It's no surprise that there's a healthy bit of finesse into making a perfect cocktail - combining the spirits with balance, shaking or stirring with ice so the water dilutes it just enough, garnishing just so.
But, in the case of a drink with multiple ingredients and components, it turns out there's a bit of chemistry as well.
Neil Da Costa, an expert in chemical analysis of flavors at International Flavors & Fragrances Inc., reports, "Each of the main ingredients has been shown to contain many flavor components, thus indicating that a Bloody Mary cocktail flavor is a very complex blend of several hundreds of flavor compounds. These include semi- and non-volatile ingredients with chemesthetic effects such a heat, burn, sour, salty and umami."
So, what's actually going on?
Tabasco has "heat and burn sensations of capsaicin," tomato juice has lycopene anti-cancer health properties, black pepper offers "tingle effects from piperine," horseradish has "allyl isothiocyanate sinus-clearing effects" and Worcestershire sauce adds umami and an acid taste (umami refers to a pleasing savory taste and is often referred to as the fifth taste after salty, sweet, bitter and sour). Lemon juice adds an "unstable fresh lemon citral mix and sour citric acid," and vodka, of course, adds alcohol.
So, it seems it's best to use a mid-range vodka, high quality tomato juice, both Tabasco and black pepper, fresh lemon juice, Worchester for umami, and that the celery stick garnish is actually worth it.