What is NOT a qualification for a "reserva" wine in Portugal?

The concept of "reserva" in Portuguese wine regulations has specific criteria that define it. One significant aspect is that a "reserva" wine is required to be of higher quality than standard wines, often indicated by various factors like aging and production methods. The notion of blending is not a mandatory qualification; therefore, it is entirely feasible for a "reserva" wine to be a single varietal wine. This allows for the flexibility of winemakers to produce high-quality wines based on the specific characteristics of individual grape varieties, without the necessity to blend.

In contrast, the requirements regarding packaging in glass bottles, vintage status, and alcohol strength are all established criteria for a wine to be classified as "reserva." Packaging in glass is standard practice for quality wines, indicating a commitment to preserving the wine's integrity. The vintage categorization ensures that the wine reflects the characteristics of a specific harvest year, which is essential in conveying quality and origin. Lastly, the stipulation that the alcohol strength must exceed the legal minimum by at least 0.5% further emphasizes the quality aspect of "reserva" wines, ensuring that there's a distinction in potency relative to basic classifications. Thus, the blending requirement stands out as not obligatory for being designated as a