Neurogastronomic Phenomenology for Advanced Beginners, Applied and Pure

(This one's a double-header on the tightly-linked senses of smell and taste, especially pertaining to foodcraft; it comprises both The Space of Olfaction is δ-Hyperbolic and A Partial Theory of Flavor Pairing in Foodcraft. You could read them in either order. I've chosen to put the more widely-appealing one about food phenomenology first and the less polished and more abstract and speculative one about olfaction second. Dedicated to SR-S and SS on the occasion of their marriage, and to the whole S family, who has already begun to benefit from this theoretical depth. Enjoy the sixspice buns!)(Part 1: Theory of Foodcraft. Epistemic status: only partially worked out, lots of handwaving, still not something I've seen talked much about explicitly anywhere.)(With thanks to @johnswentworth, @Morphism, @WhatsTrueKittycat, and MR and RG of Mox, among others, who all asked for this. If you asked me for this out of the list, it's also for you.)Food and drinks have flavors [citation needed]. In fact, they have lots of flavors - careful tasting of an ordinary bottled barbecue sauce presents sweetness and tartness and savoriness, and beneath those, tomato and molasses, and beneath those - if you get that far - mustard seed and paprika and onion powder and "some kind of fish sauce???". (It's Worcestershire sauce.) Some flavors blend nicely, like onion and garlic, while others clash, like onion and pineapple. But then some very different flavors pair just fine, like apples and cinnamon, or vanilla and nearly anything you'd find in a dessert. And even onion and pineapple go together just fine in the greater context of a salsa, or even a pizza! So what's going on?Here's a stab at explaining why. I'll use "food" as a term of art to mean anything intended to be eaten and enjoyed. A food flavor is comprised of two major parts: its tastes (sweet, salty, spicy, all the basic and chemosensory types) and its flavors (individual odorants, mostly associated with specific ingredients like cumi