If the color of the cup is different, the bitter taste of coffee is also different.

The world drinks more than 2.25 billion cups of coffee every day, and most of the coffee seems to taste bitter.

Recently, a study shows that coffee lovers can make their coffee taste sweeter by changing their coffee cups in different colors. Scientists say blue or transparent coffee cups, which are popular in some coffee shops, can reduce the bitterness of coffee without adding sugar.

The researchers, from the Commonwealth University of Australia and the University of Oxford in the UK, began to prove the truth after a barista said that a white cup would make the coffee taste more bitter.

They found 36 volunteers to take part in the experiment.

Then test the claim with coffee cups in blue, white and transparent. In one of the experiments, volunteers thought white coffee cups "enhanced" the taste of coffee more than transparent coffee cups, according to an academic report published in the journal Flavour.

In the second experiment, the volunteers thought the coffee in the blue and transparent coffee cups tasted sweeter than the white coffee cups, and of the two coffee cups, the volunteers thought the coffee in the blue coffee cups was the sweetest.

Scientists believe that people may associate brown with bitterness, and because the coffee in a white coffee cup looks closest to brown, people will also think it tastes the bitterest.

The lead author of the report, Dr George Doorn from the Commonwealth University of Australia, wrote in an article at the request of The Conversation: "our research clearly shows that the color of coffee cups does have an effect on people's sense of taste and smell when drinking coffee. Our academic report on the impact of coffee cup color on coffee taste suggests that coffee shop owners, baristas and porcelain manufacturers should all seriously consider the color of their coffee cups, because this potential effect can affect the number of repeat customers in their business. "

The fact that color can change the taste of food is actually old news. A study published last year showed that if you put the same red strawberry mousse on two different plates in black and white, people would think that the mousse on the white plate was 10% sweeter than the one on the black plate, and the taste was 15% better.