The worldwide popularity of Rioja wines has made many people think of Spain as red wine country and little else. The truth is that Spanish vineyards produce more white wine grapes than red.

The acreage of vineyards on which white wine grapes are grown is also much more extensive than red and it’s a white wine grape, airén, that tops Spain’s production league.

Airén is cultivated on almost three times as much land as that used to grow the second most planted variety, the red garnacha. Airén, in fact, is the world’s most widely planted grape, red or white, in terms of acreage and most of it is grown in Spain, especially in La Mancha, Andalusia and Valdepeñas.

However, the best Spanish whites are not made with the airén grape. Spain’s most memorable whites come from grapes grown in relatively small quantities in the northwest of the country, especially Galicia and Rueda. One of these whites is Galicia’s albariño.

This grape is grown in the Rías Baixas area and many experts rate it Spain’s best white wine grape. I go even further and call it one of the world’s finest white wine grapes.

However, some 45 years ago albariño makers didn’t realise what a splendid grape they had in their vineyards. In those day the albariño vines were used mainly to mark the borders of orchards and other plots of land.

But by the time Rías Baixas won Denominación de Origen status (DO) in 1988, cultivators were well aware that the albariño grape was something very special and that the wines it produced were in a category all of their own.

The albariño grape is now one of the area’s main agricultural products and it makes an important contribution to the local economy. Even so, its cultivation is still very much a cottage industry. Of the four sub-zones that make up the Rías Baixas DO, only one has vineyards with an average size of one acre.

But in Rías Baixas it’s quality, not quantity, that counts. Small is beautiful there — and that even applies to the actual grape. The albariño is a tiny grape but it is packed with juice that is loaded with fruity and floral aromas and flavours. This is what helps to make albariño such a memorable wine.

In many ways, the albariño is a miracle grape. Nature endowed it with a thick skin that helps it to survive in Galicia’s particularly damp climate. It also takes advantage of the area’s relatively benign climate (temperatures seldom drop below 9C) to build up enough sugar content to produce wines with 13 per cent of alcohol, while maintaining a nice touch of acidity.

Albariño is one of the world’s mystery grapes: no one knows where it came from. It has similar characteristics to grapes grown in the Rhine and Moselle regions and some experts say German monks took those grapes to Galicia in the 9th century.

But other authorities claim that German monks, on a pilgrimage to Santiago de Compostela, took albariño grapes back with them and planted them in the Rhine and Moselle.

However, one of the greatest experts on Galician viticulture, José Luis Hernaéz Mañes, is convinced the albariño grape is simply a selection of clones that came from the grafting of native Galician grapes with vines brought in by the Romans.

Most of the world’s albariño crop is grown in Rías Baixas, with only a small amount being cultivated in Portugal’s Vinho Verde region, where it is known as alvarinho.

In Rías Baixas, albariño is grown on some 96 per cent of the vineyard acreage. The remaining four per cent is made up of caiño, loureira and treixadura, the other grapes allowed by the DO’s governing council.

In the old days albariños were always young wines bottled and distributed as soon as they were ready. Production was so low that for a long time the wine never left Galicia — in fact, there was barely enough for Galicians.

Even today, some 32 years after Rías Baixas was given DO status for it albariño wines, some 75 per cent is sold in Galicia, leaving only 25 per cent for the rest of Spain. The foreign market is a tiny one. Some Rías Baixas winemakers eventually fermented and aged albariños in oak casks. The oaked Fillaboa made by Isabel Salcedo was a huge success and won prizes at serious tastings and contests.

Bodegas Salnesur did an albariño fermented and aged in oak casks.

That’s about as complex as you can get with white wines. Other winemakers weren’t as daring and simply aged their albariños in stainless steel vats.

Those that have been fermented in oak (fermentada en barrica) and aged in wood (con crianza) and which you are likely to find in Palma, include Fillaboa, Valdamor and Pazo de Señorans. Some sell for more than €20.

Fillaboa also do a young albariño (which costs less) and which has been one of my favourites since I first tasted it more than 25 years ago at La Vinoteca in Calle Bartolomé Pou 28. Juan Luis of La Vinoteca has an excellent choice of albariños and he or one of his assistants will advise you on their merits.

With the exception of moscatel, albariño is the most potent of Spanish white wine grapes. It is in the same league as chardonnay, riesling, gewürztraminer and sauvignon blanc.

The most dominant fruity aroma is that of apples, but there are also floral nuances and sometimes a touch of honey.

When pairing albariños with food, they are superb with fish and shellfish — and they are best of all with raw shellfish such as oysters and clams.

If you are fortunate enough to have a plate of sea urchins before you, then an albariño fermented in wood and aged in the bottle for a couple of years will be the perfect partner.

This means you should consider drinking albariños with Japanese dishes such as sushi and sashimi. But when eating raw fish (with the exception of sea urchins with their rich iodine taste) I go for young albariños.

The more complex aromas and flavours of the oaked albariños overwhelm the delicate taste of most raw fish dishes. Fermented and aged albariños also match nicely with strong flavoured shellfish dishes made with lobster and crab.

And if you have ordered one of the more highly flavoured white fish dishes done with turbot, members of the bream family, sea bass or sole, then albariño (with or without oak) will be an ideal choice.

During the blazing summer months, do try drinking white wines at a much lower temperature than usual. Most whites should be served at about 10C, but in the summer my albariños and cavas are nearer 5C.

The colder a white wine is, the less we are aware of its merits and faults.

But in the unbearable heat of a Majorcan summer, I push the merits and faults into the background: it’s a glass of really cold wine I want.

There will be plenty of occasions in the autumn, winter and spring to consider a white wine’s intrinsic qualities.