Richard Geoffroy projects the gentle gravitas of a physician, which is only natural because he is a physician by training.

But his medical degree from the University of Rheims has little to do with his day job – chef de cave of the fabled French Champagne, Dom Perignon.

“In fact, I never worked as a doctor,” Mr. Geoffroy said the other day during a brief visit to New York. “I come from a family of seven generations of grape growers, but I went to medical school because I felt like doing something more idealistic.

“After my medical degree, however, I found the attraction of my roots much too strong, so I decided to get another degree, this time in winemaking,” he said. “After that, there was no question that I would go into the Champagne business.”

It is a fiercely competitive business, not the least because by tradition grapes used to make Champagne can be grown only in a 32,000-hectare area in the Champagne region of northern France, some 80 miles northeast of Paris near the Belgian border. The name “Champagne” is legally protected under the 1891 Treaty of Madrid, which means that only sparkling wines produced in Champagne can be legitimately called Champagne.

Mr. Geoffroy is marking the completion of his first decade as chef de cave, or cellar master, a job that’s arguably the most prestigious – and the most powerful – in the $30 billion-a-year Champagne business.

That business is growing again globally after a brief slump following the millennium celebrations in 2000, according to the Champagne trade body Comite Interprofessionnel du vin de Champagne. The CIVC says worldwide shipments in 2005 were up 2%, to 307.5 million bottles, the second year in a row that sales edged beyond the 300 million mark. Britain is the world’s largest importer of Champagne, followed by Germany and America.

Mr. Geoffroy has a special affection for America.

Before he joined Dom Perignon, he traveled to Napa Valley in California and spent a year there.

“California was where it all really started for me,” he said. “I learned the basics of winemaking there. Perhaps that’s why I’m strongly drawn to America. I’m one of the very few top winemakers in France to have studied winemaking in America.”

To qualify as a top winemaker in France, Mr. Geoffroy spent several years developing vineyards in far-flung places such as Australia. In 1990, he was appointed as an understudy to one of the great figures in French winemaking, the man who was then chef de cave of Dom Perignon, Dominique Foulon.

“At first he would be silent, just letting me watch him at work,” Mr. Geoffroy said of Mr. Foulon. “But then he began to warm up to me, and became a wonderful teacher.”

Mr. Geoffroy succeeded Mr. Foulon as chef de cave in 1996, which also happened to be a great vintage.

Mr. Foulon taught Mr. Geoffroy that a chef de cave runs a complicated operation. He is the one who determines when an assemblage – a blend of white wines known as the base wines – is ready to be transformed into the heady sparkling wine. That transformation occurs through a secondary fermentation in bottles, which creates the bubbles.

The brew is then allowed to age for at least seven years. Then sediments are removed through a process known as riddling and disgorging. After recorking, the bottles are then stored for another six months before being dispatched for sale.

The process can be traced back to the 17th century, when a monk at the abbey of Hautvillers, Dom Pierre Perignon, perfected a technique for creating sparkling wine.

“Our wine is a tribute to the creator of Champagne, a man who was all about inspiration, vision, and charisma,” Mr. Geoffroy said.

Mr. Geoffroy also determines for Dom Perignon which year’s wines should be designated as vintage. Vintage Champagne is made from wines produced in a single year exclusively, while a majority of Champagnes are non-vintage and consist of a blend of wines from different years. Dom Perignon is vintage Champagne exclusively, and made no more than six times every decade.

“I have a memory of every single vintage going back many decades,” Mr. Geoffroy said.

“To carry the name of the Dom Perignon brand, there’s an element of responsibility to it, not to mention pressure,” Mr. Geoffroy said. “Making Dom Perignon isn’t just about mastering winemaking techniques. There is a strong element of creativity; it’s about subjectivity and taking risks. Every single vintage is unique.

“Instinct is important in creating the unique style of Dom Perignon – an ethereal sensation on the palate, and a caressing texture of the Champagne.”

He paused, contemplating a glass of chilled water, and then said: “The philosophy is about representation of an ideal, the absolute ideal of what great Champagne should be. This is an endless quest. It’s about sophistication, and it implies complexity, harmony, and integration. It’s about appealing to the senses. The enjoyment of Champagne, of course, is a very personal experience. And so what I create must take into account all these elements.”

Mr. Geoffroy sometimes draws Champagnes from what he calls the “oenotheque” of Dom Perignon. The reference is to a wine library that holds all vintages going back to 1921.

“That’s our legacy, our patrimony, and memory. It holds the DNA of Dom Perignon,” Mr. Geoffroy said. “What it means is that I am able to re-release the older wines as ‘Dom Perignon Oenotheque’ for contemporary consumption.”

Dom Perignon is more in demand than ever. It sells for between $130 and $10,000, depending as much on the vintage as on the size of the bottle. Mr. Geoffroy last week released the Dom Perignon Mathusalem in New York, the equivalent of eight bottles.

“Champagne is part of the world culture, and the world culture is rapidly embracing a sophisticated lifestyle, where wine and food play an increasingly significant role,” Mr. Geoffroy said. “It’s about fulfillment and enjoyment, and about discovery through new adventures and sharing those experiences. Drinking Dom Perignon is bliss.”