All olives are born green and turn black as they ripen. In Nice we like our olives tournantes: on the edge of ripeness, between the two. That’s how Nicolas Alziari takes them to make its famous olive oil. “The company dates from 1868,” explains deputy director Vincent Piot. "But there’s been a mill here for about 300 years,” Vincent says this lightly, as if three centuries were a small thing. He’s the latest in a line — his father before him, his cousin’s grandfather before that. The name Nicolas Alziari has been on bottles since the Second Empire.

The mill sits in a cool valley in the hills behind Nice, and is open to the public; anyone can bring their olives here to be turned into oil, even a kilo will do. There are fewer and fewer traditional mills offering this service, but Vincent keeps the mill wheels turning for anyone who needs. Even when it’s quiet, even when the tourists are gone. Because if the wheel stops, so does the craft. “I say, ‘No, no, we’re staying open no matter what. It’s our choice to open, because that’s what makes us happy,’” he says.

Nicolas Alziari still uses the méthode génoise to make its oil, one of the last two houses in France to do so. Instead of pressing the paste straight away, they let it rest in water until the oil rises naturally to the surface – a precious harvest known as the fleur d’huile d’olive. It’s a yield so small it barely makes commercial sense, but that isn’t the point. Tradition here is not a marketing word. It’s the rhythm of a craft that refuses to die quietly. After this, the first pressing takes place, and then the oil is filtered before bottling.

Vincent explains the harvest like a winemaker describing grapes. He talks of the grands crus and of the assemblage of the house blend, mixing oils of different varieies to create the consistent flavour that customers keep coming back for.

Every drop counts. Nothing is wasted. If the olives are not made into oil, they’re salted and cured and become tapenade or table olives, even soap. From careful hand selection to bottling in formats ranging from 100-millitre “mignonnettes” that can be carried in hand luggage on an aeroplane to elegant one-litre bottles, destined for the delis of London, New York and Tokyo, the Piot family ensures their craft travels the world without compromise.

Nicolas Alziari recently bought olive groves in Provence and soon it will be 100% self-sufficient and organic. And that’s how it will advance – one foot planted firmly in tradition, one striding towards the future.