Too Bitter? The Surprising Science of Adding Salt to Your Coffee

Even if we're die-hard coffee lovers, sometimes our coffee's bitterness leaves an unpleasant aftertaste. So, how do we overcome this problem when getting a fresh cup isn't an option?

An intriguing scientific study sheds light on the issue and offers an unexpected solution: adding a teaspoon of salt to your coffee cup.

Now, hold on a second. Salt can serve us in many ways, but in coffee of all things? You might be surprised to learn that in certain cultures, the use of salt is actually linked to coffee. Salt not only reduces the bitterness of coffee but also enhances its desired flavor.

In cultures around the world, adding salt to coffee has been a longstanding practice. For example, in Turkey, it's customary for the bride-to-be to prepare coffee with salt for her future husband and his family as an unofficial pre-wedding ritual. Similarly, "sea salt coffee", which features salted milk foam atop an iced Americano, is a popular drink in Taiwan.

In Northern Scandinavia, users have been adding salt to brewed coffee for decades. Finally, water with a high salt content is often used to make coffee in coastal regions of Europe.

So, why do people choose to do this?

In an interview, Sarah Marquardt, head of flavors at the 'Center of Excellence for Coffee,' a leading public science, technology, and innovation center, stated, "Adding salt to coffee reduces bitterness without using other additives that might distort the coffee's taste itself."

"Salt naturally brings out the sweetness in coffee and maintains its aroma and flavor. For those sensitive to bitterness, I definitely recommend adding a teaspoon of salt to their coffee."

And she’s not alone.

In 2009, food science expert Alton Brown suggested adding salt to coffee during an episode of his cooking show Good Eats. He said that for every cup of water and two teaspoons of ground coffee, half a teaspoon of salt should be added to neutralize the bitterness of the coffee. "Not only does salt cut the bitterness, but it also smooths out the stale taste of water stored in tanks. Research has demonstrated that salt is actually better at neutralizing bitterness than sugar," he explained.

Although Brown wasn't the first to introduce salt to coffee, he brought widespread attention to the technique, and today many people recognize this trick as the 'Alton Brown trick.'

The Science Behind Salt and Bitterness Reduction

Our taste buds enable us to recognize sweet, sour, salty, and bitter flavors, but our biological reactions to bitterness are different from other tastes. When we consume something bitter, calcium ions are sent to our brains. While salt can enhance both sweet and sour flavors, it tends to decrease our perception of bitterness.

"Bitter flavors activate our bitter taste receptors, signaling to our brain that we have tasted something bitter," says Sarah. "Salt, specifically sodium ions, activate salt receptors in our palate. Sodium ions bind to salt receptors on the tongue and inhibit our perception of bitterness to balance out the flavors."

"When both bitter and salt receptors are activated simultaneously, it can lead to the suppression of the bitter taste and enhance other flavor senses, like sweetness. This means that when salt is added, the sweetness in coffee is naturally elevated," she concludes.