Caíño Blanco is an indigenous white Spanish and Portuguese wine varietal predominantly grown in northwest Spain and northern Portugal in a stretch of area between Vinho Verde and the Denominación de Origen (DO) of Rías Baixas. Caíño Blanco is a rare white varietal, and is often confused for Albariño (Alvarinho) and in Vinho Verde it is sometimes known under the name Alvarinhão - a synonym shared with another Portuguese grape, Fernão Pires.
Recent DNA profiling has concluded that the two grapes are distinct varietals. And the evidence has suggested that Caíño Blanco maybe a natural cross-breeding of Albariño and with the red Portuguese wine grape Azal Tinto (also known as Caíño Bravo) a rare grape varietal also indigenous to these remote wine regions.

 

Ampelographers believe that Caíño Blanco is native to the northwest Iberian Peninsula. It is believed that Caíño Blanco has been growing in the Spanish wine region of Galicia and the northern area of Portugal since at least 1722 when it was first recorded. So, therefore the crossing between Albariño and Azal Tinto would have had to occur sometime before the 18th century.
Swiss geneticist José Vouillamoz notes that the DNA evidence linking Caíño Blanco to Albariño and Azal Tinto is based on the analysis of only 27 genetic markers and that the Caiño family of grapes (which includes Caíño Tinto, Caiño Bravo/Azal Tinto, Caiño Berzal, Caíño Frexio and Caíño Redondo) have a very complex genetic make-up and history.
So this means it will require more DNA analysis to confirm Caíño Blanco's actual origins. The first clear and repeated records of this varietal were made in Cincinnato da Costa around 1890. Described as an aromatic varietal with small bunches and small round berries. Then again recorded in 1914 by Garcia de Salmones who described the varietal in and around the town of Pontevedra on the Iberian Peninsula as a popular varietal. There are ever so slightly more plantings of Caíño Blanco in Spain than Portugal but not by much.
Caíño Blanco is a mid to late ripening grape varietal which buds early to midway through the budding period for grape vines. The grape is susceptible to both downy and powdery mildew along with Botrytis as it likes to ripen late. It is almost exclusively used as a blending grape with Albariño in the region of Rias Baixas in northwest Spain. When added to the blend it helps to give the wines a boost in alcohol and refreshing acidity.
Caíño Blanco growing in Spain, virtually all can be found in the northwest Spanish wine region of Galicia where the grape is a permitted variety in the Rías Baixas and Monterrei DOs. In Rías Baixas, most of the plantings of Caíño Blanco are found in the O Rosal area where it is often blended with Albariño.
Though there are very few single varietal wines made from Caíño Blanco, it does help to give a citrus freshness to blended wines. Traditionally and still grown (with a few new vineyards planted recently) in the Galicia wine region of north-western Spain, with approximately 60ha of producing vineyards and some 10ha planted in Portugal.
Caíño Blanco tends to produce wines with high levels of alcohol with topical fruit flavours, good structure, lively acidity and mineral notes, though it does produce very little juice per berry. Caíño Blanco as a wine varietal is thought by those most familiar, that it has equal benefits when added to a wine as Albariño. Though it is agreed that the grape is far less well-known, it can add complexity and structure to a blend white wine.