(Reuters) -- Rivella is Switzerland's second-best selling soft drink after Coca-Cola. Now the Swiss company hopes to tap the huge potential of non-Rivella drinkers at home and abroad with a new product, Rivella Green.

(Reuters) -- Rivella is Switzerland's second-best selling soft drink after Coca-Cola. Now the Swiss company hopes to tap the huge potential of non-Rivella drinkers at home and abroad with a new product, Rivella Green, which contains green tea extracts.

"Rivella is a divider, you either like it or you don't," said chief executive Franz Rieder, adding that he believed Green could boost total output by 10 percent and sales by more.

In Switzerland, Coca-Cola Inc has a market share of more than 50 percent, Rivella has 12.5 to 15 percent and PepsiCo Inc less than 4.5 percent, Rieder said.

Rivella's specific taste limits its export potential but the group is convinced it can sell more and further away than now.

"We have not really been selling in Italy or Spain because southern Europeans prefer sweeter drinks," said Barth, adding that in the United States taste was influenced by cola. "They want it strongly carbonated and with ice."

But in Switzerland, Luxembourg and the Netherlands it is well established. "If you calculate it per head of population, we have our biggest market share in Luxembourg," Barth said.

Rivella, its name derived from the Italian word for revelation, sells in southern Germany and the east of France. The company recently started exports to Britain and the United States, where it is a niche product.

In the Netherlands, which takes 90 percent of total Rivella exports, the group used to be associated with Dutch dairy group Friesche Vlag. But sales dried up and the brand became associated with grannies wanting to stay young.

"It's a bit strange but it tastes good," is the slogan now used in the Netherlands. In Switzerland, the group advertises its new product line-up with the slogan "What colour is your thirst?".

The history of Rivella goes back to 1950 when Robert Barth developed a way to make a soft drink from milk serum or whey -- the liquid that remains when the protein and fat is taken out of milk. It used to be a by-product of cheese making.

Barth did not invent the method, but the recipe.

"My uncle had studied law, just like my father, and he wanted to go the United States to represent companies and products. After putting up an add to ask for products, he received a letter from a German who had found a way to make a soft drink from milk serum," Barth said.

"My uncle did not want to take it to the U.S. but my father became interested and bought the patent from the German," he added.

The Barths tested recipes in the kitchen, adding herbs and other ingredients, until they struck on formula for a drink that is still known as Rivella Red. It contains 30 percent whey, is slightly carbonated and has a sweet-sour taste somewhere between apple juice and yoghurt with a hint of ginger ale.

Robert Barth's company made losses for at least 10 years. It survived because of the wealth of his father who was a banker.

The company started in Staefa near Zurich in 1952 and moved to Rothrist in the northwest in 1954. In 1959, Barth added Rivella Blue to the line-up -- a low-calorie version.

Rivella also branched out to fruit drinks, launching Passaia with passion fruit and buying the Grappillon grape juices in 1971 and Michel fruit juices in 1983.

The latest product developments were in 1997 when Rivella launched both Michel Ice Lemon and Michel Bodyguard -- a multi-vitamin drink. This year, 40 years after Rivella Blue joined Rivella Red, the company added Rivella Green.

Robert Barth and Rivella became closely associated with Swiss sports organisations and the Olympics. Rivella still provides both amateur and professional sporting meetings with logistical help.

Rivella is the official drink of many Swiss sports teams including the Olympic team. "We're always the smallest sponsor, compared to the banks or Swissair," said Rieder.

This included the 1996 Atlanta Olympic Games where Coca-Cola was the official drink. "Coca-Cola did not like it at all but we were there. There was a Swiss pavilion and Swissair helped us to present Rivella in the lion's den," he added.

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