There is a moment of hush as a man in blue overalls lifts the iron manhole cover, one of four set into the red-tiled floor. By the light of a single bulb set below the rim of the subterranean tank, we see the thick, golden liquid. He dips in a small metal bucket, pulls it up and empties it before dipping again and pouring out a steady, heady, perfumed stream.
This time Francisco Nunez de Prado, proud maker of all he surveys, thrusts a clean glass into the flow for tasting. He swills a sample around the glass and sniffs deeply - he smells freshly cut grass, he says, bitter oranges, and silvery-green olive leaves - before taking a sip.
The process is indelicate: He sloshes the oil about, allowing it to coat the surface of his tongue, his palate, before swallowing. "We are searching for a balance between fruit and spice," he says.
The result of the 1999 olive harvest has passed the test, as usual. This tank holds 13,000 gallons of flor de aceite, the "flower of the olive oil" produced by the Nunez de Prado farm, so utterly virginal it has not even been pressed.
The olives - grown organically on four estates around the town of Baena - are milled in the old style (granite rollers against granite floor) and then moved to a long cylinder of very fine steel mesh. As the cylinder rolls slowly, the flor de aceite drips down into a channel in the floor and then into the underground tanks. The remaining olive paste is then transferred onto round plastic mats and pressed gently to produce extra virgin olive oil with the strong, distinctive flavor indigenous to Baena: fruity, spicy, and bitter.
The Nunez de Prado oils are light years from the clear, pale olive oils sold to most Western consumers, who wrongly believe - Don Francisco, as he is known, shakes his head sadly - that olive oil should be seen but not tasted. His family eschews any filtration process, so the oil is cloudy with tiny, tasty olive particles.
Don Francisco sells a pint of flor de aceite for 700 pesetas (about $4.50), in a bottle that is sealed with red wax, stamped, and hung with a numbered label - all work done by hand. The economics of the business favor larger producers, since the European Union pays a subsidy for every kilo of oil produced. That subsidy can mean the difference between eating and starving for smaller producers.
Judging by the hearty lunch offered visitors - all courses, inc luding the dessert, cooked with olive oil - the Nunez de Prados make a good living. But, Don Francisco insists, "we are farmers, not businessmen."
Spanish cooks routinely fry potatoes in a liter (2.1 pints) of oil, which helps explain why Spain, with 40 million inhabitants, consumes some 400,000 tons a year, about half the national crop. Now it needs to persuade consumers in other markets to buy olive oil in similar quantities. Andaluca is one of the poorest regions of the EU and it relies heavily on the olive industry, which will be targeted again in the next round of agricultural reforms at a meeting this week in Berlin.
"That's why the subsidy is so important," Don Francisco says. "It depends on the price of oil each year, but for an ordinary farmer, the EU subsidy represents 30 to 40 percent of his income."