(Decanter) - A difficult 2013 growing season has culminated in the Rioja DOCa council describing the vintage as 'good', the worst official rating for a decade.

Each of the Rioja DOCa vintages since 2004 inclusive have been rated as either 'very good' or 'excellent'. But, the appellation's ruling council has graded 2013 as just 'good' - a return to 2003 levels - after what it described as 'a difficult year for grapegrowers'.

There are two rungs, 'satisfactory' and 'average', that are worse on the council's scale. No vintage has dropped as low as 'satisfactory' since 1984, while one must go back to 1972 to find an 'average' rating, according to the council's vintage chart.

'The 2013 vintage growing cycle had weather patterns that were quite different to those of previous years,' said the DOCa council. 'Heavy spring rains and low temperatures delayed the growing season and resulted in uneven ripening.'

Good weather in September and October was largely credited with saving the vintage, allowing for a staggered harvest that enabled grapes to achieve ripeness. 'With such a demanding growing season, Rioja growers had to make full use of their expertise,' said the council.