Want A Sweeter Cup of Coffee? The Eyes Have It

We already know that coffee teases and tantalizes the taste buds and tickles the nose. But if you want a less bitter cup of coffee, it turns out the eyes have it.

A study conducted by George H Van Doorn, Dianne Wuillemin and Charles Spence in the online journal Flavour (abstract and full article) suggests that the taste of your cup o' joe can be influenced not just by the things you'd expect, like the grind, process, and brew time used, but also by the color of the cup your coffee's served in.

Two versions of the experiment were conducted. In the first, a café latte was served in three different mugs (transparent, white and blue), and participants were asked to rate the taste of each. The respondents rated the coffee in the white mug as significantly more bitter than the coffee in the transparent or blue mugs.

To eliminate the possibility that there was something in the makeup of the mugs used that was influencing the taste of the coffee, the experiment was repeated a second time. This time, clear glass mugs were used exclusively, with the addition of white and blue sleeves. The results were consistent -- again, the coffee in the white mug was rated as more bitter. In both experiments, the clear and blue mugs tasted sweeter to the participants, suggesting that it's the color contrast between the coffee and its container that influences how the taster perceives the coffee.

There's no magic or sorcery here. There's no special property of a white mug versus a clear glass coffee cup or your favorite blue travel mug that's changing the taste of your coffee. What there is, instead, is a bit of subtle trickery. As with anything else involving your five senses, it's all a matter of perception. In other words, what Van Doorn et al. have stumbled upon amounts to a placebo effect; there's no actual change to the contents of your cup, all else being equal.

However, what the research suggests is that whether you're serving coffee at home or in your own cafe or restaurant, it would probably be wise to pay attention to the interplay of color and coffee. Higher contrast (as would be found in a white, off-white, or light yellow cup) leads to the perception of a more bitter taste, while the use of clear glass, blues, blacks, and dark browns eliminate the color contrast and make the coffee seem sweeter. If you prefer your coffee to fit a certain flavor profile, now you know how to finesse your mind (and your tastebuds) into thinking your latte tastes a certain way.

Photo credit: © Karlien Du plessis | Dreamstime Stock Photos