A General Theory of Deliciousness

Reader Penelope wants to know if I have any ideas about why herbs, spices, and flavorings — like vanilla — exist at all. Do they serve a purpose in nature? And if so, what is it?

Penelope they certainly do serve a purpose in nature: they are delicious. My personal belief is that God put them there so that we average schlubs might enjoy a decent pot de crème every so often, however I recognize that my theory lacks scientific rigor.

As it happens there is another theory, one which also lacks a certain amount of scientific rigor: the scientific explanation. The central idea here is that chemical compounds contained in a plant which are not essential to the plant’s survival (i.e. which aren’t related to the plant’s growth, metabolism or reproduction) are defensive in nature. Which is to say they are designed to protect the plant from predation by microbes, insects and larger animals, and also protect them from, say, too much exposure to the sun.

These so-called “secondary metabolites” make up an incredibly diverse family of chemicals ranging from phenols (pigments as well as the flavonols and flavonoids that give pods and seeds like vanilla, nutmeg, coffee and chocolate their flavor) to terpenes (the essential oils found in leafy herbs like basil, mint and citrus) to alkaloids and glycosides (everything from the bitter tasting compounds in kale to nicotine, cocaine, heroin and cyanide). There are many others besides.

The idea that pigments protect from the sun and cyanide helps keep large herbivores from eating too much escarole, well, I’d say there’s pretty compelling evidence to suggest those theories are true. Far less is known about what specific pests vanillin or eugenol might protect against. Probably there is some sort of evolutionary answer out there. Until that’s definitively found, though, I prefer that notion that universe wants me, personally, to enjoy my ice cream.

20 thoughts on “A General Theory of Deliciousness”

  1. Its possible you are headed in the right direction. Perhaps the vanilla bean smells and tastes the way it does to entice specific animals to eat them & deposit the seeds in a small pile of natural fertilizer.

    Or perhaps the flavor and aroma are just an accident but humans found them pleasing and so they encouraged the spread and ensured the success of the plant.

    I’m OK with any of those explanations 😉

    1. Another possibility is attracting insects/birds/animals to pollinate the plant. I know there are pigments only visible by infrared (not sure about ultraviolet) that make some flowers attractive to pollinators, with the route to the pollen nicely marked out in “color”!

      1. UV as well – I remember seeing pictures of various flowers under a blacklight many years ago on one of the PBS nature shows, pointing out the line to the nectar (and pollen!) in the flower. I think those were attractive to some sort of insect that can see into the UV range.

        A number of the plants commonly used as herbs and spices have antimicrobial properties – possibly the interesting flavour compounds provide the plant with protection against attacking microbes.

        I also wouldn’t discount the effects of a few thousand years of human tinkering, either: I wouldn’t speak to what the ancestral basil plant in the Mediterranean 5000 years ago tasted like, other then probably not much like the modern stuff. Any plant that’s been under domestication any length of time has been selected and hybridised extensively to human tastes. (Which poses an interesting problem for those of us interested in historical food and cooking, but that’s another essay altogether.)

          1. I have wondered whether the natural anti-microbal action of some herbs/spices may have been borrowed by earlier humans for the purpose of (short term) food preservation, and whether our tastes have been modified on an evolutionary level to prefer the flavor of those herbs/spices that performed this very useful function.

            Do we enjoy these useful flavors because they are naturally delicious? Or are these flavors delicious to us because they have been so practically useful?

            Life is a puzzle.

          2. Well done OOTT…in days gone by many herbs were indeed used as preservatives…which is evidence of anti-microbial powers that I didn’t consider when I wrote this post. Excellent! Thanks for a very thought-provoking comment!


            – Joe

  2. I wish my tomatoes had more “secondary metabolites” so that the birds and beasties would stop pecking a single bead- or pea-sized hole in every one as it begins to ripen. Damn! They could pig out on an entire one or two and leave me a single pretty one but they’ve gotta sample Every. Last. One… grrrrrrrrrrr

    1. Those are the worst! Squirrels do that here in Kentucky. Drives me flippin’ crazy!

      – Joe

  3. Aphids are my worst garden pest right now, but they despise basil, sage, rosemary and tomatoes. Here in Wyoming, it’s the two-legged predators that get to the tomatoes. They steal them just when they’re about perfect while you’re at work. Let’s not talk about what the deer do to anything that isn’t an herb or tomato.

      1. It’s a place where men are men, women are men and squirrels are…

        I chalk it up to all of the natural gas drilling in the surrounding counties – and all of the Good Stuff coming up here from Colorado. We only get 5 or 6 flights from Denver a day.

  4. Your first answer totally works for me. Scientist, I am not. Lover-of-delicious-carbs-alongside-a-cup-of-tea, I most definitely am.

  5. Don’t forget, most of these plants have experienced two to ten thousand years of selective pressure to be more productive and tasty- often at the cost of natural resistances….

    1. Hey Eric!

      Jane just made a similar point down below, and it’s an excellent one. Full credit all around!

      Many thanks,

      – Joe

  6. Plants were also the only medicine available to humans for a very long time and their aromas were helping to distinguish between what’s good and what is poisonous.

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