In the early 1970s, finding a good Californian wine in Paris was surprisingly difficult. Patricia Gastaud-Gallagher knew this particularly well. As an American working at L'Académie du Vin, she had encouraged the school to organise annual Fourth of July tastings, but the American bottles available in France rarely made a convincing impression.

Meanwhile, reports of promising wines from Napa Valley were reaching Paris. Patricia had reason to believe there was something worth discovering, even if the wines themselves were almost impossible to find.

With the United States approaching its bicentennial in 1976, an American wine tasting in Paris seemed a particularly fitting idea. Patricia later recalled that she had already been considering such an event before travelling to California in 1975. Spurrier's recollection placed the development of the plan somewhat differently, after her return.

What is clear is that Patricia's interest in Californian wine helped set the project in motion. During her visit to the region, she sought out producers whose wines were largely unknown to the French professionals she hoped to introduce them to.

Following recommendations from wine writer Robert Finigan, Patricia visited a number of wineries. Almost everything she tasted impressed her, but two producers stood out: Château Montelena and Stag's Leap Wine Cellars.

Neither was a name that carried much weight in Paris. Yet what Patricia found in their cellars seemed considerably more interesting than the American wines she had been able to obtain in France.

She returned without samples, but with detailed impressions and enough enthusiasm to persuade her colleague Steven Spurrier to investigate further.

Their professional relationship had begun in 1971, when Patricia, then writing for the International Herald Tribune, answered an advertisement for Beaujolais Nouveau. The young English merchant she encountered unloading cases from his car was Spurrier, who had driven through the night from Beaujolais to Paris to deliver the new vintage.

They became friends, and Patricia joined his wine business and school. Both believed that wine education should involve tasting and discovery rather than unquestioning acceptance of established classifications.

Spurrier was particularly well placed to develop the California project. His knowledge of French wine and relationships within the Parisian wine world gave him access to professionals who might otherwise have paid little attention to unfamiliar American producers. He was also curious enough to make the journey himself.

In April 1976, Steven and his wife, Bella, travelled to Napa Valley, where Joanne Dickenson DePuy, who ran Wine Tours International, helped them navigate the region's wineries. Joanne introduced them to producers, including Château Montelena and Stag's Leap Wine Cellars, and later played an essential role in arranging transport of the selected bottles to France.

By the time the wines arrived in Paris, a modest bicentennial celebration had developed into something rather more ambitious.

THE REPUTATION IN THE GLASS

Steven Spurrier decided to serve the Californian wines alongside established French examples, with the identities of the bottles concealed.

It was an intriguing decision, particularly given the people he had invited.

The nine French wine professionals who attended the tasting on 24 May 1976 included some of the country's most respected names. Among them were Aubert de Villaine of Domaine de la Romanée-Conti and Odette Kahn, editor of La Revue du Vin de France. These were people whose professional judgments were grounded in considerable experience.

The French wines selected for comparison had equally formidable credentials. Great Burgundy and Bordeaux estates had spent generations establishing reputations that extended far beyond their regions. Their prestige was neither accidental nor undeserved.

And yet, I keep wondering what would have happened if the labels had remained visible.

Imagine tasting a Chardonnay knowing that one glass contains a celebrated white Burgundy, while another comes from a Californian winery whose name means almost nothing to you. Even before considering the aromas or texture, you already know which producer has generations of prestige behind it.

Would that knowledge influence your judgment?

Perhaps not. Experienced tasters are trained to recognise quality independently of a label. But familiarity can shape expectations even when we are convinced that we are being objective.

What interests me is that Spurrier did not ask the French professionals to set aside their expertise. Quite the opposite: he invited them precisely because their judgments mattered. Removing the labels simply meant that the wines would have to make their case without the assistance of their reputations.

THE AFTERNOON IN PARIS

On 24 May 1976, the tasting took place at the InterContinental Hotel in Paris.

The white-wine flight brought Californian Chardonnays together with celebrated Burgundies. The red-wine flight placed Californian Cabernet Sauvignons alongside distinguished Bordeaux wines.

The tasters evaluated the wines blind, unaware of which bottles came from France and which from California.

When the scores were collected, the highest-ranked white wine was Château Montelena's 1973 Chardonnay. The highest aggregate score among the reds went to Stag's Leap Wine Cellars' 1973 Cabernet Sauvignon.

Both were Californian.

The results were remarkable, although they did not establish that California was universally superior to France. A single afternoon could hardly settle such a question, nor did it erase the achievements of the French estates represented.

But two relatively unfamiliar American wines had received the highest scores in a tasting conducted by respected French professionals, alongside wines with some of the most prestigious names in the world.

George Taber, a journalist from Time who attended the event, recognised the story's potential. His reporting helped transform what Patricia and Steven had conceived as an educational tasting into the event that became known as the Judgment of Paris.

The American victory made an irresistible headline. For Patricia, however, the transformation was uncomfortable. She had wanted to introduce interesting wines to French colleagues she respected, not expose them to public embarrassment. Years later, she recalled her distress at seeing a friendly tasting portrayed as a contest in which the French participants had been defeated.

The irony is that the wines themselves had never been intended as weapons in a national rivalry. California's winemakers had been developing their craft for years, experimenting with vineyards and techniques, often with considerable respect for European traditions.

The tasting did not suddenly make those wines good. It made their quality harder to overlook.

WHAT ELSE HAVEN'T WE TASTED?

The Judgment of Paris became a defining moment in the international recognition of Californian wine. Its consequences extended well beyond the two winning producers, encouraging a wider audience to take wines from outside Europe's traditional centres of prestige more seriously.

Yet the part of the story I find most compelling happened before the results were announced.

Patricia had heard that interesting wines were being made in California, but the bottles available to her in Paris offered little evidence of it. She could have accepted that limited selection as representative of American wine. Instead, she went looking for what was missing.

Steven, despite his established position in the French wine world, was willing to follow that curiosity, taste for himself and organise an experiment whose outcome neither of them could confidently predict.

Their professional experience made the event possible. Their willingness to explore beyond it made the event worth organising.

There is something particularly appealing about that combination. The more we learn about wine, the more names, regions and vintages we come to recognise. Some deserve their reputations completely. But the pleasure of discovery depends on remembering that the wines we already know are not the only ones worth knowing.

Wine is never just wine. Sometimes discovering something new begins with being curious enough to question what you already know.