The latest round in our quest to find the best wine to pour with tri-tip, the rich and tender cut of beef that Californians love to grill in the summertime, was the most difficult. I'm not sure why. It could have been just too much of a good thing. The wines for this round were made with tempranillo, a black grape grown most extensively in Spain, where it provides the foundation for many of the highly regarded wines of the Rioja and Ribera del Duero appellations. We had just one Spanish tempranillo in our flight; the rest were from California, where the grape is just starting to be more widely cultivated.

Across the board, the wines were interesting and refreshing. They weren't blockbusters, their extraction, structure and weight running more to elegance than power. They were bright but not especially deep in color. While their flavors weren't heavily concentrated, they were seductively persevering, and their refreshingly crisp acidity made them splendid companions at the table.

They also were chameleons, shifting in tone more than any other kind of wine we've tasted in this series. I don't know why this was, but it prolonged our decision and prompted us to question what the pairing of food and wine is supposed to be about: As bites and sips are alternated are food and wine to blend into a kind of seamless unity wherein each loses its individual identity to become something more profound? Or are their individual identities not only to be retained but somehow enhanced by the matchup, each complementing without overshadowing the other?

Eventually, I'm sure, we would have come up with an answer, but first we had to get back to our original assignment. Besides, we were running out of beef. Ultimately, two of the candidates were our favorites. One was the Scribner Bend Vineyards 2004 Clarksburg Black Hat Tempranillo ($15), an earthy as well as richly fruity take on the varietal. It's a sturdy but juicy wine, with tannins that yielded gracefully to the richness of the beef. It also had intriguing floral and pie-spice notes. The other favorite was the Conde de Valdemar 2002 Rioja Crianza Tempranillo ($12), which combined a meaty texture, candied fruitiness and ripe, vivacious flavors into a wine that retained its identity while dovetailing neatly with the sweetness and spice of the meat. Both wines were found at the West Sacramento branch of Nugget Market.