Tomato juice

Tomatoes pressed and then sieved of skins and seeds. Thickness is what matters: a thin juice makes a thin drink, and body is most of what a Bloody Mary has. Petiot's own recipe asked for thick tomato juice, and rolling the drink instead of shaking it exists to keep that body intact.

Buy it not from concentrate, with the pulp left in, and unsalted if you can find it - the recipes here bring their own celery salt and Worcestershire, and a salted juice takes that decision away from you. European bottlings press Italian or Spanish tomatoes, which says more than any variety name does.

Pressing your own is brighter but thinner and sweeter, and it separates in the glass: raw tomato carries an enzyme that breaks down the pectin holding the juice together, which bottlers stop with a few seconds of heat. Worth doing because you want to, not as an upgrade.