate, but it demonstrates how traditions and perceptions can influence consumer choices.

The ceramic cup is another common vessel for coffee tasting. Its main characteristic is its ability to conduct heat efficiently. Ceramic quickly reaches the temperature of the liquid poured into it and maintains it consistently over time. This property is particularly useful when you want to keep a beverage, such as espresso or cappuccino, at the right temperature throughout the tasting.
Porcelain can be used either at room temperature for coffees to be cooled quickly, like filter coffee, or pre-heated for beverages to be kept at a constant temperature.

Paper or Plastic Cups

In addition to glass and ceramic, other materials are used to serve coffee, often in different contexts. Paper and plastic, for example, are commonly used for takeaway cups.
Paper and plastic act as thermal insulators, meaning they retain the liquid's temperature for a longer period compared to glass. This can be an advantage if you want to consume a milk-based beverage slowly, but it can pose a risk of scalding when drinking an espresso quickly, before it loses its aromas. Furthermore, paper cups might release unpleasant paper notes, compromising the coffee tasting experience.
It is also important to note that the use and disposal of paper and plastic cups can have a significant environmental impact. Therefore, many people are looking for more ecological and sustainable alternatives. Today, there are more performing, hygienic, and ecological takeaway materials that can be preferred to reduce environmental impact.

How the color of the cup influences coffee tasting

In the world of high-quality coffee tasting, details are fundamental to offering an exceptional sensory experience. We have already discussed how the shape and material of the vessel can influence coffee perception, but there is another interesting aspect to explore: the influence of color on flavor perception.
For most people, color is associated with distinct tastes and flavors. For example, red is often associated with sweetness, yellow and green with acidity, white with saltiness, and brown and black with bitterness. These associations between color and taste are deeply rooted in our subconscious from childhood.
 
A key concept in this dynamic is "specific sensory satiety." When our senses constantly receive the same stimulus, we quickly become bored. This applies not only to flavors, but also to textures and colors. For this reason, we often see candies offered in a variety of colors: to keep us interested. Studies have shown that we tend to serve ourselves more of a food product if it has a variety of colors. This might explain why we often underestimate quantities when different colors are present.
 
The associations between color and taste are not limited to foods and beverages, but can also extend to the surrounding environment. For example, the color of tableware, walls, furniture, and lighting can influence the perception and judgment of food and drinks.
In one study, tourists were willing to pay more for a glass of wine when tasting it under blue or red light compared to green or white light.
 
In summary, color is not just an aesthetic feature, but an element that can profoundly influence our perception of taste and culinary experience. Whether it's food, coffee, or the surrounding environment, color plays a fundamental role in our sensory experience.
 
To summarize the various points discussed, visual perception conditions our emotional perception of flavor, demonstrating how susceptible the human brain is to visual conditioning. The shape and material of the vessel play an essential role in the coffee's temperature and perception, directly influencing the perception of taste and aroma. Finally, color, in addition to influencing taste perception, also impacts the chromatic choice of the surrounding environment, suggesting that color psychology can be creatively leveraged to enhance the sensory and visual experience of food and coffee.

The art of serving espresso, in short, is not just about preparation skills, but involves several factors that can transform the tasting into an engaging and memorable experience.