Can you produce a recipe with precise measurements? Can you tell me about the bar where it was popularized or the bartender who invented it, or when any of that happened, historically speaking?If you can’t answer any or all of those questions with rapidity or certainty, don’t worry - you’re not alone. And the reason why you’re not alone is because they’re not technically answerable questions. The Margarita cocktail represents a branch of the sour cocktail family tree that constantly forks and elaborates outward from its origins. But maybe “forking” is the wrong way to describe what the margarita does. The Negroni forks into a Boulevardier, which then forks into an Old Pal and a Man About Town. A Martini forks into a Vesper and a Gibson. But a Margarita radiates, spitting out little twigs and off-shoots specific to time, place, style and culture, all with different recipes, but all bearing the same name.I’ve always been fascinated with cocktails that seem to resist one or a few canonical recipes, cocktails so good and so easy that the point isn’t to worry about them or argue about them, but rather, to simply enjoy them. Here’s the catch with these kinds of cocktails, though: you can sip on a mediocre one and not give it a second thought, not be disappointed, but when you encounter a truly amazing one, it’s a thing of sheer beauty.In the end, my hope is to discover the true heart of the Margarita, to understand what makes it different from all the other sours in the cocktail pantheon. The internet is littered with recipes (good and bad), history (real and speculative), and plenty of brand-sponsored misinformation. And because of that - because I couldn’t find a resource that stripped down the Margarita to its essential components and then reassembled it for me to consider, I decided to tackle that project myself.I’m glad you’ll be with me on this journey because it begins many, many years ago, when the world was a very different place. So come along with me, and maybe pack a snack because to understand why the Margarita is such a delicious drink, we need to go back in time roughly 500 million years.The Worm and the MargaritaThe story of the Margarita, like any good story, begins with a worm. And we’re not talking about the worm in the mezcal bottle here, but a 1-millimeter-long roundworm known as C. elegans. In the days before mammals, before dinosaurs and reptiles, and before even the simplest fish swam in primordial seas, C. elegans split off from flatworms and other basic eukaryotes and started wiggling around in the mud. That is what worms do, after all. Things haven’t changed all that much in 500 million years…But C. elegans isn’t just any wiggly, little worm - it’s something known today as a “model organism,” which is different from when your third grade teacher called you a “model student” because I have a feeling your third grade teacher wasn’t studying your reproductive life cycle or actively mapping your genome. That’s what we do with model organisms: we look at how they reproduce, evolve, and respond to various stimuli in order to understand questions about the human body that are too complicated or unethical to test on humans.For more than 50 years now, scientists have been using C. elegans in various studies and experiments, and in 2002, it was the first multicellular organism to have its entire genome sequenced and mapped out for the world to see. One of the consequences of this work is that we can look at a gene that is present in the human genome, and then step into our genetic version of the “Way Back Machine” to see if that gene or gene family is also present in this very early, very rudimentary organism.OTOP1 - The Sour Perception GeneWell, it turns out that one gene family that you and I have in common with C. elegans is called OTOP1, which is responsible for our ability to perceive sour flavors. According to researchers, OTOP1 is “uniquely suited to mediate sour taste transduction” and “ not structurally related to any other known ion channel or transporter.”This is all a very complicated way of saying that, to the best of our knowledge, there were little worms crawling around in the mud about 500 million years ago, and their ability to perceive what amounted to sour tastes in their environment is directly tied to our ability to taste them in our cocktails today. Maybe not exactly what you want to hear as you take your first sip of a Margarita, but I think it points toward a very deep and very essential relationship between living organisms and sour tastes.From here, the question arises: why did organisms at any point in our evolutionary history need to know about the presence of something sour?Well, if you can extract yourself from thinking of sour as a “taste” for just a minute, it’s a little simpler to think of an acid as just a compound with some extra hydrogen ions. Let’s put on our chemistry hats here for just a moment - and I apologize in advance because I haven’t worn this hat sin