Adding a small pinch of salt instead of a spoonful of sugar to your coffee is becoming increasingly popular on social media. This trick seems to remove some bitterness and bring out other flavors that may be lost otherwise.
If the idea seems strange to you, rest assured it is not as unusual as you may think. There is even a scientific basis for this type of coffee, which has been known for decades. Sodium chloride (table salt) is highly effective in suppressing bitterness in coffee and all types of food. Scientists have attributed the ability of salt to suppress bitterness to its popularity as a cooking ingredient all over the world throughout human history. By suppressing bitterness, salt allows other flavors such as sweetness to truly shine. The tongue map theory of human taste has been debunked long ago. However, there are different receptors that are sensitive to certain types of flavors, where the salt receptor belongs to the ENaC channel. Bitter taste receptors belong to a family known as TAS2Rs.
Research published in 1995 showed that salt is effective in masking bitterness. When scientists mixed sweet and bitter compounds, adding salt made the mixture sweeter and less bitter. However, suppression did not work in both directions because bitter compounds did not suppress the taste of salt. But it is still not entirely clear how the inhibition works. Nevertheless, research on mice conducted in 2013 found that while the ENaC taste is characterized by low levels of sodium chloride at high concentrations, salt also stimulates sour and bitter receptors. This is because this mixture is thought to form an unpleasant taste. Consuming too much salt at once is extremely dangerous. But a little salt can go a long way. For example, it was common to use salt on eggplant to reduce its extreme bitterness, a practice that is no longer necessary since we have suppressed bitterness. Salting is also a common way to reduce the bitterness of Brussels sprouts. This is according to a report published on "Science Alert" website