What do reserva and gran reserva mean on a wine bottle?

Reserva stands for a legally defined minimum maturation, which is regulated per designation of origin in its own pliego de condiciones.

In Rioja, red reserva must mature for at least 36 months, of which at least 12 months in a 225-litre oak cask and 6 months in bottle. White and rosé reserva mature there for at least 24 months, of which 6 months in cask. The designation therefore says something about time and cask. It says nothing about the harvest or the plot.

Red gran reserva from Rioja matures for at least five years: 24 months in a 225-litre oak cask and then 24 months in bottle.

For white and rosé gran reserva from Rioja, a total maturation of 48 months applies, with at least 6 months in cask. The Consejo Regulador of the DOCa Rioja monitors these periods and issues the back labels bearing the designation. A gran reserva therefore only reaches the shop years after the harvest.

Ribera del Duero applies its own periods: red crianza 24 months, reserva 36 months and gran reserva 60 months, each with its own minimum in cask.

The pliego de condiciones of the DOP Ribera del Duero requires at least 12 months in oak cask for red crianza, likewise 12 months for reserva and 24 months for gran reserva. The wine spends the rest of the time in bottle. For white and rosé wine the periods are 18, 24 and 48 months. The pliego specifies casks of 330 litres.

In Italy riserva stands for a minimum maturation of two years for red wine and one year for white wine with a protected designation of origin.

Article 31 of Italian law 238 of 2016 sets those periods, including any affinamento. For sparkling wine with second fermentation in the bottle it is three years, for sparkling wine from the tank one year. The Italian riserva names no minimum in cask and no minimum in bottle, only the total time.

In Portugal reserva refers to an alcohol content that is at least 0.5% vol above the legal minimum, for a wine with distinguishing characteristics and a vintage year.

The Portuguese designation is laid down in Portaria 924/2004 and applies to wine with a geographical indication or designation of origin, bottled in glass. It comes with an assessment of organoleptic characteristics. Anyone who puts a Portuguese reserva next to a Spanish one is therefore comparing two rules that are about different things.