PART OF THE confusion is a matter of terms. The ancients grappled with how to categorize the sensations that come to us through food. As the classicist John Paulas outlines in his 2017 essay “Tastes of the Extraordinary: Flavor Lists in Imperial Rome,” the Greek philosopher Alexander of Aphrodisias, around the turn of the third century A.D., drew an Aristotelian axis with sweet at one end and bitter on the other, with six mixed flavors (oily, pungent, tannic, tart, sour, briny) making up the gradations in between, while the Roman naturalist and historian Pliny the Elder, in the first century A.D., proposed 10 standard flavors (with the notable additions of fresh and mild) and three paradoxes: the flavor that is perceived as singular when it is in fact a crowd of flavors conspiring at once, with wine as the exemplar; the flavor that does not fit any category and is sui generis to a particular food, like the “prevailing blandness” of milk; and the flavor that is the very absence of flavor, nullus, as in water. With this last philosophical gambit, “Pliny drops his audience into an abyss,” Paulas writes, “for the sake of sheer wonder.”
Modern science has dispelled some of these more rapturous ruminations and trimmed the list to five tastes, strictly corresponding to receptor cells on the tongue that react to chemical components in food. It’s these reactions, triggering the nervous system, that yield the traditional perceptions of sweet, sour, salty and bitter, as well as the relative newcomer umami, best understood as savory and meaty, a distinct taste identified by a Japanese chemist in 1908 and viewed somewhat skeptically by Westerners until the early 2000s, when scientists confirmed the existence of taste receptors that detect umami, in the form of the amino acid glutamate. These sensory perceptions were likely evolutionarily advantageous, according to Arielle Johnson, 34, a New York-based flavor scientist and the author of “Flavorama: The Unbridled Science of Flavor and How to Get It to Work for You,” forthcoming in 2023. We are able to recognize sweet, for example, because sugar is “the most basic form of energy our bodies can use,” she says, while salty indicates the presence of important minerals and bitter warns us of potential toxicity. There are an additional two “maybe” tastes, she says, with research ongoing into how we discern carbonation and fattiness (another building block of nutrition). Notably, spicy doesn’t count: From the perspective of neurology, we register the heat of chiles as touch, which is to say pain.
Flavor, however, is not taste. If taste is literal and thus limited, flavor is poetic and near infinite. It relies on scent as much as and sometimes more than taste, and scent not straightforwardly inhaled through the nose but carried retronasally, through passages at the back of the mouth. Historically, humans have always been judged at a deficit to animals in our sense of smell; a beagle, with its long snout, has 220 million to 300 million scent receptors against our measly six million to 20 million. But the Yale neuroscientist Gordon M. Shepherd has theorized that the extensive regions of our brain dedicated to olfactory processing give us an advantage, especially with a boost from the temporal and frontal lobes when memory is called upon to sift through smells and assign them meaning. Some scientists estimate that we can distinguish at least one trillion smells, far more than the colors we see or the tones we hear. And while we may not be as sensitive as animals when it comes to using smells to map territory, interpret hormonal signals or tell friend from foe, our experience of food is arguably deeper because of our advanced cognitive ability to parse the confluences of taste and scent. We think, therefore we eat — for pleasure, and not just survival.
THERE IS A weightlessness to floral flavors. They lack the voluptuousness of perfume or actual flowers, and arrive at the table filtered and secondhand, attenuated and almost austere. The pleasures of food are already ephemeral, plates soon emptied and spirited away, but these notes have a swifter evanescence, vanishing even as we try to pin them down. On a molecular level, pandan has kinship to jasmine and basmati rice, masa tortillas, crusty baguettes, Camembert cheese, pale lager, lobster tail and Iberian dry-cured ham: They all share the aromatic compound 2-acetyl-1-pyrroline, which lends a roasted, popcorn-like note. But science can only explain so much. If you drink water that has been steeped with pandan leaves, you don’t think of lobster or Camembert. The flavor is simply green — not grassy, not herbal, but green like a stand of bamboo after morning rain.