There are five things in a bottle of our Margarita Classic. Four of them you would guess: lime juice, water, organic agave, a little salt. The fifth is damiana, and it is the reason the other four are enough.

What it is

Turnera diffusa is a small woody shrub with little yellow flowers, native to a band running from southern Texas down through Mexico and Central America into South America and the Caribbean. The leaves are tiny — around 15mm long. Crush one and you get an aroma that sits somewhere near chamomile, warm and faintly spiced.

It belongs to the Passifloraceae family, which makes it a botanical cousin of passionfruit. We did not plan that. But it does mean our Pornstar Martini is passionfruit and damiana in the same bottle, two relatives that have never been introduced.

Why it belongs in a margarita

This is not our idea. In Baja California, and around Los Cabos in particular, damiana liqueur has been going into margaritas for decades — sometimes alongside the orange liqueur, sometimes instead of it. It contributes a honeyed, herbal note that gives the drink another layer to sit on, which is exactly what a margarita made of only lime and tequila tends to be missing.

There is a nice symmetry to it, because the margarita is a Baja drink to begin with. The stories compete: Danny Herrera at Rancho La Gloria between Tijuana and Rosarito in the 1940s, mixing something for a showgirl who could not drink anything but tequila. Or Carlos Orozco behind the bar at Hussong's Cantina in Ensenada in 1941, naming it for Margarita Henkel. Before either of them, the tequila daisy came out of Tijuana during Prohibition — and margarita is Spanish for daisy.

So a margarita with damiana in it is not a novelty. It is closer to the regional original than the version most bars pour.

What it does in ours

Aromatic sweetness, mostly. Damiana reads as sweet without being sugar, which is why we have never needed to add any — the organic agave handles the rest, and the damiana does the work that syrup usually does. Take it out and the drink goes flat and sharp, and the obvious fix would be sugar.

It also gives the Chilli somewhere to go. The heat arrives after the lime and leaves before the next sip, and the herbal note underneath is what stops it from being simply hot.

Where ours comes from

The damiana is sourced from its native range in Mexico. Everything else in the bottle is Australian, and the blending, batching and bottling all happen here in Byron Bay — the two of us, in batches small enough that we taste every one.

A note on what you may have read

Search damiana and you will find a great deal written about its traditional uses, most of it about effects rather than flavour. We are not going to repeat any of it. The plant turns up in nineteenth-century patent medicines and in a lot of modern copywriting, and the honest position is that its constituents have not been shown to do the things they are popularly credited with.

We use it because of how it tastes. That is the whole claim.