Wine making, even in the 21st century, is a slow business in the Basque country.

The average vineyard holding is just a couple of acres and they are farmed part-time like a family allotment. It’s hard to speed up the process or do it more cheaply.

Tempranillo is the classic black wine grape of Spain and plays a starring role in rioja. Yields are a fraction of what they are for table grapes, such as Thompson seedless, which is the best-selling table grape and most planted variety in the world. Because the vines are mostly bush-trained almost everything, from pruning to picking, is done by hand. For this the growers receive just 60 – 70 eurocents (50 – 60p) per kilo, almost half what they were paid five years ago.

I was told this on a recent trip to Rioja, whose vineyards fan out on either side of the Ebro valley south of Bilbao, the Basque capital on Spain’s Atlantic coast. For now it seems there is enough pride in the wines for the mostly family businesses to continue, though you wonder if the next generation will be as happy to get down on hands and knees every other weekend.

But wine-making is deeply embedded here. I was shown a shallow stone trough beside the vineyards where medieval peasants would have trodden the grapes and fermented them. When ready, the wine would have been poured off through a sluice into leather gourds. Today the grapes all go to the local bodega or winery.

Here, too, the producers could grumble about the meagre returns of producing a decent bottle of rioja considering all the time and effort that goes into it. The house style is usually the Crianza which has to be aged for at least two years of which 12 months must be in oak. This minimum rises to three years for Reserva wines and five for Gran Reservas.

The slow transformation of wine in wood is a religion in Rioja and takes place in the vaulted cellars of every bodega where the stacked bottles and barrels inch their way to maturity. Nothing is released until it is ready for drinking which means tying up vast sums of money in stock – enough to make an accountant weep.

In the past some producers appeared almost reluctant to part with their top wines. Gran Reservas would be released so old that any fruit they contained had all but crumbled to dust. But today the emphasis is firmly on balancing the grapes’ fresh acidity and perfume with the oak’s mellow tannins and spice. By using younger casks, often a mix of new and one year-old wood, the better producers are tending to reduce barrel-ageing to retain the primary fruit flavours.

Most rioja is a blend of different plots of tempranillo, often spiced up with graciano, or given extra body with a dollop of garnacha. In white rioja you can now find chardonnay alongside the local viura, but international varieties like cabernet sauvignon are banned in the reds. This, say rioja producers, has helped preserve the integrity of Spain’s most famous wine.