Lourdes Vega-Espinar

The reduction in alcohol content in Protected Designation of Origin (P.D.O.) ‘Jerez-Xérès-Sherry’ biologically aged wines represents a major regulatory and commercial milestone to align these historic products with modern global health trends. This study validates the feasibility of reducing the ethanol content from the traditional 15% v/v to 14% v/v through comprehensive industrial-scale monitoring under the traditional dynamic ‘Solera y Criaderas’ aging system the majority method in the region in two distinct wineries, followed by consumer preference testing and a 36-month bottle stability study. Industrial monitoring revealed that a 14% v/v ethanol environment promotes active flor yeast metabolic activity, as evidenced by sustained ethanol consumption and higher acetaldehyde accumulation, successfully maintaining active biological aging. Furthermore, volatile acidity remained consistently low, confirming the absence of significant microbiological alterations during the process. Hedonic consumer tests (N = 557) demonstrated that the 14% v/v wine is sensorially comparable to the 15% v/v control but significantly preferred, whereas a further reduction to 13% v/v reduced sensory balance and overall consumer acceptance. Over 36 months of bottle storage at 20 °C, the 14% v/v wine maintained high physical stability, preserving its characteristic pale gold color, clarity, and essential biological aging profile (including ’yeast’ and ‘nuts’ descriptors). Minor differences in browning (absorbance at 420 nm) emerged at 24 and 36 months (p = 0.0066) but did not impact overall quality. Crucially, the official tasting panel of the OECCA Foundation formally declared all 14% v/v samples as compliant with P.D.O. organoleptic specifications throughout the entire 3-year study. These findings demonstrate that reducing the alcoholic strength of Fino-style wines to 14% v/v is technically and commercially viable under traditional dynamic aging conditions, preserving enological heritage while satisfying modern consumer demands.

Lower-alcohol static biological aging boosts flor metabolism and preserves sherry typicity. This approach enhances industry sustainability by reducing fortification costs and CO ₂ emissions.

Spanish “Fino”-style white wines are traditionally aged by a dynamic process under a flor veil of Saccharomyces cerevisiae, requiring ≥15% (v/v) ethanol, which is typically achieved through fortification. Market demand for lower-alcohol wines and the need to reduce production costs have encouraged the development of alternative approaches. Here, static biological aging was evaluated as a method for producing Fino-type wines with reduced ethanol content. Base wines with ~14% and ~15% (v/v) ethanol were aged for nine months, during which chemical, microbiological, and sensory parameters were analyzed, along with flor veil activity. Lower-ethanol wines showed greater flor activity, with approximately 20 more yeast isolates in the wines with 14% (v/v) ethanol. Higher acetaldehyde levels were detected in these wines, reaching about 377 mg L⁻¹ compared to 230 mg L⁻¹ in the control wines (≥15% v/v ethanol). Significant changes were observed in pH (3.13–3.47 vs. 3.04–3.46), volatile acidity (0.20–0.26 g L⁻¹ vs. 0.31–0.66 g L⁻¹), and several volatile compounds, resulting in chemical and sensory profiles consistent with traditional biologically aged wine. Static biological aging can yield lower-alcohol Fino-style white wines with sensory and chemical attributes comparable to the traditional fortified versions, providing a cost-effective alternative that aligns with evolving consumer preferences.