The Welshman of the I Greppi quartet is Dale Heatley, the General Manager, who moved to Italy to play rugby and never left. "It's a bit like Moneyball," he says, referring to the Brad Pitt movie in which a baseball team is revitalised by a disparate group of players chosen by algorithm.

 Dale's approach to strengthening the team, however, has not been quite so mathematically precise: he brought Marco Filippeschi, the marketing manager, on board after meeting him at an enology event in the Italian capital, Rome, and he met much-valued Albanian cellar hand Ervin through rugby: "He's got a good engine on him: he's our muscle man, and he scrubs the winery to within an inch of its life."

Hygiene is a subject close to the Californian winemaker's heart. Keaton Crow is a graduate of University of California, Davis, in viticulture and oenology, and he was I Greppi's first intern in its annual program with UC Davis. "To me, it's about being so clean that you can be dirty in the right ways.

"All great wines use porous materials - wood,  for example - which is inherently impossible to sterilise, but it gives true character to the wine." Remove all the unwanted variables, he thinks, and you have a much clearer picture of what you do want. "It's all about understanding how and why the wine evolves, and that's where the science comes in."

 Connoisseurs of Greppicaia and Greppicante need not worry unduly about levels of lactic acid before and during malolactic fermentation; or about the effects of heat and oxygen in stabilising colour and producing an expressive mid-palate; still less about biogenic amines and their potential impact on purity and flavour: Keaton has worried about all those things already, on their behalf.

In conjunction with his alma mater, he has an eye on the future, too. "When I'm in the lab at I Greppi, I'm just thinking about our wines, but the projects on which we're collaborating with UC Davis - and we now have contributing winery partners in Napa as well - have much greater scope. It's a multi-year endeavour with them, with tremendous learning potential, but it's a long game and really requires patience.

Science is about informing decision. The best juice is always created in the vineyard, and perhaps the most important single decision we have to make every year is when to pick the grapes.

 "Of course, factors like weather forecasts and the availability of labour enter the equation, as well as sugar ripeness, but this year we are the first winery in Italy to partner with a US company that analyses tannin and colour."

And what of the 2021 vintage? Dale, speaking in mid-August, is optimistic: "We could do with a drop more rain, but that usually happens around the end of August and beginning of September. We lost quite a bit of Merlot earlier in the year, because of frosts, but it's always very abundant so that's not really a problem."

The frost in mid April meant I Greppi lost some Merlot. The summer has been hot and sunny with above average temperatures while precipitation has remained low. This echoes the conditions of some of the great vintages in the Bolgheri area such as 2016. While volumes will be down, the quality will be high. We are expecting 2021 to be a harvest that will be spoken about for years to come.

There are challenges ahead for all winemakers, especially global warming. Bolgheri benefits from the cooling influence of the Mediterranean, which keeps temperatures down in summer and helps to prevent frosts, and I Greppi also benefits from the two lakes in the middle of its vineyards, which mitigate the fierce summer heat.

Merlot, though, is especially susceptible to high alcohol levels in very ripe years: recently, I Greppi have ripped up four hectares of old Merlot vines and replanted with a different Merlot clone, one that is more heat resistant; increasing the percentage of Petit Verdot, a splash of which goes into both of the flagship wines, is another possibility for the future.

For the moment, though, Keaton is content to record in intricate detail the data and decisions that inform each year's wines: every vintage, in effect, has its own exhaustive biography. "Our philosophy is to do more work, so we can do less and add less. And, maybe in a decade or so, I want to open a bottle of fully mature Greppicaia, pour myself a glass, and say 'Wow! This is fantastic! What did we do ten years ago?' And we'll be able to answer that question."