Scientists have identified five basic tastes: sweet, salty, sour, bitter, and umami. Umami, the fifth taste, is savory and comes from glutamates, naturally occurring in meats and some vegetables.

Fungiform papillae on the front, side and back of the tongue house taste receptors that detect flavors. Each person has a different number of papillae and receptors, which affects their ability to taste foods.

Sour

Until recently, sourness has been associated exclusively with acids that donate hydrogen ions. When an acid molecule enters the taste receptor cell it can dissociate, leaving a positive hydrogen charge and activating the taste receptor.

The taste of sourness can also be generated by adding baking soda, or sodium bicarbonate (the chemical that reacts with acids to generate the bubbly effect seen in science fair volcanoes). Early studies suggested that the relative intensity of sourness of various organic acids was related to their buffer capacity and molar concentration, but later investigations indicated that this is not the case. Instead, many other properties of the acid determinably affect its sourness.

Sweet

Although a great variety of chemical substances are known to taste sweet, elucidation of the molecular basis for sweet tasting remained elusive until recently. It has now been established that the human T1R2 and T1R3 G protein-coupled receptors dimerize to form a broadly tuned sweet taste receptor (1).

Scientists now know that sweetness is a property of specific interactions between parts of a sugar or artificial sweetener and the receptor proteins, which are like spaces in a jigsaw puzzle waiting for the right-sized, specifically shaped molecule to fit into them. One theory of this interaction is the AH-B-X theory, which proposes that sweet compounds have presumed AH (hydrophilic), B (hydrophobic), and X (London dispersion force) binding sites in the receptor proteins.

Salty

Salty, meaning containing salt or tasting like salt, is one of the five specific tastes sensed by taste receptors. It is believed to be mediated by sodium channels on the surface of taste receptor cells.

The taste of saltiness is an innate human preference that may contribute to physiological needs. It is also a major factor in the taste of food and beverages.

A person can be described as being salty when they use profanity, are sarcastic or cynical, or are using a four letter word. This slang is popular in the online gaming and social media community. It is often accompanied by the hashtag #salty.

Bitter

Bitter flavors may sound unpleasant, but studies have shown that including bitter foods in the diet can help boost a person’s synthesis of digestive enzymes. Bitter foods also increase nutrient absorption, promote hydration and support the health of the gut microbiome.

Bitter taste molecules fit their corresponding receptors on the tongue like keys into locks, sending messages to specific parts of the brain. This ability allowed our ancestors to detect and avoid toxic substances that could cause disease or even death. People with different bitter sensitivity are related to variation in the expression of a gene (PAV-TAS2R38) that encodes for one of the bitter taste receptors.

Savory

Savory, according to Merriam-Webster, is a term that captures a specific taste sensation. Foods that are savory have a flavor profile that is not sweet, but they can possess all other flavors, including salty, bitter and sour.

In culinary terms, savory is a seasoning that complements center-of-the-plate foods such as meat, soups and pate. Its distinctive piquancy is a key ingredient in the classic blend of fines herbes, and its robust flavor holds up well during long cooking processes, such as in casseroles or stews.

The herb savory (Satureja hortensis or Satureja montana), is a versatile plant that grows as an annual in the mint family. It has a peppery flavor reminiscent of thyme, although winter savory is stronger and better suited to a salt-free diet.

Umami

For years, scientists focused on salty, sour, sweet, and bitter flavors. In 1908, Japanese scientist Kikunae Ikeda defined a fifth taste that he called umami, meaning “pleasant savory taste.”

Dishes lacking in umami are one-note and bland. Umami comes from foods rich in glutamates, which includes dashi broth made with kombu seaweed and dried bonito; miso soup; shiitake mushrooms; Parmesan cheese; and long-cooked stews.

Many people use monosodium glutamate, or MSG, as a flavor enhancer. However, MSG has been criticized by researchers for causing health problems. Instead, look for natural sources of umami like mushrooms and long-cooked sauces. Try adding a dollop of tomato paste or ketchup to a vegetable stew.