How coffee increases the perception of sweet tastes


New research from a pair of Danish scientists at Aarhus University has found that the bitter characteristic of coffee may cause a person to be more sensitive to sweetness. The study found that this effect is independent of caffeine and helps explain why many people enjoy the dark chocolate experience with coffee.

The researchers recruited 156 participants to test the effect of coffee on the sensation of taste and smell. After conducting baseline tests to determine initial taste and aroma levels, participants consumed lukewarm espresso. Soon after, all participants were asked to drink a small cup of tap water to clear their palates. They then underwent the same tests a second time. No changes in the sense of smell were observed in the study, but research showed that thesweet taste was enhanced after consuming coffee.

After drinking coffee, a person becomes more sensitive to sweet and conversely less sensitive to bitter.

This result was unexpected because previous studies have suggested that exposure to bitter tastes generally inhibits the perception of sweet tastes. For example, caffeine and quinine, two compounds found in coffee, were previously found to directly inhibit (slow down) the activity of certain sweet taste receptors.

Theeffect of coffee on taste sensations was short-lived in all volunteers and was only noticed when they drank this hot beverage.


The researchers conducted the experiment a second time with decaffeinated coffee and saw the same results. This suggests that caffeine does not play any particular role in changing the taste when drinking coffee.

"We already know that our senses influence each other, but it is a surprise that sweetness and bitterness are so easily influenced," says Alexander Wieck Fjældstad.

The researchers noticed a discrepancy in the results between the first and second research. The way in which specific bitter compounds suppress the perception of sweet taste suggests that there is an unknown combination of compounds in coffee that leads to this dynamic change to a bitter-sweet taste.

The research explains why people like coffee and dark chocolate together. This is because the taste of chocolate is not as bitter because they have a subdued bitterness after drinking coffee, which increases the perception of the sweet taste.

In addition to explaining why the classic combination of dark chocolate and coffee is so desirable and popular, the research offers new insights into how dynamic our perception of taste is. The study highlights new kinds of research on food additives that can amplify the perception of sweet taste without increasing the sugar content of foods.

"Further research in this area could have implications for how we use sugar and sweeteners as food additives," Wieck Fjældstad adds. This research could be beneficial for a number of groups, including those who are overweight and diabetic. "

Source: the study was published in the journal Foods.