Red, white or rosé - the three categories we expect to see on every wine list. But now something called orange wine is appearing on menus at the world's finest restaurants, and being stocked at specialist wine shops across the globe. What is orange wine, and is the growing thirst for it, as some critics claim, just a passing fad?

Nothing to do with the citrus fruit, orange wine is white wine made as if it were a red. That is, it's made from white grapes, mashed up along with their skins and seeds. While white wine is produced with no, or very little, contact from grape skins, it's the red skins of red grapes that give the colour to red wine during the maceration process. The skins of white grapes impart an amber glow, hence the moniker orange wine.

Far from being a new fad, orange wine production goes back as far as 6,000BC, when it was made in the Caucasus, in modern-day Georgia. Wines were fermented in large subterranean clay vessels called qvevri, pronounced "kev-ree", which were closed with stones and sealed with beeswax. The reinvigoration of this ancient process has come about in the past 20 or so years. Orange wine is now being made, usually by small, independent and often experimental winemakers in countries as far afield as Georgia, Slovenia, Italy, the United States, Australia, France, South Africa and Austria.

Slovenian winemaker Aleks Klinec switched to producing only orange wines a decade ago. His orange wines, created on his small, yet venerable, six-hectare estate in the Goriška Brda region of western Slovenia bordering Italy, are some of the world's most respected.

"It's the traditional way of making wine in this region," Klinec says.

"I never liked modern wines. I've always preferred the taste of old-style wines. They are more authentic - you can feel the fruit, feel the grape in the wine. Modern wine all tastes the same; all this vanilla and tropical fruit - it's not real fruit, it's the casks and additives." Skin-contact maceration adds more than just colour. It also adds tannins - that dry taste we often associate with red wine. So in an orange wine, expect the intense astringency of a red, but balanced by freshness. As with all wine, orange wines differ wildly according to grape species, terroir and style of winemaking, but as a general guide, they are robust and bold with honeyed aromas of jackfruit, bruised apple, juniper and dried orange rind. They often reveal flavours of hazelnuts, brazil nuts and linseed oil, as well as sourdough.

The nuttiness and sour notes can be attributed to the wine-making process. Orange wine is not just a term that denotes another shade on the wine spectrum; it also generally, but not necessarily, suggests that the wine is "natural" - created with minimal technological intervention or use of chemicals.

Most orange wines are fermented only through the yeast that's already naturally present on the grapes. It's this wild yeast that imparts a sourness, reminiscent of fruit beer, to the wine. The nuttiness results from oxidation - many orange wines are made in open-top fermenters that allow for plenty of contact with oxygen. The wine is usually then sealed up after fermentation to mature. Most orange winemakers eschew the clarification process before bottling, meaning the wine can be cloudy.

"With orange wine, it's important to work naturally, in an organic way, to preserve the enzymes and yeast naturally occurring on grapes," Klinec says. "In a lot of wines made from commercial grapes, these grapes have been treated with pesticides and herbicides, which disrupts the winemaking process, and, of course, is damaging to the environment."

Klinec, whose estate is certified biodynamic, uses indigenous varieties of grapes, rebula (also known as ribolla gialla), malvasia, friulano, and verduzzo, as well as pinot grigio and merlot - both not local but introduced to the region in the time of Napoleon - to make his outstanding wines.

Orange winemaking is still in its infancy in most countries, making it difficult to pinpoint shared characteristics according to region. Craig Hawkins, a young winemaker making a name for himself for skin-contact white wine in South Africa's progressive winemaking region of Swartland in the Western Cape, says that as orange winemaking expands and develops, this will change.

"Like with any wine, you can pick up regionality, but because the 'database' is so small compared to normal white or red wines, this variance is a lot tighter. The more people we have making orange wines, the more regionality will start to differentiate itself," he says. "Techniques vary hugely and this is interesting to taste: a Georgian skin-macerated white is very different to one from South Africa, for example, as they have long skin-contact times, sometimes six months, and age in clay vessels, whereas ours are normally aged for weeks."

Hawkins, the talent behind the popular El Bandito labels, makes his wines mainly from chenin grapes. He describes his first taste of orange wine as "an epiphany moment".

"I was exploring the Old World wines of Italy and France, and while working in the south of France, sleeping in a tent and cooking meals on a gas stove, I had a bottle of orange wine with a meal. It challenged everything I had been taught about wine. I loved everything about it: the colour, the new flavours. In South Africa, we have these wonderful golden skins on our chenin, which we normally throw away after pressing, but this is where a lot of these flavours come from and I didn't want to lose them."

It's been eight years since Hawkins made his first wine, El Bandito Skin, and he says a lot has changed in the ensuing years.

"The market for orange wine is growing rapidly, purely because more people are making these wines and getting better at it with every attempt," he says. "There is more variation out there now for the consumer to relate to."

Today, specialist wine shops around the world often have an orange wine or two in stock, and wine bars and restaurants are featuring them on their menus. Orange wine is also making its way to Asia. Hawkins says his wines are especially popular in Japan, while Klinec exports to Japan and Hong Kong, and says that this year especially he's seeing noteworthy interest from the city. The main markets for orange wine are the United States, Britain and Australia, however.

Toasted, a wine shop, coffee bar and restaurant that specialises in organic and biodynamic wines in London, always has five or six varieties of orange wine from around the world on the menu. They usually sell only by the bottle, as the high cost of orange wine - usually because it is made in such small quantities - makes selling it by the glass prohibitive. As the wines have no chemical preservatives, they need to be drunk fairly quickly after opening.

"Orange and natural wines are just different," says Andy Broughton, assistant manager and "Wine Man" at Toasted. "When our patrons try orange wine for the first time, some will immediately like it, while others say, 'yuk! Give me a Burgundy instead'!"

Orange wine is no fad. It should rather be seen as a new wave away from the classic appellations. It's best to just forget what you already know about wine before you try it."

CHEERS TO ORANGE

An increasing number of wine bars and restaurants in Hong Kong offer orange wine. MyHouse, a Wan Chai restaurant that specialises in natural food and wine, stocks two orange wines, Lucy Margaux Gris Noir from Adelaide Hills, and Pheasant’s Tears Chinuri from Georgia, which is made in the traditional earthenware jars called qvevri.

Sommelier Alison Christ, founder of MyHouse, says about half of her patrons know about organic wines, and even less about biodynamic and orange wines. But she believes this will change.

“I see it becoming more popular with the help of dedicated sommeliers like myself. However, the supply is so limited that it will never become mainstream,” Christ says. “In Australia people know about it, but it’s still limited. In Japan they are quite savvy, and in Hong Kong it’s growing. I think China is out of the question as wine is viewed mostly as a status symbol and is always red, even if they prefer white or orange on the palate.”