Does it improve the coffee if you add salt?

This news almost made us sick: a study claims that adding salt to coffee improves its taste. What seems contradictory and even inadvisable (who has not heard that coffee with a good handful of salt causes vomiting) has a scientific basis, but we advance it to you, before you get like Salt Bae on your El Jardin filter: do not add salt to the coffees of NOMAD, because this salt trick only works with poor quality coffees.

It is true that in some cultures it is customary to drink coffee with some salt. As Mark Kurlansky explains in Salt. A World History (Walker, 2002), "the Swedes picked up the Laplander people's habit of drinking coffee with salt". Also, as explained by UNESCO, which added Turkish culture and tradition around coffee to the Intangible Cultural Heritage list in 2013, "many brides prepare coffee with salt for their future husbands to measure how much they love them." This courtship ritual has evolved: when the groom's family visits the bride's family before the wedding, the bride must prepare a perfect Turkish coffee. It is said that in the past, if the bride liked her suitor, she would add sugar to the coffee, and if not, salt. Now, things have changed, and brides subject their future husbands to this little test.

Salty vs. bitter

The explanation has to do with bitterness. In those coffees where the bean is of poor quality and the roasting has not respected its flavor profile and has been prolonged too much until very dark roasting, a very powerful bitterness predominates in each sip due to the appearance of two compounds: chlorogenic acids and phenylindanes. And it can also appear due to over-extraction. It is this taste that is generally associated with coffee (although it has nothing to do with good coffee) and that makes many people not dare to drink it without a sweetener or without milk. But a good coffee is not like that: whoever has tasted it, knows it, as the poet Lope de Vega used to say.

However, the salt trick can work if you're unlucky enough to find yourself without a good specialty coffee nearby. You know: meals at friends' and family's homes that still don't have a good coffee subscription or trips where you haven't been able to take a good instant specialty coffee with you and you are condemned to drink that hotel coffee that, sadly, leaves a lot to be desired.

Thus, salt would help to improve a coffee more bitter than Fernet in the following way: while bitterness activates the bitterness receptors on our tongue, the salt (actually, the sodium ions) that we add to that terrible coffee would make the salt receptors also activate and enter into competition to transmit the information to our brain.

At the same time, salt is a sweet flavor enhancer (that is why all pastry doughs, such as croissants and cookies, have a small percentage of salt), and would make the tiny sweetness of that bitter coffee stand out more instead of going unnoticed by the unpleasant bitterness of a poor quality coffee.

This phenomenon is called 'cross-perception': the salt and bitterness receptors are activated at the same time and the salt wins, deactivating to some extent the sensation of bitterness, while at the same time enhancing the sensation of sweetness.

Coffee with salt recipes

In case you would like to try adding salt to coffee, there are several formulas to do so. According to food science expert Alton Brown, just add half a teaspoon of salt to each cup of coffee containing two teaspoons of coffee to counteract that infernal bitterness.

On the other hand, James Hoffman, coffee consultant and World Barista Champion recommends creating a solution of water with salt at 20% concentration, and adding 0.3 g of this to the coffee. More simply, Sara Marquart, from The Coffee Excellence Center proposes 0.5 g of salt per 1 l of coffee already prepared, and the expert Scott Rao suggests 0.15 g of salt per 100 g of filter or espresso coffee.