Hygrothermal conditions for the biological aging of sherry wine

The present work analyzed the hygrothermal environment of several prestigious warehouses where sherry wines of “Fino” and “Manzanilla” type are made. Through descriptive statistics, frequency histograms and psychrometric diagrams of temperature and relative humidity variations have been obtained. In addition, other factors such as the stability and uniformity of the interior environment have been quantified. The results showed significant temperature variations throughout the year (limit values of 5 °C and 31 °C), with a more stable relative humidity (between 60% and 90% for most of the year). Indoor conditions varied much more rapidly than in wineries for the aging of red wine, as a result of constant ventilation. Therefore, the annual average stability was 2.0 ± 0.8 °C per day and 0.14 ± 0.12 °C per hour. Vertical uniformity decreased in spring and summer, with stratification values close to 0.5 °C/m and 3% r.h./m. The monitored indoor environment is outside the comfort ranges described in the literature for extended periods of time (in the most extreme case, 96% of the time outside the recommended interval). For that reason, a reference psychrometric comfort diagram was proposed. Industrial relevance For the first time, the hygrothermal behavior of several wineries producing high quality wines (very high scores in the oenological guides) was extensively analyzed. The results of the study, which include monthly comfort intervals, should be a very useful tool for the sherry wine industry, in order to control and ensure optimal development of the flor yeast film. It should also be taken into account for the correct design of new wineries or the rehabilitation of abandoned warehouses.