The short answer

Salt makes food taste better because it enhances sweetness by reducing bitterness, concentrates flavor compounds by decreasing unbound water, improves the smell and texture of food, and makes food taste saltier.

The long answer

Legendary American chef James Beard once asked, "Where would we be without salt?"

I'll answer that: Dead. We'd be dead without salt.

Salt, or sodium chloride, is an essential micronutrient to keep our body humming along. It's used for neuron-to-neuron communicating, contracting and relaxing muscles (which ​prevents muscle cramps​), and maintaining the proper balance of water and minerals.

However, our bodies can't store salt well, which is why we have to keep eating it. Fortunately this is not a burden because salt makes food taste better.

A quick refresher on how taste works: Our tongues have taste buds which contain multiple types of specialized taste receptor cells.

Humans can detect five basic tastes: sweet, sour, bitter, umami, and, or course, salty. As we eat, food molecules dissolve in saliva and stimulate different taste receptor cells, which send signals to your brain about what you're tasting.

Before I get tongue-tied talking about tongues, let's get into five reasons why salt makes food taste better.

Reason #1: Salt reduces bitterness, which makes other flavors more pronounced.

There's a reason why your recipes containing bitter foods, like kale, radicchio, or grapefruit, call for salt. Sodium seems to interfere with the binding of bitter flavor compounds and bitter taste cell receptors. This means when you add salt to food, it blocks the taste of bitter.

However, our sense of taste is not one-dimensional. When you reduce the amount of bitterness in food, it causes our perception of sweetness to become more pronounced. ​One study​ ran a scientific taste test to determine how adding sodium compounds affected the perception of taste. They compared the bitter and sweet tastes of:

• Sugar alone

• Urea (a bitter compound) alone

• Sugar + urea

• Sugar + urea + sodium acetate (a mildly salty compound)

When sugar and urea were combined, the perceived taste of both sweetness and bitterness were reduced. But when the sodium acetate was added, the sweetness increased and the bitterness decreased. This study provided real data to show that adding sodium reduces bitterness, thereby enhancing sweetness.

Scientists aren't exactly sure why salt seems to increase the perception of sweetness. But, at least in mice, a protein responsible for pulling sugar into the sweet taste receptor cells can't function without sodium.

Reason #2: Salt reduces unbound water in food, making flavors more concentrated.

Your food contains two types of water: ​bound and unbound water​. Unbound water is what you can remove by squeezing, cutting, or pressing (e.g. juice from an orange). Bound water is so tightly bound with other food molecules it doesn't behave like normal liquid water. Okay, water this, water that – what does this have to do with salt?

Salt has kind of a superpower when it comes to water. When salt is added to food, it dissolves into its ionic components, Na+ (sodium) and Cl- (chloride). These ions attract water compounds and bind themselves to water. What was once unbound water is now bound water.

With less unbound water, the concentration of flavors becomes increased, like how adding only a small amount of water to instant coffee creates a stronger cup of coffee.

Reason #3: Salt makes food smell better.

Salt's ability to reduce unbound water doesn't just make food taste better, it makes food smell better.

Known as volatile compounds, these molecules easily evaporate into the air, creating food's aroma. With less unbound water to hold onto them, these smelly molecules are more likely to escape from the food into the air.

Our sense of smell is responsible for about 80% of what we perceive as flavor, so salt's ability to increase food's aroma is a core reason why it helps food taste better.

Reason #4: Salt improves the "mouthfeel" of food.

Salt also seems to improve the physical texture of food, also known as its "mouthfeel." In a 1985 study, volunteers compared unsalted and salted pea soup. The salted pea soup was reported to score higher on thickness and fullness when compared to the unsalted soup, leading to a better "mouthfeel."

It's not fully understood why salt affects the physical texture of food, but personally I'd presume it has to do with the reduction of unbound water in the food.

Reason #5: Salt makes food saltier.

Okay this last one's obvious, but salt tastes salty, and we are hardwired to crave salt! You shouldn't overdo it – too much salt in your diet can lead to maladies like high blood pressure – but we need salt, so it's natural that we enjoy the taste of it.

Check out some other curious questions:

Sources

Bartoshuk, L. M., McBurney, D. H., & Pfaffmann, C. (1964). Taste of sodium chloride solutions after adaptation to sodium chloride: Implications for the “Water Taste.” Science, 143(3609), 967–968. https://doi.org/10.1126/science.143.3609.967

Breslin, P. A., & Beauchamp, G. K. (1997). Salt enhances flavour by suppressing bitterness. Nature, 387(6633), 563–563. https://doi.org/10.1038/42388

Green, H. (2018, February 17). Why Does Salt Make Food Taste Better?. YouTube. https://www.youtube.com/watch?v=ATrSoMlx5PE&ab_channel=SciShow

Gritzer, D. (2023, February 27). Flavor Science: How We Taste Sweet, Sour, Salty, and More. Serious Eats. https://www.seriouseats.com/how-do-we-taste-salt-sour-acid-sweet-bitter-flavor

Harvard T.H. Chan School of Public Health. (2024a, May 9). Salt and sodium. The Nutrition Source. https://nutritionsource.hsph.harvard.edu/salt-and-sodium/

Henney, J., Taylor, C., & Boon, C. (n.d.). Taste and Flavor Roles of Sodium in Foods: A Unique Challenge to Reducing Sodium Intake. In Strategies to Reduce Sodium Intake in the United States. essay, Institute of Medicine (US) Committee on Strategies to Reduce Sodium Intake; National Academies Press. https://www.ncbi.nlm.nih.gov/books/NBK50958/

Hiskey, D. (2012, November 28). Why Salt Enhances Flavor. Today I Found Out. https://www.todayifoundout.com/index.php/2011/09/why-salt-enhances-flavor/