"H.J. van der Veen" wrote in
:

The main thing is: IF a Spanish wine is a Crianza, it MUST be labeled
on the bottle. The same with Reserva and Gran Reserva. There should be
a "back label" on the bottle, with the law-approved number, AND this
statement (crianza, reserva, gran reserva). If it isn't there, you can
almost be sure, that the wine is a young one (Joven).

Well, as you point, it is not always that way. It is true that each D.O.
(Denominación de Origen, similar to A.O.C.) has some rules for a wine to be
labelled as Crianza, Reserva or Gran Reserva. But it is also true that a
winery can sell a wine with a Crianza backlabel even if it could be legally
released as a Reserva. While this is not usually the case, there is a bunch
of wineries in Spain that are releasing their wines without aging
backlabel, that means... as a young wine, when they are not. And, some of
this wines are amongst the best.

Best,

Santiago